diff --git a/.flake8 b/.flake8
index bf8d2ed..0448813 100644
--- a/.flake8
+++ b/.flake8
@@ -4,6 +4,8 @@ per-file-ignores =
     __init__.py: F401
 max-line-length = 120
 ignore =
+    # line break before binary operator
+    W503
     # whitespace before ':'
     E203
     # Missing Docstrings
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 41a282e..3cc5b97 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -12,8 +12,7 @@ on:
       - main
 
 jobs:
-  build:
-
+  lint-test-coverage:
     runs-on: ubuntu-latest
     strategy:
       matrix:
@@ -21,10 +20,12 @@ jobs:
 
     steps:
     - uses: actions/checkout@v2
+
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v2
       with:
         python-version: ${{ matrix.python-version }}
+
     - name: Cache pip
       uses: actions/cache@v2
       with:
@@ -48,7 +49,53 @@ jobs:
         flake8 . --count --exit-zero --max-complexity=10 --max-line-length=100 --statistics
     - name: Run linting environment and pre-commit hooks
       run: |
-        tox -e linting
-    - name: Test with pytest and coverage via Tox
-      run: |
-       tox
+        tox -e lint
+
+
+  tox-coveralls:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Python 3.7
+        uses: actions/setup-python@v2
+        with:
+          python-version: 3.7
+
+      - name: Set up Python 3.8
+        uses: actions/setup-python@v2
+        with:
+          python-version: 3.8
+
+      - name: Set up Python 3.9
+        uses: actions/setup-python@v2
+        with:
+          python-version: 3.9
+
+      - name: Install python dependencies
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install tox pytest pytest-cov coverage responses
+          if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
+
+      - name: Tox testenv
+        run: |
+          tox
+
+      - name: Pytest
+        run: |
+          pytest
+
+      - name: Coveralls
+        uses: AndreMiras/coveralls-python-action@develop
+        with:
+          parallel: true
+          flag-name: Python Test Suite
+
+  coveralls_finish:
+    needs: tox-coveralls
+    runs-on: ubuntu-latest
+    steps:
+      - name: Coveralls Finished
+        uses: AndreMiras/coveralls-python-action@develop
+        with:
+          parallel-finished: true
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 55201e7..0039f46 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -3,20 +3,26 @@ repos:
     rev: 20.8b1
     hooks:
       - id: black
-        args: [ "--safe", "--diff", "--color" ]
+        args: [ "--safe", "--diff", "--color"]
+        verbose: true
+  - repo: https://github.com/psf/black
+    rev: 20.8b1
+    hooks:
+      - id: black
+        args: [ "--safe", "--quiet"]
         language_version: python3
   - repo: https://github.com/pycqa/isort
-    rev: 5.6.4
+    rev: 5.8.0
     hooks:
       - id: isort
         args: ["--profile", "black", "--filter-files"]
   - repo: https://github.com/asottile/blacken-docs
-    rev: v1.9.2
+    rev: v1.10.0
     hooks:
       - id: blacken-docs
         additional_dependencies: [ black==20.8b1 ]
   - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v3.4.0
+    rev: v4.0.1
     hooks:
       - id: check-docstring-first
       - id: trailing-whitespace
@@ -35,7 +41,7 @@ repos:
       - id: python-use-type-annotations
       - id: rst-backticks
   - repo: https://gitlab.com/pycqa/flake8
-    rev: 3.8.4
+    rev: 3.9.2
     hooks:
       - id: flake8
         language_version: python3
diff --git a/README.md b/README.md
index 2436b5f..1ad6593 100644
--- a/README.md
+++ b/README.md
@@ -3,6 +3,7 @@
 ShipEngine SDK - Python
 =======================
 ![GitHub Workflow Status](https://img.shields.io/github/workflow/status/ShipEngine/shipengine-python/Python%20package?label=shipengine-python&logo=github&logoColor=white)
+[![Coverage Status](https://coveralls.io/repos/github/ShipEngine/shipengine-python/badge.svg?branch=main)](https://coveralls.io/github/ShipEngine/shipengine-python?branch=main)
 ![OS Compatibility](https://shipengine.github.io/img/badges/os-badges.svg)
 > ATTN: This project is under development and not ready for consumer use.
 
diff --git a/poetry.lock b/poetry.lock
index f2f7c89..c1ff5ad 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -154,6 +154,39 @@ toml = {version = "*", optional = true, markers = "extra == \"toml\""}
 [package.extras]
 toml = ["toml"]
 
+[[package]]
+name = "coveralls"
+version = "3.1.0"
+description = "Show coverage stats online via coveralls.io"
+category = "dev"
+optional = false
+python-versions = ">= 3.5"
+
+[package.dependencies]
+coverage = ">=4.1,<6.0"
+docopt = ">=0.6.1"
+requests = ">=1.0.0"
+
+[package.extras]
+yaml = ["PyYAML (>=3.10)"]
+
+[[package]]
+name = "dataclasses-json"
+version = "0.5.3"
+description = "Easily serialize dataclasses to and from JSON"
+category = "main"
+optional = false
+python-versions = ">=3.6"
+
+[package.dependencies]
+marshmallow = ">=3.3.0,<4.0.0"
+marshmallow-enum = ">=1.5.1,<2.0.0"
+stringcase = "1.2.0"
+typing-inspect = ">=0.4.0"
+
+[package.extras]
+dev = ["pytest (>=6.2.3)", "ipython", "mypy (>=0.710)", "hypothesis", "portray", "flake8", "simplejson"]
+
 [[package]]
 name = "distlib"
 version = "0.3.1"
@@ -162,6 +195,14 @@ category = "dev"
 optional = false
 python-versions = "*"
 
+[[package]]
+name = "docopt"
+version = "0.6.2"
+description = "Pythonic argument parser, that will make you smile"
+category = "dev"
+optional = false
+python-versions = "*"
+
 [[package]]
 name = "docutils"
 version = "0.16"
@@ -221,7 +262,7 @@ python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
 
 [[package]]
 name = "importlib-metadata"
-version = "4.0.1"
+version = "4.2.0"
 description = "Read metadata from Python packages"
 category = "dev"
 optional = false
@@ -270,6 +311,31 @@ category = "dev"
 optional = false
 python-versions = ">=3.6"
 
+[[package]]
+name = "marshmallow"
+version = "3.12.1"
+description = "A lightweight library for converting complex datatypes to and from native Python datatypes."
+category = "main"
+optional = false
+python-versions = ">=3.5"
+
+[package.extras]
+dev = ["pytest", "pytz", "simplejson", "mypy (==0.812)", "flake8 (==3.9.2)", "flake8-bugbear (==21.4.3)", "pre-commit (>=2.4,<3.0)", "tox"]
+docs = ["sphinx (==4.0.0)", "sphinx-issues (==1.2.0)", "alabaster (==0.7.12)", "sphinx-version-warning (==1.1.2)", "autodocsumm (==0.2.4)"]
+lint = ["mypy (==0.812)", "flake8 (==3.9.2)", "flake8-bugbear (==21.4.3)", "pre-commit (>=2.4,<3.0)"]
+tests = ["pytest", "pytz", "simplejson"]
+
+[[package]]
+name = "marshmallow-enum"
+version = "1.5.1"
+description = "Enum field for Marshmallow"
+category = "main"
+optional = false
+python-versions = "*"
+
+[package.dependencies]
+marshmallow = ">=2.0.0"
+
 [[package]]
 name = "mccabe"
 version = "0.6.1"
@@ -298,7 +364,7 @@ python-versions = ">=3.6"
 name = "mypy-extensions"
 version = "0.4.3"
 description = "Experimental type system extensions for programs checked with the mypy typechecker."
-category = "dev"
+category = "main"
 optional = false
 python-versions = "*"
 
@@ -491,6 +557,22 @@ urllib3 = ">=1.21.1,<1.27"
 security = ["pyOpenSSL (>=0.14)", "cryptography (>=1.3.4)"]
 socks = ["PySocks (>=1.5.6,!=1.5.7)", "win-inet-pton"]
 
