Getting API Usage Plan in header

There is no context variable that contains the usage plan, so you can't directly achieve what you want. If you use a Lambda authorizer, it can calculate the usage plan and return it in a context variable, which later can be used by a mapping template in an HTTP header.

Another option is to include the usage plan name in the API key ID, e.g., plan1-key1, plan2-key3, etc. and use $context.identity.apiKeyId in the mapping template. The backend can then retrieve the information from there.

Thank you Uri for your help. The second suggestion might work. Let me check with my developer.