diff --git a/Makefile b/Makefile
index 758dad6..5e974b3 100644
--- a/Makefile
+++ b/Makefile
@@ -1,8 +1,8 @@
 
 # Use this tag to build a customized local image
 
-SWIFT_VERSION=5.1
-LAYER_VERSION=5-1
+SWIFT_VERSION?=5.1
+LAYER_VERSION?=5-1
 # SWIFT_VERSION=5.0.3
 # LAYER_VERSION=5-0-3
 DOCKER_TAG=nio-swift:$(SWIFT_VERSION)
@@ -13,10 +13,10 @@ SWIFT_CONFIGURATION=release
 # Configuration
 
 # HelloWorld Example Configuration
-SWIFT_EXECUTABLE=HelloWorld
-SWIFT_PROJECT_PATH=Examples/HelloWorld
-LAMBDA_FUNCTION_NAME=HelloWorld
-LAMBDA_HANDLER=$(SWIFT_EXECUTABLE).helloWorld
+SWIFT_EXECUTABLE?=HelloWorld
+SWIFT_PROJECT_PATH?=Examples/HelloWorld
+LAMBDA_FUNCTION_NAME?=HelloWorld
+LAMBDA_HANDLER?=$(SWIFT_EXECUTABLE).helloWorld
 
 # HTTPSRequest Example Configuration
 # SWIFT_EXECUTABLE=HTTPSRequest
@@ -46,8 +46,8 @@ DOCKER_PROJECT_PATH=aws-lambda-swift-sprinter/$(SWIFT_PROJECT_PATH)
 # DOCKER_PROJECT_PATH=$(SWIFT_PROJECT_PATH)
 
 # AWS Configuration
-AWS_PROFILE=default
-AWS_BUCKET=my-s3-bucket
+AWS_PROFILE?=default
+AWS_BUCKET?=my-s3-bucket
 
 swift_test:
 	docker run \
diff --git a/README.md b/README.md
index 8b03274..b9c7fb5 100644
--- a/README.md
+++ b/README.md
@@ -140,16 +140,54 @@ make package_lambda
 ```
 The output of this command is a ZIP file called `lambda.zip` under the folder `.build`.
 
-**Note:**
+# Lambda Configuration
 
-Edit the `Makefile` to build a different Example by commenting the following lines and uncommenting the line relateted to the example you want to build.
+## Parametrized calls / Automation
+
+Can pass values to your `make` command either before or after the call like below. This will fit better in a script per example to setup continuous integration in your project.
+
+### Before `make`
+
+```
+SWIFT_EXECUTABLE=HTTPSRequest \
+SWIFT_PROJECT_PATH=Examples/HTTPSRequest \
+LAMBDA_FUNCTION_NAME=HTTPSRequest \
+LAMBDA_HANDLER=${SWIFT_EXECUTABLE}.getHttps \
+    make invoke_lambda
+```
+
+### After `make`
+
+```
+make invoke_lambda \
+    SWIFT_EXECUTABLE=HTTPSRequest \
+    SWIFT_PROJECT_PATH=Examples/HTTPSRequest \
+    LAMBDA_FUNCTION_NAME=HTTPSRequest \
+    LAMBDA_HANDLER=HTTPSRequest.getHttps
+```
+
+### Parameters you can pass
+
+| Key | Usage | Default |
+| --- | --- | --- |
+| AWS_PROFILE | An AWS AIM profile you create to authenticate to your account. | default |
+| SWIFT_VERSION | Version of Swift used / Matches Dockerfile location too from `docker/` folder. | 5.1 |
+| LAYER_VERSION | Version of the Swift layer that will be created and uploaded for the Lambda to run on. | 5-1 |
+| SWIFT_EXECUTABLE | Name of the binary file. | HelloWorld |
+| SWIFT_PROJECT_PATH | Path to your Swift project. | Examples/HelloWorld |
+| LAMBDA_FUNCTION_NAME | Display name of your Lambda in AWS. | HelloWorld |
+| LAMBDA_HANDLER | Name of your lambda handler function. If you declare it using `sprinter.register(handler: "FUNCTION_NAME", lambda: syncLambda)` you should declare it as `<SWIFT_EXECUTABLE>.<FUNCTION_NAME>`. | $(SWIFT_EXECUTABLE).helloWorld |
+
+## Manual change
+
+You can also edit the `Makefile` to build a different Example by commenting the following lines and uncommenting the line relateted to the example you want to build.
 ```
 ...
 
-SWIFT_EXECUTABLE=HelloWorld
-SWIFT_PROJECT_PATH=Examples/HelloWorld
-LAMBDA_FUNCTION_NAME=HelloWorld
-LAMBDA_HANDLER=$(SWIFT_EXECUTABLE).helloWorld
+SWIFT_EXECUTABLE?=HelloWorld
+SWIFT_PROJECT_PATH?=Examples/HelloWorld
+LAMBDA_FUNCTION_NAME?=HelloWorld
+LAMBDA_HANDLER?=$(SWIFT_EXECUTABLE).helloWorld
 
 ...
 ```