+[[package]]
+name = "responses"
+version = "0.13.3"
+description = "A utility library for mocking out the `requests` Python library."
+category = "dev"
+optional = false
+python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*"
+
+[package.dependencies]
+requests = ">=2.0"
+six = "*"
+urllib3 = ">=1.25.10"
+
+[package.extras]
+tests = ["coverage (>=3.7.1,<6.0.0)", "pytest-cov", "pytest-localserver", "flake8", "pytest (>=4.6,<5.0)", "pytest (>=4.6)", "mypy"]
+
 [[package]]
 name = "six"
 version = "1.16.0"
@@ -609,6 +691,14 @@ python-versions = ">=3.5"
 lint = ["flake8", "mypy", "docutils-stubs"]
 test = ["pytest"]
 
+[[package]]
+name = "stringcase"
+version = "1.2.0"
+description = "String case converter."
+category = "main"
+optional = false
+python-versions = "*"
+
 [[package]]
 name = "toml"
 version = "0.10.2"
@@ -656,18 +746,30 @@ category = "main"
 optional = false
 python-versions = "*"
 
+[[package]]
+name = "typing-inspect"
+version = "0.6.0"
+description = "Runtime inspection utilities for typing module."
+category = "main"
+optional = false
+python-versions = "*"
+
+[package.dependencies]
+mypy-extensions = ">=0.3.0"
+typing-extensions = ">=3.7.4"
+
 [[package]]
 name = "urllib3"
-version = "1.26.4"
+version = "1.26.5"
 description = "HTTP library with thread-safe connection pooling, file post, and more."
 category = "main"
 optional = false
 python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*, <4"
 
 [package.extras]
+brotli = ["brotlipy (>=0.6.0)"]
 secure = ["pyOpenSSL (>=0.14)", "cryptography (>=1.3.4)", "idna (>=2.0.0)", "certifi", "ipaddress"]
 socks = ["PySocks (>=1.5.6,!=1.5.7,<2.0)"]
-brotli = ["brotlipy (>=0.6.0)"]
 
 [[package]]
 name = "virtualenv"
@@ -724,7 +826,7 @@ testing = ["pytest (>=4.6)", "pytest-checkdocs (>=1.2.3)", "pytest-flake8", "pyt
 [metadata]
 lock-version = "1.1"
 python-versions = "^3.7"
-content-hash = "d7f6fec96cf7c4dbffe42d5a228cde1ad3e26587965fda8eac92b4f92b4bb202"
+content-hash = "d97d275553d9fb816a0b9191f3edf0a090c8d271d96a62e2cdbd60302e9a76f5"
 
 [metadata.files]
 aiohttp = [
@@ -867,10 +969,21 @@ coverage = [
     {file = "coverage-5.5-pp37-none-any.whl", hash = "sha256:2a3859cb82dcbda1cfd3e6f71c27081d18aa251d20a17d87d26d4cd216fb0af4"},
     {file = "coverage-5.5.tar.gz", hash = "sha256:ebe78fe9a0e874362175b02371bdfbee64d8edc42a044253ddf4ee7d3c15212c"},
 ]
+coveralls = [
+    {file = "coveralls-3.1.0-py2.py3-none-any.whl", hash = "sha256:172fb79c5f61c6ede60554f2cac46deff6d64ee735991fb2124fb414e188bdb4"},
+    {file = "coveralls-3.1.0.tar.gz", hash = "sha256:9b3236e086627340bf2c95f89f757d093cbed43d17179d3f4fb568c347e7d29a"},
+]
+dataclasses-json = [
+    {file = "dataclasses-json-0.5.3.tar.gz", hash = "sha256:fe17da934cfc4ec792ebe7e9a303434ecf4f5f8d8a7705acfbbe7ccbd34bf1ae"},
+    {file = "dataclasses_json-0.5.3-py3-none-any.whl", hash = "sha256:740e7b564d72ddaa0f66406b4ecb799447afda2799c1c425a4a76151bfcfda50"},
+]
 distlib = [
     {file = "distlib-0.3.1-py2.py3-none-any.whl", hash = "sha256:8c09de2c67b3e7deef7184574fc060ab8a793e7adbb183d942c389c8b13c52fb"},
     {file = "distlib-0.3.1.zip", hash = "sha256:edf6116872c863e1aa9d5bb7cb5e05a022c519a4594dc703843343a9ddd9bff1"},
 ]
+docopt = [
+    {file = "docopt-0.6.2.tar.gz", hash = "sha256:49b3a825280bd66b3aa83585ef59c4a8c82f2c8a522dbe754a8bc8d08c85c491"},
+]
 docutils = [
     {file = "docutils-0.16-py2.py3-none-any.whl", hash = "sha256:0c5b78adfbf7762415433f5515cd5c9e762339e23369dbe8000d84a4bf4ab3af"},
     {file = "docutils-0.16.tar.gz", hash = "sha256:c2de3a60e9e7d07be26b7f2b00ca0309c207e06c100f9cc2a94931fc75a478fc"},
@@ -896,8 +1009,8 @@ imagesize = [
     {file = "imagesize-1.2.0.tar.gz", hash = "sha256:b1f6b5a4eab1f73479a50fb79fcf729514a900c341d8503d62a62dbc4127a2b1"},
 ]
 importlib-metadata = [
-    {file = "importlib_metadata-4.0.1-py3-none-any.whl", hash = "sha256:d7eb1dea6d6a6086f8be21784cc9e3bcfa55872b52309bc5fad53a8ea444465d"},
-    {file = "importlib_metadata-4.0.1.tar.gz", hash = "sha256:8c501196e49fb9df5df43833bdb1e4328f64847763ec8a50703148b73784d581"},
+    {file = "importlib_metadata-4.2.0-py3-none-any.whl", hash = "sha256:057e92c15bc8d9e8109738a48db0ccb31b4d9d5cfbee5a8670879a30be66304b"},
+    {file = "importlib_metadata-4.2.0.tar.gz", hash = "sha256:b7e52a1f8dec14a75ea73e0891f3060099ca1d8e6a462a4dff11c3e119ea1b31"},
 ]
 isort = [
     {file = "isort-5.8.0-py3-none-any.whl", hash = "sha256:2bb1680aad211e3c9944dbce1d4ba09a989f04e238296c87fe2139faa26d655d"},
@@ -943,6 +1056,14 @@ markupsafe = [
     {file = "MarkupSafe-2.0.1-cp39-cp39-win_amd64.whl", hash = "sha256:693ce3f9e70a6cf7d2fb9e6c9d8b204b6b39897a2c4a1aa65728d5ac97dcc1d8"},
     {file = "MarkupSafe-2.0.1.tar.gz", hash = "sha256:594c67807fb16238b30c44bdf74f36c02cdf22d1c8cda91ef8a0ed8dabf5620a"},
 ]
+marshmallow = [
+    {file = "marshmallow-3.12.1-py2.py3-none-any.whl", hash = "sha256:b45cde981d1835145257b4a3c5cb7b80786dcf5f50dd2990749a50c16cb48e01"},
+    {file = "marshmallow-3.12.1.tar.gz", hash = "sha256:8050475b70470cc58f4441ee92375db611792ba39ca1ad41d39cad193ea9e040"},
+]
+marshmallow-enum = [
+    {file = "marshmallow-enum-1.5.1.tar.gz", hash = "sha256:38e697e11f45a8e64b4a1e664000897c659b60aa57bfa18d44e226a9920b6e58"},
+    {file = "marshmallow_enum-1.5.1-py2.py3-none-any.whl", hash = "sha256:57161ab3dbfde4f57adeb12090f39592e992b9c86d206d02f6bd03ebec60f072"},
+]
 mccabe = [
     {file = "mccabe-0.6.1-py2.py3-none-any.whl", hash = "sha256:ab8a6258860da4b6677da4bd2fe5dc2c659cff31b3ee4f7f5d64e79735b80d42"},
     {file = "mccabe-0.6.1.tar.gz", hash = "sha256:dd8d182285a0fe56bace7f45b5e7d1a6ebcbf524e8f3bd87eb0f125271b8831f"},
@@ -1128,6 +1249,10 @@ requests = [
     {file = "requests-2.25.1-py2.py3-none-any.whl", hash = "sha256:c210084e36a42ae6b9219e00e48287def368a26d03a048ddad7bfee44f75871e"},
     {file = "requests-2.25.1.tar.gz", hash = "sha256:27973dd4a904a4f13b263a19c866c13b92a39ed1c964655f025f3f8d3d75b804"},
 ]
+responses = [
+    {file = "responses-0.13.3-py2.py3-none-any.whl", hash = "sha256:b54067596f331786f5ed094ff21e8d79e6a1c68ef625180a7d34808d6f36c11b"},
+    {file = "responses-0.13.3.tar.gz", hash = "sha256:18a5b88eb24143adbf2b4100f328a2f5bfa72fbdacf12d97d41f07c26c45553d"},
+]
 six = [
     {file = "six-1.16.0-py2.py3-none-any.whl", hash = "sha256:8abb2f1d86890a2dfb989f9a77cfcfd3e47c2a354b01111771326f8aa26e0254"},
     {file = "six-1.16.0.tar.gz", hash = "sha256:1e61c37477a1626458e36f7b1d82aa5c9b094fa4802892072e49de9c60c4c926"},
@@ -1164,6 +1289,9 @@ sphinxcontrib-serializinghtml = [
     {file = "sphinxcontrib-serializinghtml-1.1.5.tar.gz", hash = "sha256:aa5f6de5dfdf809ef505c4895e51ef5c9eac17d0f287933eb49ec495280b6952"},
     {file = "sphinxcontrib_serializinghtml-1.1.5-py2.py3-none-any.whl", hash = "sha256:352a9a00ae864471d3a7ead8d7d79f5fc0b57e8b3f95e9867eb9eb28999b92fd"},
 ]
+stringcase = [
+    {file = "stringcase-1.2.0.tar.gz", hash = "sha256:48a06980661908efe8d9d34eab2b6c13aefa2163b3ced26972902e3bdfd87008"},
+]
 toml = [
     {file = "toml-0.10.2-py2.py3-none-any.whl", hash = "sha256:806143ae5bfb6a3c6e736a764057db0e6a0e05e338b5630894a5f779cabb4f9b"},
     {file = "toml-0.10.2.tar.gz", hash = "sha256:b3bda1d108d5dd99f4a20d24d9c348e91c4db7ab1b749200bded2f839ccbe68f"},
@@ -1209,9 +1337,14 @@ typing-extensions = [
     {file = "typing_extensions-3.10.0.0-py3-none-any.whl", hash = "sha256:779383f6086d90c99ae41cf0ff39aac8a7937a9283ce0a414e5dd782f4c94a84"},
     {file = "typing_extensions-3.10.0.0.tar.gz", hash = "sha256:50b6f157849174217d0656f99dc82fe932884fb250826c18350e159ec6cdf342"},
 ]
+typing-inspect = [
+    {file = "typing_inspect-0.6.0-py2-none-any.whl", hash = "sha256:de08f50a22955ddec353876df7b2545994d6df08a2f45d54ac8c05e530372ca0"},
+    {file = "typing_inspect-0.6.0-py3-none-any.whl", hash = "sha256:3b98390df4d999a28cf5b35d8b333425af5da2ece8a4ea9e98f71e7591347b4f"},
+    {file = "typing_inspect-0.6.0.tar.gz", hash = "sha256:8f1b1dd25908dbfd81d3bebc218011531e7ab614ba6e5bf7826d887c834afab7"},
+]
 urllib3 = [
-    {file = "urllib3-1.26.4-py2.py3-none-any.whl", hash = "sha256:2f4da4594db7e1e110a944bb1b551fdf4e6c136ad42e4234131391e21eb5b0df"},
-    {file = "urllib3-1.26.4.tar.gz", hash = "sha256:e7b021f7241115872f92f43c6508082facffbd1c048e3c6e2bb9c2a157e28937"},
+    {file = "urllib3-1.26.5-py2.py3-none-any.whl", hash = "sha256:753a0374df26658f99d826cfe40394a686d05985786d946fbe4165b5148f5a7c"},
+    {file = "urllib3-1.26.5.tar.gz", hash = "sha256:a7acd0977125325f516bda9735fa7142b909a8d01e8b2e4c8108d0984e6e0098"},
 ]
 virtualenv = [
     {file = "virtualenv-20.4.7-py2.py3-none-any.whl", hash = "sha256:2b0126166ea7c9c3661f5b8e06773d28f83322de7a3ff7d06f0aed18c9de6a76"},
diff --git a/pyproject.toml b/pyproject.toml
index 5036301..fc3d5df 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -12,6 +12,7 @@ python = "^3.7"
 aiohttp = "^3.7.4"
 requests = "^2.25.1"
 python-dotenv = "^0.15.0"
+dataclasses-json = "^0.5.3"
 
