diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..5c47f76
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,9 @@
+/.gitattributes export-ignore
+/.gitignore export-ignore
+/.travis.yml export-ignore
+/appveyor.yml export-ignore
+/CHANGELOG.md export-ignore
+/phpcs.xml.dist export-ignore
+/phpunit.xml.dist export-ignore
+/README.md export-ignore
+/tests export-ignore
diff --git a/.travis.yml b/.travis.yml
index 5f97515..38b521b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -14,15 +14,6 @@ matrix:
       php: '7.3'
       env: require=1 dependencies=highest
 
-    - name: '[CS] PHP 7.2 With Locked Dependencies'
-      php: '7.2'
-      env: cs=1
-    - name: '[CS] PHP 7.2 With Lowest Dependencies'
-      php: '7.2'
-      env: cs=1 dependencies=lowest
-    - name: '[CS] PHP 7.2 With Highest Dependencies'
-      php: '7.2'
-      env: cs=1 dependencies=highest
     - name: '[CS] PHP 7.3 With Locked Dependencies'
       php: '7.3'
       env: cs=1
@@ -38,34 +29,28 @@ matrix:
     - name: '[CS] PHP Nightly With Lowest Dependencies'
       php: nightly
       env: cs=1 dependencies=lowest
-    - name: '[CS] PHP Nightly With HIghest Dependencies'
+    - name: '[CS] PHP Nightly With Highest Dependencies'
       php: nightly
       env: cs=1 dependencies=highest
 
-    - name: '[UNIT] PHP 7.2 With Locked Dependencies'
-      php: '7.2'
-    - name: '[UNIT] PHP 7.2 With Lowest Dependencies'
-      php: '7.2'
-      env: dependencies=lowest
-    - name: '[UNIT] PHP 7.2 With Highest Dependencies'
-      php: '7.2'
-      env: dependencies=highest
     - name: '[UNIT] PHP 7.3 With Locked Dependencies'
       php: '7.3'
+      env: unit=1
     - name: '[UNIT] PHP 7.3 With Lowest Dependencies'
       php: '7.3'
-      env: dependencies=lowest
+      env: dependencies=lowest unit=1
     - name: '[UNIT] PHP 7.3 With Highest Dependencies'
       php: '7.3'
-      env: dependencies=highest
+      env: dependencies=highest unit=1
     - name: '[UNIT] PHP Nightly With Locked Dependencies'
       php: nightly
+      env: unit=1
     - name: '[UNIT] PHP Nightly With Highest Dependencies'
       php: nightly
-      env: dependencies=lowest
+      env: dependencies=highest unit=1
     - name: '[UNIT] PHP Nightly With Lowest Dependencies'
       php: nightly
-      env: dependencies=highest
+      env: dependencies=lowest unit=1
   allow_failures:
     - name: '[CS] PHP Nightly With Locked Dependencies'
       php: nightly
@@ -73,36 +58,41 @@ matrix:
     - name: '[CS] PHP Nightly With Lowest Dependencies'
       php: nightly
       env: cs=1 dependencies=lowest
-    - name: '[CS] PHP Nightly With HIghest Dependencies'
+    - name: '[CS] PHP Nightly With Highest Dependencies'
       php: nightly
       env: cs=1 dependencies=highest
 
     - name: '[UNIT] PHP Nightly With Locked Dependencies'
       php: nightly
+      env: unit=1
     - name: '[UNIT] PHP Nightly With Highest Dependencies'
       php: nightly
-      env: dependencies=lowest
+      env: dependencies=highest unit=1
     - name: '[UNIT] PHP Nightly With Lowest Dependencies'
       php: nightly
-      env: dependencies=highest
+      env: dependencies=lowest unit=1
+
+services:
+  - redis-server
 
 before_install:
-- phpenv config-rm xdebug.ini || echo "No xdebug config."
-- composer self-update
+  - phpenv config-rm xdebug.ini || echo "No xdebug config."
+  - composer self-update
 
 install:
-- wget https://github.com/php-coveralls/php-coveralls/releases/download/v2.0.0/php-coveralls.phar
-- chmod +x php-coveralls.phar
+  - wget https://github.com/php-coveralls/php-coveralls/releases/download/v2.0.0/php-coveralls.phar
+  - chmod +x php-coveralls.phar
 
 before_script:
-  - if [ -z "$dependencies" ]; then travis_retry composer install --no-scripts; fi;
-  - if [ "$dependencies" = "lowest" ]; then travis_retry composer update --no-scripts --prefer-lowest -n; fi;
-  - if [ "$dependencies" = "highest" ]; then travis_retry composer update --no-scripts -n; fi;
+  - if [ -z "$dependencies" ]; then travis_retry composer install -n; fi;
+  - if [ "$dependencies" = "lowest" ]; then travis_retry composer update --prefer-lowest -n; fi;
+  - if [ "$dependencies" = "highest" ]; then travis_retry composer update -n; fi;
 
