使用Postman调用AWS Cognito注册接口遇UnknownOperationException错误排查

Hey there, let's break down why you're hitting that UnknownOperationException when sending your SignUp request via Postman. This error almost always means your request doesn't align with what AWS Cognito's endpoint expects—here are the most likely fixes to check:

1. You're Using the Wrong Request URL #

AWS Cognito User Pools have a dedicated endpoint for SignUp operations. If you're sending your POST to a Cognito Identity endpoint (or any non-User Pool endpoint), AWS won't recognize the SignUp operation.

Your request must be sent to this format:

https://cognito-idp.<your-region>.amazonaws.com/

Replace <your-region> with the region where your User Pool is hosted (e.g., us-east-1, eu-west-1).

2. Typos in the X-Amz-Target Header #

Double-check the exact value of this header—even a tiny typo will break the operation. For SignUp, it needs to be:

AWSCognitoIdentityProviderService.SignUp

Pay attention to casing, spacing, and spelling (no missing letters or extra characters allowed).

3. Invalid Content-Type Header #

AWS requires the exact value application/x-amz-json-1.1 for this header. Using application/json or any variation (with extra spaces, misspellings) will cause AWS to fail parsing your request, leading to this error.

4. Quick Secondary Checks #

While less likely to trigger this specific error, it's worth confirming:

• Your ClientId matches the one generated for your User Pool's app client (check the AWS Console under Cognito > User Pools > Your Pool > App clients).
• The app client has the SignUp operation enabled (it's enabled by default, but worth verifying if you've modified permissions).

内容的提问来源于stack exchange，提问作者Mauricio De armas