 [tool.poetry.dev-dependencies]
 pytest = "^4.6"
@@ -23,19 +24,21 @@ coverage = "^5.5"
 pytest-cov = "^2.11.1"
 pre-commit = "^2.11.0"
 isort = "^5.8.0"
+responses = "^0.13.3"
+coveralls = "^3.1.0"
 
 [tool.black]
 line-length = 100
 target-verstion = ["py37"]
 safe = true
-quiet = true
-diff = true
-color = true
 
 [tool.isort]
 profile = "black"
 multi_line_output = 3
 
+[tool.coverage.run]
+relative_files = true
+
 [tool.poetry.scripts]
 
 [build-system]
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..cc82309
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,18 @@
+aiohttp==3.7.4.post0; python_version >= "3.6"
+async-timeout==3.0.1; python_full_version >= "3.5.3" and python_version >= "3.6"
+attrs==21.2.0; python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.5.0" and python_version >= "3.6"
+certifi==2020.12.5; python_version >= "2.7" and python_full_version < "3.0.0" or python_full_version >= "3.5.0"
+chardet==4.0.0; python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.5.0" and python_version >= "3.6"
+dataclasses-json==0.5.3; python_version >= "3.6"
+idna==2.10; python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.5.0" and python_version >= "3.6"
+marshmallow==3.12.1; python_version >= "3.6"
+marshmallow-enum==1.5.1; python_version >= "3.6"
+multidict==5.1.0; python_version >= "3.6"
+mypy-extensions==0.4.3; python_version >= "3.6"
+python-dotenv==0.15.0
+requests==2.25.1; (python_version >= "2.7" and python_full_version < "3.0.0") or (python_full_version >= "3.5.0")
+stringcase==1.2.0; python_version >= "3.6"
+typing-extensions==3.10.0.0; python_version < "3.8" and python_version >= "3.6"
+typing-inspect==0.6.0; python_version >= "3.6"
+urllib3==1.26.5; python_version >= "2.7" and python_full_version < "3.0.0" or python_full_version >= "3.5.0" and python_version < "4"
+yarl==1.6.3; python_version >= "3.6"
diff --git a/shipengine_sdk/__init__.py b/shipengine_sdk/__init__.py
index 6edf480..6751847 100644
--- a/shipengine_sdk/__init__.py
+++ b/shipengine_sdk/__init__.py
@@ -6,7 +6,7 @@
 from logging import NullHandler
 
 # SDK imports here
-from shipengine_sdk.shipengine import ShipEngine
-from shipengine_sdk.shipengine_config import ShipEngineConfig
+from .shipengine import ShipEngine
+from .shipengine_config import ShipEngineConfig
 
 logging.getLogger(__name__).addHandler(NullHandler())
diff --git a/shipengine_sdk/errors/__init__.py b/shipengine_sdk/errors/__init__.py
index 8e77ec2..470f6c8 100644
--- a/shipengine_sdk/errors/__init__.py
+++ b/shipengine_sdk/errors/__init__.py
@@ -46,6 +46,9 @@ def _are_enums_valid(self):
                 f"Error type must be a member of ErrorCode enum - [{self.error_code}] provided."
             )
 
+    def to_dict(self):
+        return (lambda o: o.__dict__)(self)
+
     def to_json(self):
         return json.dumps(self, default=lambda o: o.__dict__, indent=2)
 