 script:
-  - if [ -z "$cs" ] && [ -z "$require" ]; then phpdbg -qrr vendor/bin/phpunit --coverage-text --coverage-clover build/logs/clover.xml; fi;
+  - if [ "$unit" = 1 ]; then phpdbg -qrr vendor/bin/phpunit --testsuite HarmonIOHttpClientUnitTestSuite --coverage-text --coverage-clover build/logs/clover.xml; fi;
+  - if [ "$integration" = 1 ]; then phpdbg -qrr vendor/bin/phpunit --testsuite HarmonIOHttpClientIntegrationTestSuite --coverage-text --coverage-clover build/logs/clover.xml; fi;
   - if [ "$cs" = 1 ]; then vendor/bin/phpcs -s; fi;
   - if [ "$require" = 1 ]; then vendor/bin/composer-require-checker check; fi;
 
 after_success:
-  - if [ -z "$cs" ] && [ -z "$require" ]; then travis_retry php php-coveralls.phar; fi;
+  - if [ "$unit" = 1 ]; then travis_retry php php-coveralls.phar; fi;
diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..db91510
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,32 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased] - 0000-00-00
+
+### Added
+
+*None*
+
+### Changed
+
+*None*
+
+### Deprecated
+
+*None*
+
+### Removed
+
+*None*
+
+### Fixed
+
+*None*
+
+### Security
+
+*None*
diff --git a/README.md b/README.md
index d8213ca..e431730 100644
--- a/README.md
+++ b/README.md
@@ -5,3 +5,137 @@
 [![Build status](https://ci.appveyor.com/api/projects/status/qe3volxj5pxqaguu/branch/master?svg=true)](https://ci.appveyor.com/project/PeeHaa/http-client/branch/master)
 [![Coverage Status](https://coveralls.io/repos/github/HarmonyIO/Http-Client/badge.svg?branch=master)](https://coveralls.io/github/HarmonyIO/Http-Client?branch=master)
 [![License](https://poser.pugx.org/harmonyio/http-client/license)](https://packagist.org/packages/harmonyio/http-client)
+
+Async caching aware http client
+
+## Requirements
+
+- PHP 7.3
+- Redis (if wanting to use the Redis caching provider)
+
+In addition for non-blocking context one of the following event libraries should be installed:
+
+- [ev](https://pecl.php.net/package/ev)
+- [event](https://pecl.php.net/package/event)
+- [php-uv](https://github.com/bwoebi/php-uv)
+
+## Installation
+
+```
+composer require harmonyio/http-client
+```
+
+## Usage
+
+### Caching requests
+
+The following example shows how to make a request and cache the result so consecutive calls will used the cached results instead of making a new external HTTP call.
+
+```php
+<?php declare(strict_types=1);
+
+namespace Foo;
+
+use Amp\Artax\DefaultClient;
+use Amp\Redis\Client;
+use HarmonyIO\Cache\Provider\Redis;
+use HarmonyIO\Cache\Ttl;
+use HarmonyIO\HttpClient\Client\ArtaxClient;
+use HarmonyIO\HttpClient\Message\CachingRequest;
+use function Amp\wait;
+
+// create instance of the HTTP client
+$httpClient = new ArtaxClient(
+    new DefaultClient(),
+    new Redis(new Client('tcp://127.0.0.1:6379'))
+);
+
+// create a new request to be cached for 10 seconds
+$request = new CachingRequest('TestRequestKey', new Ttl(10), 'https://httpbin.org/get');
+
+// make the request and cache it
+$result = wait($httpClient->request($request));
+
+// all consecutive requests will now used the cached result instead of calling the external service again
