title: AWS API Gateway: Error 429 Too many requests
body: <p>I'm trying to create a <strong>backend</strong> system with <strong>AWS API Gateway</strong> and <strong>Lambda</strong>.<br>
  In the past days I created a PUT method for a new API resource, with an API Key as a simple first security step. The PUT method invoke a Lambda function on AWS.<br>
  Then I deployed this API to a "prod" stage for some tests. </p>
  
  <p><strong>In the first days everything were working well as expected</strong>: I created a call to the API with postman and I received all the data I was expecting.
  But a couple of days ago I started to receive <strong>always</strong> the <strong>429</strong> <em>"Too many requests"</em> response. I created also a new stage, but nothing changed: also the new stage, with the same version or with newer version, is getting always the same error.<br>
  The API is not reaching any limit, because they are called 4 or 5 times per <strong>day</strong>, not per second (checked on CloudWatch). There is no cycle, it is only a single invocation. 
  I suppose there is no error on the lambda side, because if I test the API in the AWS API Gateway console I get no error (and the lambda was working well in the past, no new changes from that version). The error only shows when I use an external client to test my api (in my case it is Postman).</p>
  
  <p>Can anyone help to solve this problem?</p>
  
  <p>UPDATE: I've just created a POST method on the same resource, with the same parameters and the same lambda. It is working. I wonder if the problem is related to the <strong>PUT</strong> methods in general or if within 2 days also my <strong>POST</strong> method will be affected by the same problem.</p>