@@ -92,14 +95,15 @@ def __init__(
 
 
 class InvalidFieldValueError(ShipEngineError):
-    def __init__(self, field_name: str, reason: str, field_value) -> None:
+    def __init__(self, field_name: str, reason: str, field_value, source: str = None) -> None:
         """This error occurs when a field has been set to an invalid value."""
         self.field_name = field_name
         self.field_value = field_value
+        self.source = source
         super(InvalidFieldValueError, self).__init__(
             request_id=None,
-            message=f"{self.field_name} - {reason}",
-            source=None,
+            message=f"{self.field_name} - {reason} {self.field_value} was provided.",
+            source=self.source,
             error_type=ErrorType.VALIDATION.value,
             error_code=ErrorCode.INVALID_FIELD_VALUE.value,
         )
diff --git a/shipengine_sdk/http_client/__init__.py b/shipengine_sdk/http_client/__init__.py
index 0cb716b..96e8ffd 100644
--- a/shipengine_sdk/http_client/__init__.py
+++ b/shipengine_sdk/http_client/__init__.py
@@ -1 +1,2 @@
-"""Initial Docstring."""
+"""Synchronous HTTP Client for ShipEngine SDK."""
+from .client import ShipEngineClient
diff --git a/shipengine_sdk/http_client/client.py b/shipengine_sdk/http_client/client.py
index fa65d26..1fa5957 100644
--- a/shipengine_sdk/http_client/client.py
+++ b/shipengine_sdk/http_client/client.py
@@ -1 +1,125 @@
 """A Python library for ShipEngine API."""
+import json
+import os
+import platform
+from typing import Dict, Optional, Union
+
+import requests
+from requests import PreparedRequest, Request, RequestException, Response, Session
+from requests.adapters import HTTPAdapter
+from requests.auth import AuthBase
+from requests.packages.urllib3.util.retry import Retry
+
+from shipengine_sdk import __version__
+from shipengine_sdk.errors import ShipEngineError
+from shipengine_sdk.jsonrpc.process_request import handle_response, wrap_request
+from shipengine_sdk.models import ErrorCode, ErrorSource, ErrorType
+from shipengine_sdk.shipengine_config import ShipEngineConfig
+from shipengine_sdk.util.sdk_assertions import (
+    is_response_404,
+    is_response_429,
+    is_response_500,
+)
+
+
+class ShipEngineAuth(AuthBase):
+    def __init__(self, api_key: str) -> None:
+        """Auth Base appends `Api-Key` header to all requests."""
+        self.api_key = api_key
+
+    def __call__(self, request: Request, *args, **kwargs) -> Request:
+        request.headers["Api-Key"] = self.api_key
+        return request
+
+
+class ShipEngineClient:
+    _BASE_URI = ""
+
+    def __init__(self) -> None:
+        """"""
+        self.session = requests.session()
+
+    def send_rpc_request(
+        self, method: str, params: Optional[Dict[str, any]], retry: int, config: ShipEngineConfig
+    ) -> dict:
+        """
+        Send a `JSON-RPC 2.0` request via HTTP Messages to ShipEngine API. If the response
+         * is successful, the result is returned. Otherwise, an error is thrown.
+
+        TODO: add param and return docs
+        """
+        # TODO: debug the below base_uri variable to verify ternary logic works as intended.
+        client: Session = self._request_retry_session(retries=config.retries)
+        base_uri: Union[str, None] = (
+            config.base_uri
+            if os.getenv("CLIENT_BASE_URI") is None
+            else os.getenv("CLIENT_BASE_URI")
+        )
+
+        request_headers: dict = {
+            "User-Agent": self._derive_user_agent(),
+            "Content-Type": "application/json",
+            "Accept": "application/json",
+        }
+
+        request_body: dict = wrap_request(method=method, params=params)
+
+        req: Request = Request(
+            method="POST",
+            url=base_uri,
+            data=json.dumps(request_body),
+            headers=request_headers,
+            auth=ShipEngineAuth(config.api_key),
+        )
+        prepared_req: PreparedRequest = req.prepare()
+
+        try:
+            resp: Response = client.send(request=prepared_req, timeout=config.timeout)
+        except RequestException as err:
+            raise ShipEngineError(
+                message=f"An unknown error occurred while calling the ShipEngine {method} API:\n {err.response}",
+                source=ErrorSource.SHIPENGINE.value,
+                error_type=ErrorType.SYSTEM.value,
+                error_code=ErrorCode.UNSPECIFIED.value,
+            )
+
+        resp_body = resp.json()
+        status_code = resp.status_code
+
+        is_response_404(status_code=status_code, response_body=resp_body)
+        is_response_429(status_code=status_code, response_body=resp_body, config=config)
+        is_response_500(status_code=status_code, response_body=resp_body)
+
+        return handle_response(resp.json())
+
+    def _request_retry_session(
+        self, retries: int = 1, backoff_factor=1, status_force_list=(429, 500, 502, 503, 504)
+    ) -> Session:
+        """A requests `Session()` that has retries enforced."""
+        retry = Retry(
+            total=retries,
+            read=retries,
+            connect=retries,
+            backoff_factor=backoff_factor,
+            status_forcelist=status_force_list,
+        )
+        adapter = HTTPAdapter(max_retries=retry)
+        self.session.mount("http://", adapter=adapter)
+        self.session.mount("https://", adapter=adapter)
+        return self.session
+
+    @staticmethod
+    def _derive_user_agent() -> str:
+        """
+        Derive a User-Agent header from the environment. This is the user-agent that will
+        be set on every request via the ShipEngine Client.
+
+        :returns: A user-agent string that will be set in the `ShipEngineClient` request headers.
+        :rtype: str
+        """
+        sdk_version = f"shipengine-python/{__version__}"
+        os_kernel = platform.platform(terse=True)
+        python_version = platform.python_version()
+        python_implementation = platform.python_implementation()
+
+        return f"{sdk_version} {os_kernel} {python_version} {python_implementation}"
diff --git a/shipengine_sdk/jsonrpc/__init__.py b/shipengine_sdk/jsonrpc/__init__.py
new file mode 100644
index 0000000..351f26f
--- /dev/null
+++ b/shipengine_sdk/jsonrpc/__init__.py
@@ -0,0 +1,44 @@
+"""
+A collection of methods that provide `JSON-RPC 2.0` HTTP client
+functionality for sending HTTP requests from the ShipEngine SDK.
+"""
+import time
+from typing import Dict, Optional
+
+from shipengine_sdk.errors import RateLimitExceededError
+from shipengine_sdk.http_client import ShipEngineClient
+from shipengine_sdk.shipengine_config import ShipEngineConfig
+
+from .process_request import handle_response, wrap_request
+
+
+def rpc_request(
+    method: str, config: ShipEngineConfig, params: Optional[Dict[str, any]] = None
+) -> dict:
+    """
+    Create and send a `JSON-RPC 2.0` request over HTTP messages.
+    TODO: add param and return docs
+    """
+    return rpc_request_loop(method, params, config)
+
+
+def rpc_request_loop(method: str, params: dict, config: ShipEngineConfig) -> dict:
+    client = ShipEngineClient()
+    api_response = None
+    retry: int = 0
+    while retry <= config.retries:
+        try:
+            api_response = client.send_rpc_request(
+                method=method, params=params, retry=retry, config=config
+            )
+        except Exception as err:
+            if (
+                retry < config.retries
+                and type(err) is RateLimitExceededError
+                and err.retry_after < config.timeout
+            ):
+                time.sleep(err.retry_after)
+            else:
+                raise err
+        retry += 1
+        return api_response
diff --git a/shipengine_sdk/jsonrpc/process_request.py b/shipengine_sdk/jsonrpc/process_request.py
new file mode 100644
index 0000000..01bc16b
--- /dev/null
+++ b/shipengine_sdk/jsonrpc/process_request.py
@@ -0,0 +1,89 @@
+"""Functions that help with process requests and handle responses."""
+from typing import Dict, Optional
+from uuid import uuid4
+
+from shipengine_sdk.errors import (
+    AccountStatusError,
+    BusinessRuleError,
+    ClientSecurityError,
+    ClientSystemError,
+    ShipEngineError,
+    ValidationError,
+)
+from shipengine_sdk.models import ErrorType
+
+
+def wrap_request(method: str, params: Optional[Dict[str, any]]) -> dict:
+    """
+    Wrap request per `JSON-RPC 2.0` spec.
+
+    :param str method: The RPC Method to be sent to the RPC Server to
+    invoke a specific remote procedure.
+    :param params: The request data for the RPC request. This argument
+    is optional and can either be a dictionary or None.
+    :type params: Optional[Dict[str, any]]
+    """
+    if params is None:
+        return dict(id=f"req_{str(uuid4()).replace('-', '')}", jsonrpc="2.0", method=method)
+    else:
+        return dict(
+            id=f"req_{str(uuid4()).replace('-', '')}", jsonrpc="2.0", method=method, params=params
+        )
+
+
+def handle_response(response_body: dict) -> dict:
+    """Handles the response from ShipEngine API."""
+    if "result" in response_body:
+        return response_body
+
+    error = response_body["error"]
+    error_data = error["data"]
+    error_type = error_data["type"]
+    if error_type is ErrorType.ACCOUNT_STATUS.value:
+        raise AccountStatusError(
+            message=error["message"],
+            request_id=response_body["id"],
+            source=error_data["source"],
+            error_type=error_data["type"],
+            error_code=error_data["code"],
+        )
+    elif error_type is ErrorType.SECURITY.value:
+        raise ClientSecurityError(
+            message=error["message"],
+            request_id=response_body["id"],
+            source=error_data["source"],
+            error_type=error_data["type"],
+            error_code=error_data["code"],
+        )
+    elif error_type is ErrorType.VALIDATION.value:
+        raise ValidationError(
+            message=error["message"],
+            request_id=response_body["id"],
+            source=error_data["source"],
+            error_type=error_data["type"],
+            error_code=error_data["code"],
+        )
+    elif error_type is ErrorType.BUSINESS_RULES.value:
+        raise BusinessRuleError(
+            message=error["message"],
+            request_id=response_body["id"],
+            source=error_data["source"],
+            error_type=error_data["type"],
+            error_code=error_data["code"],
+        )
+    elif error_type is ErrorType.SYSTEM.value:
+        raise ClientSystemError(
+            message=error["message"],
+            request_id=response_body["id"],
+            source=error_data["source"],
+            error_type=error_data["type"],
+            error_code=error_data["code"],
+        )
+    else:
+        raise ShipEngineError(
+            message=error["message"],
+            request_id=response_body["id"],
+            source=error_data["source"],
+            error_type=error_data["type"],
+            error_code=error_data["code"],
+        )
diff --git a/shipengine_sdk/models/__init__.py b/shipengine_sdk/models/__init__.py
index ff6f842..c8d770b 100644
--- a/shipengine_sdk/models/__init__.py
+++ b/shipengine_sdk/models/__init__.py
@@ -1,4 +1,2 @@
 """ShipEngine SDK Models & Enumerations"""
-from shipengine_sdk.models.enums import ErrorCode
-from shipengine_sdk.models.enums import ErrorSource
-from shipengine_sdk.models.enums import ErrorType
+from shipengine_sdk.models.enums import ErrorCode, ErrorSource, ErrorType
diff --git a/shipengine_sdk/models/address/__init__.py b/shipengine_sdk/models/address/__init__.py
new file mode 100644
index 0000000..0aacafd
--- /dev/null
+++ b/shipengine_sdk/models/address/__init__.py
@@ -0,0 +1,32 @@
+"""Initial Docstring"""
+
+from dataclasses import dataclass
+from typing import List, Optional
+
+from dataclasses_json import LetterCase, dataclass_json
+
+
+@dataclass_json(letter_case=LetterCase.CAMEL)
+@dataclass
+class Address:
+    street: List[str]
+    city_locality: str
+    state_province: str
+    postal_code: str
+    country_code: str
+    is_residential: bool = False
+    name: str = ""
+    phone: str = ""
+    company: str = ""
+
+
+@dataclass_json(letter_case=LetterCase.CAMEL)
+@dataclass(frozen=True)
+class AddressValidateResult:
+    is_valid: Optional[bool]
+    request_id: str
+    normalized_address: Optional[Address]
+    messages: List
+    # info: List
+    # warnings: List
+    # errors: List
diff --git a/shipengine_sdk/models/enums/__init__.py b/shipengine_sdk/models/enums/__init__.py
index 9c1e29f..0d630fc 100644
--- a/shipengine_sdk/models/enums/__init__.py
+++ b/shipengine_sdk/models/enums/__init__.py
@@ -7,5 +7,16 @@
 