+$result = wait($httpClient->request($request));
+```
+
+### Non-caching requests
+
+It is also possible to make non-caching requests.
+
+```php
+<?php declare(strict_types=1);
+
+namespace Foo;
+
+use Amp\Artax\DefaultClient;
+use Amp\Redis\Client;
+use HarmonyIO\Cache\Provider\Redis;
+use HarmonyIO\HttpClient\Client\ArtaxClient;
+use HarmonyIO\HttpClient\Message\Request;
+use function Amp\wait;
+
+// create instance of the HTTP client
+$httpClient = new ArtaxClient(
+    new DefaultClient(),
+    new Redis(new Client('tcp://127.0.0.1:6379'))
+);
+
+// create a new request to be cached for 10 seconds
+$request = new Request('https://httpbin.org/get');
+
+// make the request (the results will NOT be cache)
+$result = wait($httpClient->request($request));
+
+// make the same request again
+$result = wait($httpClient->request($request));
+```
+
+## Client interface
+
+The HTTP client's interface only contains a single method: `Client::request(\HarmonyIO\HttpClient\Message\Request $request)`.
+
+The `$request` parameter can be either a "normal" non-caching request (`HarmonyIO\HttpClient\Message\Request`) or a caching request (`HarmonyIO\HttpClient\Message\CachingRequest`).
+
+### `HarmonyIO\HttpClient\Message\Request`
+
+The constructor of the request class expects at least a URL to make the request to and optionally an HTTP method (defaults to GET).
+
+Optional request parts can be set in setter method of the request class:
+
+```php
+<?php declare(strict_types=1);
+
+namespace Foo;
+
+use HarmonyIO\HttpClient\Message\Request;
+
+$request = (new Request('https://httpbin.org/post', 'POST'))
+    ->setProtocolVersions('1.1', '2.0')
+    ->addHeader('foo', 'bar')
+    ->addHeader('baz', 'qux')
+    ->setBody('foobar')
+;
+```
+
+### `HarmonyIO\HttpClient\Message\CachingRequest`
+
+The constructor of the caching request class expects at least a key, a TTL, the URL to make the request to and optionally an HTTP method (defaults to GET).
+
+Optional request parts can be set in setter method of the request class as defined in the previous section.
+
+```php
+<?php declare(strict_types=1);
+
+namespace Foo;
+
+use HarmonyIO\Cache\Ttl;
+use HarmonyIO\HttpClient\Message\CachingRequest;
+
+$request = (new CachingRequest('UniqueCachingKey', new Ttl(Ttl::ONE_HOUR), 'https://httpbin.org/get'))
+    ->setProtocolVersions('1.1', '2.0')
+    ->addHeader('foo', 'bar')
+    ->addHeader('baz', 'qux')
+;
+```
diff --git a/appveyor.yml b/appveyor.yml
index 988b253..cc0d349 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -1,55 +1,72 @@
 build: false
-
+clone_folder: c:\projects\http_client
+clone_depth: 1
 platform:
   - x64
-
-clone_folder: c:\projects\php-project-workspace
-
-## Build matrix for lowest and highest possible targets
 environment:
   matrix:
-  - dependencies: current
-    php_ver_target: 7.2
-  - dependencies: lowest
-    php_ver_target: 7.2
-  - dependencies: highest
-    php_ver_target: 7.2
+    - dependencies: current
+      php_ver_target: 7.3
+    - dependencies: lowest
+      php_ver_target: 7.3
+    - dependencies: highest
+      php_ver_target: 7.3
 
