I\'m using API Gateway\'s Proxy integration to call a Lambda. The output format specification is this follow JSON format:
{
\"statusCode\": httpStatusCode,
As Mark B pointed out, you can/should achieve this by setting multiple cookie name/value pairs in a single Set-Cookie header. The browser should interpret this correctly.
Cookie: a=1; b=2
Edit: as pointed out by OP, there are use cases that require multiple instances of the header. We've added it our backlog along with supporting multiple header names on incoming requests.