 
 class Endpoints(Enum):
+    """API Endpoint URI's used throughout the ShipEngine SDK."""
+
     TEST_RPC_URL = "https://simengine.herokuapp.com/jsonrpc"
     SHIPENGINE_RPC_URL = "https://api.shipengine.com/jsonrpc"
+
+
+class RPCMethods(Enum):
+    """A collection of RPC Methods used throughout the ShipEngine SDK."""
+
+    ADDRESS_VALIDATE = "address.validate.v1"
+    CREATE_TAG = "create.tag.v1"
+    LIST_CARRIERS = "carrier.listAccounts.v1"
+    TRACK_PACKAGE = "package.track.v1"
diff --git a/shipengine_sdk/services/__init__.py b/shipengine_sdk/services/__init__.py
index 0cb716b..a677db9 100644
--- a/shipengine_sdk/services/__init__.py
+++ b/shipengine_sdk/services/__init__.py
@@ -1 +1 @@
-"""Initial Docstring."""
+"""ShipEngine SDK service objects."""
diff --git a/shipengine_sdk/services/address_validation.py b/shipengine_sdk/services/address_validation.py
new file mode 100644
index 0000000..5f0bbec
--- /dev/null
+++ b/shipengine_sdk/services/address_validation.py
@@ -0,0 +1,33 @@
+"""Validate a single address or multiple addresses."""
+from shipengine_sdk.jsonrpc import rpc_request
+from shipengine_sdk.models.address import Address, AddressValidateResult
+from shipengine_sdk.models.enums import RPCMethods
+from shipengine_sdk.shipengine_config import ShipEngineConfig
+
+
+def validate(address: Address, config: ShipEngineConfig) -> AddressValidateResult:
+    """
+    Validate a single address via the `address/validate` remote procedure.
+
+    :param Address address: The address to be validate.
+    :param ShipEngineConfig config: The global ShipEngine configuration object.
+    :returns: :class:`AddressValidateResult`: The response from ShipEngine API including the
+    validated and normalized address.
+    """
+    api_response: dict = rpc_request(
+        method=RPCMethods.ADDRESS_VALIDATE.value,
+        config=config,
+        params={"address": address.to_dict()},
+    )
+    result = api_response["result"]
+    return AddressValidateResult(
+        is_valid=result["isValid"],
+        request_id=api_response["id"],
+        normalized_address=Address.from_dict(result["normalizedAddress"]),
+        messages=result["messages"],
+    )
+
+
+def normalize(address: Address, config: ShipEngineConfig) -> Address:
+    validation_result = validate(address=address, config=config)
+    return validation_result.normalized_address
diff --git a/shipengine_sdk/shipengine.py b/shipengine_sdk/shipengine.py
index 939a663..10bcb34 100644
--- a/shipengine_sdk/shipengine.py
+++ b/shipengine_sdk/shipengine.py
@@ -1,6 +1,8 @@
 """The entrypoint to the ShipEngine API SDK."""
-from typing import Dict
-from typing import Union
+from typing import Dict, Union
+
+from shipengine_sdk.models.address import Address, AddressValidateResult
+from shipengine_sdk.services.address_validation import validate
 
 from .shipengine_config import ShipEngineConfig
 
@@ -13,7 +15,7 @@ class ShipEngine:
     unless specifically overridden when calling a method.
     """
 
-    def __init__(self, config: Union[str, Dict[str, any]]) -> None:
+    def __init__(self, config: Union[str, Dict[str, any], ShipEngineConfig]) -> None:
         """
         Exposes the functionality of the ShipEngine API.
 