-## Cache composer, chocolatey and php bits
+  project_directory: c:\projects\http_client
+  composer_directory: c:\tools\composer
+  composer_executable: c:\tools\composer\composer.phar
+  composer_installer: c:\tools\composer\installer.php
+  php_directory: c:\tools\php
 cache:
-    - '%LOCALAPPDATA%\Composer\files -> composer.lock'
-    - composer.phar
-    - C:\ProgramData\chocolatey\bin -> .appveyor.yml
-    - C:\ProgramData\chocolatey\lib -> .appveyor.yml
-    - c:\tools\php -> .appveyor.yml
-
-## Set up environment varriables
+  - c:\ProgramData\chocolatey\bin -> appveyor.yml
+  - c:\ProgramData\chocolatey\lib -> appveyor.yml
+  - c:\tools\composer -> appveyor.yml
+  - '%LOCALAPPDATA%\Composer -> appveyor.yml'
+  - c:\tools\php -> appveyor.yml
 init:
-    - SET PATH=C:\Program Files\OpenSSL;c:\tools\php;%PATH%
-    - SET COMPOSER_NO_INTERACTION=1
-    - SET PHP=1
-    - SET ANSICON=121x90 (121x90)
-
-## Install PHP and composer, and run the appropriate composer command
+  - ps: $Env:PATH = $Env:php_directory + ';' + $Env:composer_directory + ';' + $Env:PATH
+  - SET PATH=C:\Program Files\OpenSSL;%PATH%
+  - SET COMPOSER_NO_INTERACTION=1
+  - SET PHP=1
+  - SET ANSICON=121x90 (121x90)
 install:
-    - IF EXIST c:\tools\php (SET PHP=0)
-    - ps: appveyor-retry cinst --params '""/InstallDir:C:\tools\php""' --ignore-checksums -y php --version ((choco search php --exact --all-versions -r | select-string -pattern $env:php_ver_target | sort { [version]($_ -split '\|' | select -last 1) } -Descending | Select-Object -first 1) -replace '[php|]','')
-    - cd c:\tools\php
-    - IF %PHP%==1 copy php.ini-production php.ini /Y
-    - IF %PHP%==1 echo date.timezone="UTC" >> php.ini
-    - IF %PHP%==1 echo extension_dir=ext >> php.ini
-    - IF %PHP%==1 echo extension=php_openssl.dll >> php.ini
-    - IF %PHP%==1 echo extension=php_mbstring.dll >> php.ini
-    - IF %PHP%==1 echo extension=php_fileinfo.dll >> php.ini
-    - IF %PHP%==1 echo @php %%~dp0composer.phar %%* > composer.bat
-    - appveyor-retry appveyor DownloadFile https://getcomposer.org/composer.phar
-    - cd c:\projects\php-project-workspace
-    - IF %dependencies%==lowest appveyor-retry composer update --no-scripts --prefer-lowest --no-progress --profile -n
-    - IF %dependencies%==current appveyor-retry composer install --no-scripts --no-progress --profile
-    - IF %dependencies%==highest appveyor-retry composer update --no-scripts --no-progress --profile -n
-    - composer show
+  # Install Redis
+  - nuget install redis-64 -excludeversion
+  - redis-64\tools\redis-server.exe --service-install
+  - redis-64\tools\redis-server.exe --service-start
+
+  # Install PHP
+  - ps: If ((Test-Path $Env:php_directory) -eq $False) { New-Item -Path $Env:php_directory -ItemType 'directory' }
+  - ps: $php_install_parameters = '"/DontAddToPath /InstallDir:' + $Env:php_directory + '"'
+  - ps: appveyor-retry choco upgrade php --yes --version=$Env:exact_php_version --params=$php_install_parameters
+
+  # Prepare PHP
+  - ps: cd $Env:php_directory
+  - ps: Copy-Item php.ini-production -Destination php.ini
+  - ps: Add-Content -Path php.ini -Value 'memory_limit=1G'
+  - ps: Add-Content -Path php.ini -Value 'date.timezone="UTC"'
+  - ps: Add-Content -Path php.ini -Value 'extension_dir=ext'
+  - ps: Add-Content -Path php.ini -Value 'extension=php_curl.dll'
+  - ps: Add-Content -Path php.ini -Value 'extension=php_mbstring.dll'
+  - ps: Add-Content -Path php.ini -Value 'extension=php_openssl.dll'
+  - ps: Add-Content -Path php.ini -Value 'extension=php_intl.dll'
+  - ps: Add-Content -Path php.ini -Value 'extension=php_fileinfo.dll'
+  - ps: Add-Content -Path php.ini -Value 'extension=php_gd2.dll'
+  - ps: php --version
+
+  # Prepare composer
+  - ps: If ((Test-Path $Env:composer_directory) -eq $False) { New-Item -Path $Env:composer_directory -ItemType 'directory' }
+  - ps: If ((Test-Path $Env:composer_installer) -eq $False) { appveyor-retry appveyor DownloadFile https://getcomposer.org/installer -FileName $Env:composer_installer }
+  - ps: If ((Test-Path $Env:composer_executable) -eq $False) { php $Env:composer_installer --install-dir=$Env:composer_directory }
+  - ps: Set-Content -Path ($Env:composer_directory + '\composer.bat') -Value ('@php ' + $Env:composer_executable + ' %*')
+
+  # Install dependencies
+  - ps: cd $Env:project_directory
+  - IF %dependencies%==current composer install --no-progress -n
+  - IF %dependencies%==lowest composer update --prefer-lowest --no-progress -n
+  - IF %dependencies%==highest composer update --prefer-dist --no-progress -n
 
