diff --git a/README.md b/README.md
index fcbe52b..e82847c 100644
--- a/README.md
+++ b/README.md
@@ -175,7 +175,10 @@ account or login locally:
 
 By the end of this section, you should be able to search Amazon products and
 add items to wishlists on your local machine (when your logged-in user is an
-admin or site manager).
+admin or site manager). *Note: if you're adding a new API endpoint, read more
+[here][API client README].*
+
+[API client README]: lib/amazon_product_api/README.md
 
 **This step is only required for site managers and admins searching/adding
 Amazon products.** If your issue doesn't involve working with the Amazon
diff --git a/lib/amazon_product_api/README.md b/lib/amazon_product_api/README.md
new file mode 100644
index 0000000..1fa9cc8
--- /dev/null
+++ b/lib/amazon_product_api/README.md
@@ -0,0 +1,68 @@
+# Amazon Product Advertising API Client
+
+This folder contains the wrapper code for the Amazon Product Advertising API.
+For more details on the API, check the [Amazon documentation].
+
+[Amazon documentation]: http://docs.aws.amazon.com/AWSECommerceService/latest/DG/Welcome.html
+
+## Adding an Endpoint
+
+All endpoints should be subclassed from `AmazonProductAPI::Endpoint`. In order
+to add a new endpoint, you'll need to modify the template below in a few ways:
+
+  * Prepend any new attributes to the `#initialize` parameter list. Any
+    validations or processing can be done in `#initialize` as shown. Note:
+    setting `aws_credentials` is **required**!
+
+  * Add endpoint-specific request parameters to `#request_params`. These can
+    be found in the Amazon API documentation.
+
+  * Add any post-processing of the API response in `#process_response`.
+
+  * Update the class name and comments.
+
+### Endpoint Template
+
+```ruby
+require 'amazon_product_api/endpoint'
+
+module AmazonProductAPI
+  # Responsible for building and executing <...>
+  #
+  # <endpoint url>
+  #
+  # Contains all specialization logic for this endpoint including request
+  # parameters, parameter validation, and response parsing.
+  class TemplateEndpoint < Endpoint
+    # Add any parameters you need for the specific endpoint.
+    #
+    # Make sure you set `@aws_credentials`-the query won't work without it!
+    def initialize(aws_credentials)
+      # Attribute validations
+      # raise InvalidQueryError, 'reason' if ...
+
+      # Initialize attributes
+      @aws_credentials = aws_credentials
+    end
+
+    private
+
+    attr_accessor :aws_credentials # any other attrs
+
+    # Add any post-processing of the response hash.
+    def process_response(response_hash)
+      ExampleResponse.new(response_hash).item
+    end
+
+    # Include request parameters unique to this endpoint.
+    def request_params
+      {
+        # 'Operation' => 'ItemLookup',
+        # 'IdType' => 'ASIN',
+        # 'ItemId' => 'the item asin',
+        # ...
+      }
+    end
+  end
+end
+```