@@ -25,3 +27,17 @@ def __init__(self, config: Union[str, Dict[str, any]]) -> None:
             self.config = ShipEngineConfig({"api_key": config})
         elif type(config) is dict:
             self.config = ShipEngineConfig(config)
+
+    def validate_address(
+        self, address: Address, config: Union[Dict[str, any], ShipEngineConfig] = None
+    ) -> AddressValidateResult:
+        """
+        Validate an address in nearly any countryCode in the world.
+
+        :param Address address: The address to be validate.
+        :param ShipEngineConfig config: The global ShipEngine configuration object.
+        :returns: :class:`AddressValidateResult`: The response from ShipEngine API including the
+        validated and normalized address.
+        """
+        config = self.config.merge(new_config=config)
+        return validate(address, config)
diff --git a/shipengine_sdk/shipengine_config.py b/shipengine_sdk/shipengine_config.py
index 5c8418a..14af331 100644
--- a/shipengine_sdk/shipengine_config.py
+++ b/shipengine_sdk/shipengine_config.py
@@ -1,9 +1,10 @@
 """The global configuration object for the ShipEngine SDK."""
 import json
+from typing import Dict, Optional
 
 from shipengine_sdk.models.enums import Endpoints
-from shipengine_sdk.util import is_api_key_valid
-from shipengine_sdk.util import is_retries_less_than_zero
+from shipengine_sdk.util import is_api_key_valid, is_retries_valid
+from shipengine_sdk.util.sdk_assertions import is_timeout_valid
 
 
 class ShipEngineConfig:
@@ -28,6 +29,7 @@ def __init__(self, config: dict) -> None:
         is_api_key_valid(config)
         self.api_key = config["api_key"]
 
+        is_timeout_valid(config)
         if "timeout" in config:
             self.timeout = config["timeout"]
         else:
@@ -43,14 +45,14 @@ def __init__(self, config: dict) -> None:
         else:
             self.page_size = self.DEFAULT_PAGE_SIZE
 
-        is_retries_less_than_zero(config)
+        is_retries_valid(config)
         if "retries" in config:
             self.retries = config["retries"]
         else:
             self.retries = self.DEFAULT_RETRIES
         # TODO: add event listener to config object once it"s implemented.
 
-    def merge(self, new_config: dict = None):
+    def merge(self, new_config: Optional[Dict[str, any]] = None):
         """
         The method allows the merging of a method-level configuration
         adjustment into the current configuration.
@@ -84,5 +86,8 @@ def merge(self, new_config: dict = None):
 
             return ShipEngineConfig(config)
 
+    def to_dict(self):
+        return (lambda o: o.__dict__)(self)
+
     def to_json(self):
         return json.dumps(self, default=lambda o: o.__dict__, indent=2)
diff --git a/shipengine_sdk/util/__init__.py b/shipengine_sdk/util/__init__.py
index f77d2be..d321a47 100644
--- a/shipengine_sdk/util/__init__.py
+++ b/shipengine_sdk/util/__init__.py
@@ -1,6 +1,19 @@
-"""Initial Docstring"""
+"""Testing a string manipulation helper function."""
 from shipengine_sdk.util.sdk_assertions import (
     api_key_validation_error_assertions,
     is_api_key_valid,
-    is_retries_less_than_zero,
+    is_retries_valid,
 )
+
+
+def snake_to_camel(snake_case_string: str) -> str:
+    """
+    Takes in a `snake_case` string and returns a `camelCase` string.
+
+    :params str snake_case_string: The snake_case string to be converted
+    into camelCase.
+    :returns: camelCase string
+    :rtype: str
+    """
+    initial, *temp = snake_case_string.split("_")
+    return "".join([initial.lower(), *map(str.title, temp)])
diff --git a/shipengine_sdk/util/sdk_assertions.py b/shipengine_sdk/util/sdk_assertions.py
index 70857c4..fc2d4df 100644
--- a/shipengine_sdk/util/sdk_assertions.py
+++ b/shipengine_sdk/util/sdk_assertions.py
@@ -1,34 +1,144 @@
 """Assertion helper functions."""
-from shipengine_sdk.errors import InvalidFieldValueError, ValidationError
+import re
+
+from shipengine_sdk.errors import (
+    ClientSystemError,
+    ClientTimeoutError,
+    InvalidFieldValueError,
+    RateLimitExceededError,
+    ValidationError,
+)
 from shipengine_sdk.models import ErrorCode, ErrorSource, ErrorType
 
 
 def is_api_key_valid(config: dict) -> None:
-    """Check if API Key is set and is not empty or whitespace."""
+    """
+    Check if API Key is set and is not empty or whitespace.
+
+    :param dict config: The config dictionary passed into `ShipEngineConfig`.
+    :returns: None, only raises exceptions.
+    :rtype: None
+    """
+    message = "A ShipEngine API key must be specified."
     if "api_key" not in config or config["api_key"] == "":
         raise ValidationError(
-            message="A ShipEngine API key must be specified.",
+            message=message,
             source=ErrorSource.SHIPENGINE.value,
             error_type=ErrorType.VALIDATION.value,
             error_code=ErrorCode.FIELD_VALUE_REQUIRED.value,
         )
 
+    if re.match(r"\s", config["api_key"]):
+        raise ValidationError(
+            message=message,
+            source=ErrorSource.SHIPENGINE.value,
+            error_type=ErrorType.VALIDATION.value,
+            error_code=ErrorCode.FIELD_VALUE_REQUIRED.value,
+        )
 
-def is_retries_less_than_zero(config: dict) -> None:
-    """Checks that config.retries is less than zero."""
+
+def is_retries_valid(config: dict) -> None:
+    """
+    Checks that config.retries is a valid value.
+
+    :param dict config: The config dictionary passed into `ShipEngineConfig`.
+    :returns: None, only raises exceptions.
+    :rtype: None
+    """
     if "retries" in config and config["retries"] < 0:
         raise InvalidFieldValueError(
             field_name="retries",
             reason="Retries must be zero or greater.",
             field_value=config["retries"],
+            source=ErrorSource.SHIPENGINE.value,
+        )
+
+
+def is_timeout_valid(config: dict) -> None:
+    """
+    Checks that config.timeout is valid value.
+
+    :param dict config: The config dictionary passed into `ShipEngineConfig`.
+    :returns: None, only raises exceptions.
+    :rtype: None
+    """
+    if "timeout" in config and config["timeout"] < 0:
+        raise InvalidFieldValueError(
+            field_name="timeout",
+            reason="Timeout must be zero or greater.",
+            field_value=config["timeout"],
+            source=ErrorSource.SHIPENGINE.value,
         )
 
 
-def api_key_validation_error_assertions(e: ValidationError):
-    """Helper test function that has common assertions pertaining to ValidationErrors."""
-    assert type(e) is ValidationError
-    assert e.request_id is None
-    assert e.error_type is ErrorType.VALIDATION.value
-    assert e.error_code is ErrorCode.FIELD_VALUE_REQUIRED.value
-    assert e.source is ErrorSource.SHIPENGINE.value
-    assert e.message == "A ShipEngine API key must be specified."
+def api_key_validation_error_assertions(error) -> None:
+    """
+    Helper test function that has common assertions pertaining to ValidationErrors.
+
+    :param error: The error to execute assertions on.
+    :returns: None, only executes assertions.
+    :rtype: None
+    """
+    assert type(error) is ValidationError
+    assert error.request_id is None
+    assert error.error_type is ErrorType.VALIDATION.value
+    assert error.error_code is ErrorCode.FIELD_VALUE_REQUIRED.value
+    assert error.source is ErrorSource.SHIPENGINE.value
+    assert error.message == "A ShipEngine API key must be specified."
+
+
+def timeout_validation_error_assertions(error) -> None:
+    """Helper test function that has common assertions pertaining to InvalidFieldValueError."""
+    assert type(error) is InvalidFieldValueError
+    assert error.request_id is None
+    assert error.error_type is ErrorType.VALIDATION.value
+    assert error.error_code is ErrorCode.INVALID_FIELD_VALUE.value
+    assert error.source is ErrorSource.SHIPENGINE.value
+
+
+def is_response_404(status_code: int, response_body: dict) -> None:
+    """Check if status_code is 404 and raises an error if so."""
+    if "error" in response_body:
+        error = response_body["error"]
+        error_data = error["data"]
+        if status_code == 404:
+            raise ClientSystemError(
+                message=error["message"],
+                request_id=response_body["id"],
+                source=error_data["source"],
+                error_type=error_data["type"],
+                error_code=error_data["code"],
+            )
+
+
+def is_response_429(status_code: int, response_body: dict, config) -> None:
+    """Check if status_code is 429 and raises an error if so."""
+    if "error" in response_body and status_code == 429:
+        error = response_body["error"]
+        retry_after = error["data"]["retryAfter"]
+        if retry_after > config.timeout:
+            raise ClientTimeoutError(
+                retry_after=config.timeout,
+                source=ErrorSource.SHIPENGINE.value,
+                request_id=response_body["id"],
+            )
+        else:
+            raise RateLimitExceededError(
+                retry_after=retry_after,
+                source=ErrorSource.SHIPENGINE.value,
+                request_id=response_body["id"],
+            )
+
+
+def is_response_500(status_code: int, response_body: dict) -> None:
+    """Check if the status code is 500 and raises an error if so."""
+    if status_code == 500:
+        error = response_body["error"]
+        error_data = error["data"]
+        raise ClientSystemError(
+            message=error["message"],
+            request_id=response_body["id"],
+            source=error_data["source"],
+            error_type=error_data["type"],
+            error_code=error_data["code"],
+        )
diff --git a/tests/errors/test_errors.py b/tests/errors/test_errors.py
index d763ac6..4b5c51d 100644
--- a/tests/errors/test_errors.py
+++ b/tests/errors/test_errors.py
@@ -1,14 +1,16 @@
 """Tests for the ShipEngine SDK Errors"""
 import pytest
 