 ## Run the actual test
 test_script:
-    - cd c:\projects\php-project-workspace
-    - phpdbg -qrr vendor/phpunit/phpunit/phpunit --coverage-text
+  - ps: cd $Env:project_directory
+  - phpdbg -qrr vendor/phpunit/phpunit/phpunit --coverage-text
diff --git a/composer.json b/composer.json
index 3a9af72..f837d68 100644
--- a/composer.json
+++ b/composer.json
@@ -12,19 +12,19 @@
     "minimum-stability": "dev",
     "prefer-stable": true,
     "require": {
-        "php": "^7.2",
+        "php": "^7.3",
         "ext-json": "*",
-        "amphp/amp": "^2.0",
-        "amphp/artax": "^3.0",
-        "harmonyio/cache": "dev-master"
+        "amphp/amp": "^2.1.1",
+        "amphp/artax": "^3.0.14",
+        "harmonyio/cache": "^1.0.0-rc1"
     },
     "require-dev": {
-        "harmonyio/php-codesniffer-ruleset": "dev-master",
-        "harmonyio/phpunit-extension": "^0.1",
-        "maglnet/composer-require-checker": "^1.1",
-        "phpunit/phpunit": "^7.4",
-        "slevomat/coding-standard": "^4.8",
-        "squizlabs/php_codesniffer": "^3.3.1"
+        "harmonyio/php-codesniffer-ruleset": "^1.0.0-rc1",
+        "harmonyio/phpunit-extension": "^1.0.0-rc1",
+        "maglnet/composer-require-checker": "^1.1.0",
+        "phpunit/phpunit": "^7.5.1",
+        "slevomat/coding-standard": "^4.8.6",
+        "squizlabs/php_codesniffer": "^3.4.0"
     },
     "autoload": {
         "psr-4": {
diff --git a/composer.lock b/composer.lock
index 4f9bab4..d84dfe6 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "1f395b435a2b3dc3b03433b70296bf09",
+    "content-hash": "0cc769953988b658426f276aaa92253b",
     "packages": [
         {
             "name": "amphp/amp",
@@ -144,16 +144,16 @@
         },
         {
             "name": "amphp/byte-stream",
-            "version": "v1.5.0",
+            "version": "v1.5.1",
             "source": {
                 "type": "git",
                 "url": "https://github.com/amphp/byte-stream.git",
-                "reference": "37b9ab16bb8f69c825c3c4e553fe00da73dd6926"
+                "reference": "6bbfcb6f47e92577e739586ba0c87e867be70a23"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/amphp/byte-stream/zipball/37b9ab16bb8f69c825c3c4e553fe00da73dd6926",
-                "reference": "37b9ab16bb8f69c825c3c4e553fe00da73dd6926",
+                "url": "https://api.github.com/repos/amphp/byte-stream/zipball/6bbfcb6f47e92577e739586ba0c87e867be70a23",
+                "reference": "6bbfcb6f47e92577e739586ba0c87e867be70a23",
                 "shasum": ""
             },
             "require": {
@@ -199,7 +199,7 @@
                 "non-blocking",
                 "stream"
             ],
-            "time": "2018-10-22T19:37:37+00:00"
+            "time": "2018-12-27T18:08:06+00:00"
         },
         {
             "name": "amphp/cache",
@@ -862,30 +862,32 @@
         },
         {
             "name": "harmonyio/cache",
-            "version": "dev-master",
+            "version": "v1.0.0-rc1",
             "source": {
                 "type": "git",
                 "url": "https://github.com/HarmonyIO/Cache.git",
-                "reference": "c7a1b1d99f917eac8a35c7556045bb520be92908"
+                "reference": "61ded07e411d7911cc826f3ee756fcb9509b2455"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/HarmonyIO/Cache/zipball/c7a1b1d99f917eac8a35c7556045bb520be92908",
-                "reference": "c7a1b1d99f917eac8a35c7556045bb520be92908",
+                "url": "https://api.github.com/repos/HarmonyIO/Cache/zipball/61ded07e411d7911cc826f3ee756fcb9509b2455",
+                "reference": "61ded07e411d7911cc826f3ee756fcb9509b2455",
                 "shasum": ""
             },
             "require": {
-                "amphp/amp": "^2.0",
+                "amphp/amp": "^2.1.1",
+                "amphp/cache": "^1.2",
                 "amphp/redis": "^0.3.3",
-                "php": "^7.2"
+                "amphp/uri": "^0.1.3",
+                "php": "^7.3"
             },
             "require-dev": {
-                "harmonyio/php-codesniffer-ruleset": "dev-master",
-                "harmonyio/phpunit-extension": "^0.1",
-                "maglnet/composer-require-checker": "^1.1",
-                "phpunit/phpunit": "^7.4",
-                "slevomat/coding-standard": "^4.8",
-                "squizlabs/php_codesniffer": "^3.3.1"
+                "harmonyio/php-codesniffer-ruleset": "^1.0.0-rc1",
+                "harmonyio/phpunit-extension": "^1.0.0-rc1",
+                "maglnet/composer-require-checker": "^1.1.0",
+                "phpunit/phpunit": "^7.5.1",
+                "slevomat/coding-standard": "^4.8.6",
+                "squizlabs/php_codesniffer": "^3.4.0"
             },
             "type": "library",
             "autoload": {
@@ -904,7 +906,7 @@
                 }
             ],
             "description": "Asynchronous caching library",
-            "time": "2018-12-03T09:49:30+00:00"
+            "time": "2018-12-28T00:41:06+00:00"
         },
         {
             "name": "kelunik/certificate",
@@ -1013,21 +1015,21 @@
         },
         {
             "name": "harmonyio/php-codesniffer-ruleset",
-            "version": "dev-master",
+            "version": "v1.0.0-rc1",
             "source": {
                 "type": "git",
                 "url": "https://github.com/HarmonyIO/PHP-CodeSniffer-Ruleset.git",
-                "reference": "d3678daabd50b81e88cacda3053f1e22f61a0f1b"
