diff --git a/README.md b/README.md
index 48990d8..3ced4ae 100644
--- a/README.md
+++ b/README.md
@@ -1,11 +1,11 @@
 # Paapi
 
+> **DEPRECATED:** Amazon is shutting down PA-API v5 on May 15, 2026 and replacing it with the [Creators API](https://webservices.amazon.com/paapi5/documentation/). This gem will stop working after that date. Please migrate to the [Vacuum gem (v5.0+)](https://github.com/hakanensari/vacuum), which already supports the new API.
+
 `paapi` is a slim wrapper around [Amazon's Product Advertising API 5.0](https://webservices.amazon.com/paapi5/documentation/).
 
 [![Build Status](https://travis-ci.org/dkam/paapi.svg?branch=master)](https://travis-ci.org/dkam/paapi)
 
-If this gem doesn't meet your needs, try the [Vacuum gem](https://github.com/hakanensari/vacuum).
-
 ## Installation
 
 Add this line to your application's Gemfile:
diff --git a/lib/paapi.rb b/lib/paapi.rb
index e87eb4f..261b314 100644
--- a/lib/paapi.rb
+++ b/lib/paapi.rb
@@ -6,6 +6,13 @@ require "paapi/listing"
 require "paapi/response"
 
 module Paapi
+  DEPRECATION_MESSAGE = <<~MSG.freeze
+    [DEPRECATION] The paapi gem is deprecated and will stop working after May 15, 2026.
+    Amazon is replacing PA-API v5 with the Creators API.
+    Please switch to the vacuum gem (v5.0+): https://github.com/hakanensari/vacuum
+  MSG
+
+  warn DEPRECATION_MESSAGE
   class Error < StandardError; end
 
   class NotImplemented < StandardError; end