-from shipengine_sdk.errors import AccountStatusError
-from shipengine_sdk.errors import BusinessRuleError
-from shipengine_sdk.errors import ClientSecurityError
-from shipengine_sdk.errors import ClientTimeoutError
-from shipengine_sdk.errors import InvalidFieldValueError
-from shipengine_sdk.errors import RateLimitExceededError
-from shipengine_sdk.errors import ShipEngineError
-from shipengine_sdk.errors import ValidationError
+from shipengine_sdk.errors import (
+    AccountStatusError,
+    BusinessRuleError,
+    ClientSecurityError,
+    ClientTimeoutError,
+    InvalidFieldValueError,
+    RateLimitExceededError,
+    ShipEngineError,
+    ValidationError,
+)
 
 
 def shipengine_error():
diff --git a/tests/http_client/test_http_client.py b/tests/http_client/test_http_client.py
new file mode 100644
index 0000000..e7c0bfe
--- /dev/null
+++ b/tests/http_client/test_http_client.py
@@ -0,0 +1,48 @@
+"""Testing basic ShipEngineClient functionality."""
+import pytest
+import responses
+
+from shipengine_sdk import ShipEngine
+from shipengine_sdk.errors import ClientSystemError
+from shipengine_sdk.models.address import Address
+from shipengine_sdk.models.enums import Endpoints
+
+
+def get_500_server_error():
+    error_address = Address(
+        street=["500 Server Error"],
+        city_locality="Boston",
+        state_province="MA",
+        postal_code="02215",
+        country_code="US",
+    )
+    shipengine = ShipEngine(
+        dict(
+            api_key="baz",
+            base_uri=Endpoints.TEST_RPC_URL.value,
+            page_size=50,
+            retries=2,
+            timeout=10,
+        )
+    )
+    return shipengine.validate_address(error_address)
+
+
+@responses.activate
+def test_500_server_response():
+    responses.add(
+        responses.POST,
+        Endpoints.TEST_RPC_URL.value,
+        json={
+            "jsonrpc": "2.0",
+            "id": "req_DezVNUvRkAP819f3JeqiuS",
+            "error": {
+                "code": "-32603",
+                "message": "Unable to connect to the database",
+                "data": {"source": "shipengine", "type": "system", "code": "unspecified"},
+            },
+        },
+        status=500,
+    )
+    with pytest.raises(ClientSystemError):
+        get_500_server_error()
diff --git a/tests/services/test_address_validation.py b/tests/services/test_address_validation.py
new file mode 100644
index 0000000..e130959
--- /dev/null
+++ b/tests/services/test_address_validation.py
@@ -0,0 +1,55 @@
+"""Initial Docstring"""
+from shipengine_sdk import ShipEngine
+from shipengine_sdk.models.address import Address, AddressValidateResult
+from shipengine_sdk.models.enums import Endpoints
+
+
+def stub_config() -> dict:
+    """
+    Return a test configuration dictionary to be used
+    when instantiating the ShipEngine object.
+    """
+    return dict(
+        api_key="baz", base_uri=Endpoints.TEST_RPC_URL.value, page_size=50, retries=2, timeout=15
+    )
+
+
+def stub_shipengine_instance() -> ShipEngine:
+    """Return a test instance of the ShipEngine object."""
+    return ShipEngine(stub_config())
+
+
+def valid_residential_address() -> Address:
+    """
+    Return a test Address object with valid residential
+    address information.
+    """
+    return Address(
+        street=["4 Jersey St", "Apt. 2b"],
+        city_locality="Boston",
+        state_province="MA",
+        postal_code="02215",
+        country_code="US",
+    )
+
+
+class TestValidateAddress:
+    def test_valid_residential_address(self):
+        """DX-1024 - Valid residential address"""
+        shipengine = stub_shipengine_instance()
+        valid_address = valid_residential_address()
+        validated_address = shipengine.validate_address(valid_address)
+        address = validated_address.normalized_address
+
+        assert type(validated_address) is AddressValidateResult
+        assert validated_address.is_valid is True
+        assert address is not None
+        assert (
+            address.street[0]
+            == (valid_address.street[0] + " " + valid_address.street[1]).replace(".", "").upper()
+        )
+        assert address.city_locality == valid_address.city_locality.upper()
+        assert address.state_province == valid_address.state_province.upper()
+        assert address.postal_code == valid_address.postal_code
+        assert address.country_code == valid_address.country_code.upper()
+        assert address.is_residential is True
diff --git a/tests/test___init__.py b/tests/test___init__.py
new file mode 100644
index 0000000..b2f5f60
--- /dev/null
+++ b/tests/test___init__.py
@@ -0,0 +1,8 @@
+"""Initial Docstring"""
+from shipengine_sdk.util import snake_to_camel
+
+
+class TestSnakeToCamelCase:
+    def test_snake_to_camel(self):
+        camel_case = snake_to_camel("python_is_awesome")
+        assert camel_case == "pythonIsAwesome"
diff --git a/tests/test_shipengine.py b/tests/test_shipengine.py
index efc5b85..9d549dc 100644
--- a/tests/test_shipengine.py
+++ b/tests/test_shipengine.py
@@ -6,19 +6,19 @@
 from shipengine_sdk.util.sdk_assertions import api_key_validation_error_assertions
 
 
-def shipengine_no_api_key():
+def shipengine_no_api_key() -> ShipEngine:
     """Return an error from no API Key."""
     return ShipEngine(dict(retries=2))
 
 
-def shipengine_empty_api_key():
+def shipengine_empty_api_key() -> ShipEngine:
     """Return an error from empty API Key."""
     return ShipEngine(config="")
 
 
-def shipengine_whitespace_in_api_key():
+def shipengine_whitespace_in_api_key() -> ShipEngine:
     """Return an error from whitespace in API Key."""
-    return ShipEngine(config=" ")
+    return ShipEngine(config="  ")
 
 
 class TestShipEngine:
@@ -30,7 +30,7 @@ def test_no_api_key_provided(self) -> None:
         """DX-1440 - No API Key at instantiation."""
         try:
             shipengine_no_api_key()
-        except ValidationError as e:
+        except Exception as e:
             with pytest.raises(ValidationError):
                 shipengine_no_api_key()
             api_key_validation_error_assertions(e)
@@ -39,7 +39,7 @@ def test_empty_api_key_provided(self) -> None:
         """DX-1441 - Empty API Key at instantiation."""
         try:
             shipengine_empty_api_key()
-        except ValidationError as e:
+        except Exception as e:
             with pytest.raises(ValidationError):
                 shipengine_empty_api_key()
             api_key_validation_error_assertions(e)
diff --git a/tests/test_shipengine_config.py b/tests/test_shipengine_config.py
index cabc6e2..562dd5f 100644
--- a/tests/test_shipengine_config.py
+++ b/tests/test_shipengine_config.py
@@ -1,32 +1,115 @@
 """Testing the ShipEngineConfig object."""
 import pytest
 
-from shipengine_sdk import ShipEngineConfig
-from shipengine_sdk.errors import ValidationError
+from shipengine_sdk import ShipEngine, ShipEngineConfig
+from shipengine_sdk.errors import InvalidFieldValueError, ValidationError
+from shipengine_sdk.models.address import Address
+from shipengine_sdk.models.enums import Endpoints
 from shipengine_sdk.util import api_key_validation_error_assertions
+from shipengine_sdk.util.sdk_assertions import timeout_validation_error_assertions
 