+                "reference": "ae732ba33cd99d58440d206ca90bbd080809c3a8"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/HarmonyIO/PHP-CodeSniffer-Ruleset/zipball/d3678daabd50b81e88cacda3053f1e22f61a0f1b",
-                "reference": "d3678daabd50b81e88cacda3053f1e22f61a0f1b",
+                "url": "https://api.github.com/repos/HarmonyIO/PHP-CodeSniffer-Ruleset/zipball/ae732ba33cd99d58440d206ca90bbd080809c3a8",
+                "reference": "ae732ba33cd99d58440d206ca90bbd080809c3a8",
                 "shasum": ""
             },
             "require": {
-                "slevomat/coding-standard": "^4.8",
-                "squizlabs/php_codesniffer": "^3.3"
+                "slevomat/coding-standard": "^4.8.6",
+                "squizlabs/php_codesniffer": "^3.4.0"
             },
             "type": "library",
             "notification-url": "https://packagist.org/downloads/",
@@ -1040,33 +1042,33 @@
                     "email": "info@pieterhordijk.com"
                 }
             ],
-            "description": "HarmonyIO coding standard",
-            "time": "2018-11-19T19:25:34+00:00"
+            "description": "HarmonyIO coding standards",
+            "time": "2018-12-24T16:03:36+00:00"
         },
         {
             "name": "harmonyio/phpunit-extension",
-            "version": "v0.1.0",
+            "version": "v1.0.0-rc1",
             "source": {
                 "type": "git",
                 "url": "https://github.com/HarmonyIO/PHPUnit-Extension.git",
-                "reference": "9292b4ae3a100a50b85262fa5c77f2824117fbe5"
+                "reference": "9654c0b2ddd9fb86f00fce77d35d42eabe84d266"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/HarmonyIO/PHPUnit-Extension/zipball/9292b4ae3a100a50b85262fa5c77f2824117fbe5",
-                "reference": "9292b4ae3a100a50b85262fa5c77f2824117fbe5",
+                "url": "https://api.github.com/repos/HarmonyIO/PHPUnit-Extension/zipball/9654c0b2ddd9fb86f00fce77d35d42eabe84d266",
+                "reference": "9654c0b2ddd9fb86f00fce77d35d42eabe84d266",
                 "shasum": ""
             },
             "require": {
-                "amphp/amp": "^2.0",
-                "php": "^7.2"
+                "amphp/amp": "^2.1.1",
+                "php": "^7.3",
+                "phpunit/phpunit": "^7.5.1"
             },
             "require-dev": {
-                "harmonyio/php-codesniffer-ruleset": "dev-master",
-                "phpstan/phpstan": "^0.10.5",
-                "phpunit/phpunit": "^7.4",
-                "slevomat/coding-standard": "^4.8",
-                "squizlabs/php_codesniffer": "^3.3"
+                "harmonyio/php-codesniffer-ruleset": "1.0.0-rc1",
+                "maglnet/composer-require-checker": "^1.1.0",
+                "slevomat/coding-standard": "^4.8.6",
+                "squizlabs/php_codesniffer": "^3.4.0"
             },
             "type": "library",
             "autoload": {
@@ -1085,7 +1087,7 @@
                 }
             ],
             "description": "Asynchronous helpers for PHPUnit",
-            "time": "2018-11-07T02:17:55+00:00"
+            "time": "2018-12-24T18:07:04+00:00"
         },
         {
             "name": "maglnet/composer-require-checker",
@@ -1206,16 +1208,16 @@
         },
         {
             "name": "nikic/php-parser",
-            "version": "v4.1.0",
+            "version": "v4.1.1",
             "source": {
                 "type": "git",
                 "url": "https://github.com/nikic/PHP-Parser.git",
-                "reference": "d0230c5c77a7e3cfa69446febf340978540958c0"
+                "reference": "8aae5b59b83bb4d0dbf07b0a835f2680a658f610"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/nikic/PHP-Parser/zipball/d0230c5c77a7e3cfa69446febf340978540958c0",
-                "reference": "d0230c5c77a7e3cfa69446febf340978540958c0",
+                "url": "https://api.github.com/repos/nikic/PHP-Parser/zipball/8aae5b59b83bb4d0dbf07b0a835f2680a658f610",
+                "reference": "8aae5b59b83bb4d0dbf07b0a835f2680a658f610",
                 "shasum": ""
             },
             "require": {
@@ -1253,7 +1255,7 @@
                 "parser",
                 "php"
             ],
-            "time": "2018-10-10T09:24:14+00:00"
+            "time": "2018-12-26T11:32:39+00:00"
         },
         {
             "name": "phar-io/manifest",
@@ -2563,20 +2565,21 @@
         },
         {
             "name": "symfony/console",
-            "version": "v4.1.7",
+            "version": "v4.2.1",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/console.git",
-                "reference": "432122af37d8cd52fba1b294b11976e0d20df595"
+                "reference": "4dff24e5d01e713818805c1862d2e3f901ee7dd0"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/console/zipball/432122af37d8cd52fba1b294b11976e0d20df595",
-                "reference": "432122af37d8cd52fba1b294b11976e0d20df595",
+                "url": "https://api.github.com/repos/symfony/console/zipball/4dff24e5d01e713818805c1862d2e3f901ee7dd0",
+                "reference": "4dff24e5d01e713818805c1862d2e3f901ee7dd0",
                 "shasum": ""
             },
             "require": {
                 "php": "^7.1.3",
+                "symfony/contracts": "^1.0",
                 "symfony/polyfill-mbstring": "~1.0"
             },
             "conflict": {
@@ -2600,7 +2603,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "4.1-dev"
+                    "dev-master": "4.2-dev"
                 }
             },
             "autoload": {
@@ -2627,7 +2630,133 @@
             ],
             "description": "Symfony Console Component",
             "homepage": "https://symfony.com",
-            "time": "2018-10-31T09:30:44+00:00"
+            "time": "2018-11-27T07:40:44+00:00"
+        },
+        {
+            "name": "symfony/contracts",
+            "version": "v1.0.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/contracts.git",
+                "reference": "1aa7ab2429c3d594dd70689604b5cf7421254cdf"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/contracts/zipball/1aa7ab2429c3d594dd70689604b5cf7421254cdf",
+                "reference": "1aa7ab2429c3d594dd70689604b5cf7421254cdf",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^7.1.3"
+            },
+            "require-dev": {
+                "psr/cache": "^1.0",
+                "psr/container": "^1.0"
+            },
+            "suggest": {
+                "psr/cache": "When using the Cache contracts",
+                "psr/container": "When using the Service contracts",
+                "symfony/cache-contracts-implementation": "",
+                "symfony/service-contracts-implementation": "",
+                "symfony/translation-contracts-implementation": ""
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.0-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Symfony\\Contracts\\": ""
+                },
+                "exclude-from-classmap": [
+                    "**/Tests/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Nicolas Grekas",
+                    "email": "p@tchwork.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "A set of abstractions extracted out of the Symfony components",
+            "homepage": "https://symfony.com",
+            "keywords": [
+                "abstractions",
+                "contracts",
+                "decoupling",
+                "interfaces",
+                "interoperability",
+                "standards"
+            ],
+            "time": "2018-12-05T08:06:11+00:00"
+        },
+        {
+            "name": "symfony/polyfill-ctype",
+            "version": "v1.10.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/polyfill-ctype.git",
+                "reference": "e3d826245268269cd66f8326bd8bc066687b4a19"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/polyfill-ctype/zipball/e3d826245268269cd66f8326bd8bc066687b4a19",
+                "reference": "e3d826245268269cd66f8326bd8bc066687b4a19",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.3.3"
+            },
+            "suggest": {
+                "ext-ctype": "For best performance"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.9-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Symfony\\Polyfill\\Ctype\\": ""
+                },
+                "files": [
+                    "bootstrap.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                },
+                {
+                    "name": "Gert de Pagter",
+                    "email": "BackEndTea@gmail.com"
+                }
+            ],
+            "description": "Symfony polyfill for ctype functions",
+            "homepage": "https://symfony.com",
+            "keywords": [
+                "compatibility",
+                "ctype",
+                "polyfill",
+                "portable"
+            ],
+            "time": "2018-08-06T14:22:27+00:00"
         },
         {
             "name": "symfony/polyfill-mbstring",
@@ -2730,20 +2859,21 @@
         },
         {
             "name": "webmozart/assert",
-            "version": "1.3.0",
+            "version": "1.4.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/webmozart/assert.git",
-                "reference": "0df1908962e7a3071564e857d86874dad1ef204a"
+                "reference": "83e253c8e0be5b0257b881e1827274667c5c17a9"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/webmozart/assert/zipball/0df1908962e7a3071564e857d86874dad1ef204a",
-                "reference": "0df1908962e7a3071564e857d86874dad1ef204a",
+                "url": "https://api.github.com/repos/webmozart/assert/zipball/83e253c8e0be5b0257b881e1827274667c5c17a9",
+                "reference": "83e253c8e0be5b0257b881e1827274667c5c17a9",
                 "shasum": ""
             },
             "require": {
-                "php": "^5.3.3 || ^7.0"
+                "php": "^5.3.3 || ^7.0",
+                "symfony/polyfill-ctype": "^1.8"
             },
             "require-dev": {
                 "phpunit/phpunit": "^4.6",
@@ -2776,7 +2906,7 @@
                 "check",
                 "validate"
             ],
-            "time": "2018-01-29T19:49:41+00:00"
+            "time": "2018-12-25T11:19:39+00:00"
         },
         {
             "name": "webmozart/glob",
@@ -2874,14 +3004,11 @@
     ],
     "aliases": [],
     "minimum-stability": "dev",
-    "stability-flags": {
-        "harmonyio/cache": 20,
-        "harmonyio/php-codesniffer-ruleset": 20
-    },
+    "stability-flags": [],
     "prefer-stable": true,
     "prefer-lowest": false,
     "platform": {
-        "php": "^7.2",
+        "php": "^7.3",
         "ext-json": "*"
     },
     "platform-dev": []
diff --git a/src/Message/CachingRequest.php b/src/Message/CachingRequest.php
index d7e37a3..d904864 100644
--- a/src/Message/CachingRequest.php
+++ b/src/Message/CachingRequest.php
@@ -4,6 +4,7 @@
 