 
-def config_with_no_api_key():
+def stub_config() -> dict:
+    """
+    Return a test configuration dictionary to be used
+    when instantiating the ShipEngine object.
+    """
+    return dict(
+        api_key="baz", base_uri=Endpoints.TEST_RPC_URL.value, page_size=50, retries=2, timeout=15
+    )
+
+
+def valid_residential_address() -> Address:
+    """
+    Return a test Address object with valid residential
+    address information.
+    """
+    return Address(
+        street=["4 Jersey St", "Apt. 2b"],
+        city_locality="Boston",
+        state_province="MA",
+        postal_code="02215",
+        country_code="US",
+    )
+
+
+def config_with_no_api_key() -> ShipEngineConfig:
     """Return an error from no API Key."""
     return ShipEngineConfig(dict(retries=2))
 
 
-def config_with_empty_api_key():
+def config_with_empty_api_key() -> ShipEngineConfig:
     """Return an error from empty API Key."""
     return ShipEngineConfig(dict(api_key=""))
 
 
-def config_with_whitespace_in_api_key():
+def config_with_whitespace_in_api_key() -> ShipEngineConfig:
     """Return an error from whitespace in API Key."""
     return ShipEngineConfig(dict(api_key=" "))
 
 
+def set_config_timeout(timeout: int) -> ShipEngineConfig:
+    """
+    Return an error from an invalid timeout value being passed in or
+    returns the successfully created `ShipEngineConfig` object if valid
+    configuration values are passed in.
+
+    :param int timeout: The timeout to be passed into the `ShipEngineConfig` object.
+    :returns: :class:`ShipEngineConfig`: Global configuration object for the ShipEngine SDK.
+    :raises: :class:`InvalidFieldValueError`: If invalid value is passed into `ShipEngineConfig`
+    object at instantiation.
+    """
+    return ShipEngineConfig(dict(api_key="baz", timeout=timeout))
+
+
+def set_config_retries(retries: int) -> ShipEngineConfig:
+    """
+    Return a ShipEngineConfig object with the set retries and
+    API Key, where the rest of the configuration values are
+    the default values.
+
+    :param int retries: The retries to be passed into the `ShipEngineConfig` object.
+    :returns: :class:`ShipEngineConfig`: Global configuration object for the ShipEngine SDK.
+    :raises: :class:`InvalidFieldValueError`: If invalid value is passed into `ShipEngineConfig`
+    object at instantiation.
+    """
+    return ShipEngineConfig(dict(api_key="baz", retries=retries))
+
+
+def complete_valid_config() -> ShipEngineConfig:
+    """
+    Return a `ShipEngineConfig` object that has valid custom
+    values passed in.
+    """
+    return ShipEngineConfig(
+        dict(
+            api_key="baz",
+            base_uri=Endpoints.TEST_RPC_URL.value,
+            page_size=50,
+            retries=2,
+            timeout=10,
+        )
+    )
+
+
 class TestShipEngineConfig:
+    def test_valid_custom_config(self):
+        """
+        Test case where a config object has been passed custom
+        valid values for each attribute.
+        """
+        valid_config: ShipEngineConfig = complete_valid_config()
+        assert valid_config.api_key == "baz"
+        assert valid_config.base_uri is Endpoints.TEST_RPC_URL.value
+        assert valid_config.page_size == 50
+        assert valid_config.retries == 2
+        assert valid_config.timeout == 10
+
     def test_no_api_key_provided(self) -> None:
         """DX-1440 - No API Key at instantiation"""
         try:
             config_with_no_api_key()
-        except ValidationError as e:
+        except Exception as e:
             api_key_validation_error_assertions(e)
             with pytest.raises(ValidationError):
                 config_with_no_api_key()
@@ -35,7 +118,77 @@ def test_empty_api_key_provided(self) -> None:
         """DX-1441 - Empty API Key at instantiation."""
         try:
             config_with_empty_api_key()
-        except ValidationError as e:
+        except Exception as e:
             api_key_validation_error_assertions(e)
             with pytest.raises(ValidationError):
                 config_with_empty_api_key()
+
+    def test_valid_retries(self):
+        """Test case where a valid value is passed in for the retries."""
+        retries = 2
+        valid_retries = set_config_retries(retries)
+        assert valid_retries.api_key == "baz"
+        assert valid_retries.retries == retries
+
+    def test_invalid_retries_provided(self):
+        """DX-1442 - Invalid retries at instantiation."""
+        retries = -3
+        try:
+            set_config_retries(retries)
+        except InvalidFieldValueError as e:
+            timeout_validation_error_assertions(e)
+            assert (
+                e.message == f"retries - Retries must be zero or greater. {retries} was provided."
+            )
+            with pytest.raises(InvalidFieldValueError):
+                set_config_retries(retries)
+
+    def test_invalid_timeout_provided(self):
+        """DX-1443 - Invalid timeout at instantiation."""
+        timeout = -5
+        try:
+            set_config_timeout(timeout)
+        except InvalidFieldValueError as e:
+            timeout_validation_error_assertions(e)
+            assert (
+                e.message == f"timeout - Timeout must be zero or greater. {timeout} was provided."
+            )
+
+    def test_invalid_timeout_in_method_call(self):
+        """DX-1447 - Invalid timeout in method call configuration."""
+        timeout = -5
+        try:
+            shipengine = ShipEngine(stub_config())
+            shipengine.validate_address(
+                address=valid_residential_address(), config=dict(timeout=timeout)
+            )
+        except InvalidFieldValueError as e:
+            timeout_validation_error_assertions(e)
+            assert (
+                e.message == f"timeout - Timeout must be zero or greater. {timeout} was provided."
+            )
+
+    def test_invalid_retries_in_method_call(self):
+        """DX-1446 - Invalid retries in method call configuration."""
+        retries = -5
+        try:
+            shipengine = ShipEngine(stub_config())
+            shipengine.validate_address(
+                address=valid_residential_address(), config=dict(retries=retries)
+            )
+        except InvalidFieldValueError as e:
+            timeout_validation_error_assertions(e)
+            assert (
+                e.message == f"retries - Retries must be zero or greater. {retries} was provided."
+            )
+
+    def test_invalid_api_key_in_method_call(self):
+        """DX-1445 - Invalid api_key in method call configuration."""
+        api_key = "   "
+        try:
+            shipengine = ShipEngine(stub_config())
+            shipengine.validate_address(
+                address=valid_residential_address(), config=dict(api_key=api_key)
+            )
+        except Exception as e:
+            api_key_validation_error_assertions(e)
diff --git a/tox.ini b/tox.ini
index 75091d6..114a92e 100644
--- a/tox.ini
+++ b/tox.ini
@@ -17,22 +17,34 @@ basepython = python3.7
 
 [testenv]
 description = run tests with pytest under {basepython}
+passenv =
+    GITHUB_TOKEN
+    GITHUB_ACTION
+    GITHUB_REPOSITORY
+    GITHUB_RUN_ID
 setenv =
     PIP_DISABLE_PIP_VERSION_CHECK = 1
     COVERAGE_FILE = {env:COVERAGE_FILE:{toxworkdir}/.coverage.{envname}}
+    COVERALLS_REPO_TOKEN = GITHUB_TOKEN
 changedir = tests
 deps =
     pytest
     pytest-cov
     flake8
     coverage
+    coveralls
+    responses
 commands =
     pytest {posargs:}
+;    coveralls --submit={toxworkdir}/.coverage.{envname}
 
 [testenv:lint]
 skip_install = True
 deps = pre-commit>=2.9.3
-commands = pre-commit run --all-files --show-diff-on-failure {posargs:}
+commands = pre-commit run --show-diff-on-failure {posargs:}
+
+[coverage:run]
+relative_files = True
 
 [flake8]
 max-line-length = 100
@@ -40,6 +52,8 @@ per-file-ignores =
     ; imported but unused
     __init__.py: F401
 extend-ignore =
+    ; line break before binary operator
+    W503
     ; whitespace before ':'
     E203
     ; Missing Docstrings