 use HarmonyIO\Cache\CacheableRequest;
 use HarmonyIO\Cache\Key;
+use HarmonyIO\Cache\Ttl;
 
 class CachingRequest extends Request implements CacheableRequest
 {
@@ -12,10 +13,10 @@ class CachingRequest extends Request implements CacheableRequest
     /** @var string */
     private $key;
 
-    /** @var int */
+    /** @var Ttl */
     private $ttl;
 
-    public function __construct(string $key, int $ttl, string $uri, string $method = 'GET')
+    public function __construct(string $key, Ttl $ttl, string $uri, string $method = 'GET')
     {
         $this->key = $key;
         $this->ttl = $ttl;
@@ -28,7 +29,7 @@ public function getCachingKey(): Key
         return new Key(self::CACHE_TYPE, $this->key, md5(serialize($this)));
     }
 
-    public function getTtl(): int
+    public function getTtl(): Ttl
     {
         return $this->ttl;
     }
diff --git a/src/Message/Request.php b/src/Message/Request.php
index 5d2f0c7..2d722f5 100644
--- a/src/Message/Request.php
+++ b/src/Message/Request.php
@@ -32,6 +32,7 @@ public function addHeader(string $key, string $value): Request
 
     /**
      * @param string|RequestBody $body
+     * @throws InvalidBody
      */
     public function setBody($body): Request
     {
diff --git a/src/Message/Response.php b/src/Message/Response.php
index 9a6bbe4..16ff915 100644
--- a/src/Message/Response.php
+++ b/src/Message/Response.php
@@ -93,7 +93,7 @@ public function serialize(): string
      * @param string $serialized
      * @throws InvalidCachedResponse
      */
-    //phpcs:ignore SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingParameterTypeHint
+    // phpcs:ignore SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingParameterTypeHint
     public function unserialize($serialized): void
     {
         $cachedData = json_decode($serialized, true);
diff --git a/tests/Unit/Client/ArtaxClientTest.php b/tests/Unit/Client/ArtaxClientTest.php
index 4fc67e1..4a31b1a 100644
--- a/tests/Unit/Client/ArtaxClientTest.php
+++ b/tests/Unit/Client/ArtaxClientTest.php
@@ -10,6 +10,7 @@
 use Amp\Loop;
 use Amp\Success;
 use HarmonyIO\Cache\Cache;
+use HarmonyIO\Cache\Ttl;
 use HarmonyIO\HttpClient\Client\ArtaxClient;
 use HarmonyIO\HttpClient\Client\Client;
 use HarmonyIO\HttpClient\Message\CachingRequest;
@@ -26,7 +27,7 @@ class ArtaxClientTest extends TestCase
     /** @var MockObject|Cache */
     private $cache;
 
-    //phpcs:ignore SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingReturnTypeHint
+    // phpcs:ignore SlevomatCodingStandard.TypeHints.TypeHintDeclaration.MissingReturnTypeHint
     public function setUp()
     {
         $this->artaxBaseClient = $this->createMock(ArtaxBaseClient::class);
@@ -133,7 +134,7 @@ public function testRequestCachesCachingRequest(): void
         $artaxClient = new ArtaxClient($this->artaxBaseClient, $this->cache);
 
         Loop::run(static function () use ($artaxClient) {
-            yield $artaxClient->request(new CachingRequest('Key', 10, 'https://example.com'));
+            yield $artaxClient->request(new CachingRequest('Key', new Ttl(10), 'https://example.com'));
         });
     }
 
@@ -190,8 +191,8 @@ public function testRequestDoesNotCacheErroringCachingRequest(): void
         $artaxClient = new ArtaxClient($this->artaxBaseClient, $this->cache);
 
         Loop::run(static function () use ($artaxClient) {
-            yield $artaxClient->request(new CachingRequest('Key', 10, 'https://example.com'));
-            yield $artaxClient->request(new CachingRequest('Key', 10, 'https://example.com'));
+            yield $artaxClient->request(new CachingRequest('Key', new Ttl(10), 'https://example.com'));
+            yield $artaxClient->request(new CachingRequest('Key', new Ttl(10), 'https://example.com'));
         });
     }
 
@@ -248,8 +249,8 @@ public function testRequestUsesCacheForConsecutiveCachingRequests(): void
         $artaxClient = new ArtaxClient($this->artaxBaseClient, $this->cache);
 
         Loop::run(static function () use ($artaxClient) {
-            yield $artaxClient->request(new CachingRequest('Key', 10, 'https://example.com'));
-            yield $artaxClient->request(new CachingRequest('Key', 10, 'https://example.com'));
+            yield $artaxClient->request(new CachingRequest('Key', new Ttl(10), 'https://example.com'));
+            yield $artaxClient->request(new CachingRequest('Key', new Ttl(10), 'https://example.com'));
         });
     }
 }
diff --git a/tests/Unit/Message/CachingRequestTest.php b/tests/Unit/Message/CachingRequestTest.php
index 1de2ba9..87e3d63 100644
--- a/tests/Unit/Message/CachingRequestTest.php
+++ b/tests/Unit/Message/CachingRequestTest.php
@@ -4,6 +4,7 @@
 
 use HarmonyIO\Cache\CacheableRequest;
 use HarmonyIO\Cache\Key;
+use HarmonyIO\Cache\Ttl;
 use HarmonyIO\HttpClient\Message\CachingRequest;
 use HarmonyIO\PHPUnitExtension\TestCase;
 
@@ -13,19 +14,22 @@ public function testImplementsCachingInterface(): void
     {
         $this->assertInstanceOf(
             CacheableRequest::class,
-            (new CachingRequest('TestKey', 10, 'https://example.com'))
+            (new CachingRequest('TestKey', new Ttl(10), 'https://example.com'))
         );
     }
 
     public function testGetCachingKey(): void
     {
-        $key = (new CachingRequest('TestKey', 10, 'https://example.com'))->getCachingKey();
+        $key = (new CachingRequest('TestKey', new Ttl(10), 'https://example.com'))->getCachingKey();
 
         $this->assertInstanceOf(Key::class, $key);
     }
 
     public function testGetTtl(): void
     {
-        $this->assertSame(10, (new CachingRequest('TestKey', 10, 'https://example.com'))->getTtl());
+        $this->assertSame(
+            10,
+            (new CachingRequest('TestKey', new Ttl(10), 'https://example.com'))->getTtl()->getTtlInSeconds()
+        );
     }
 }