AWS Lambda and CORS preflight response
Are you struggling with a frontend application that wants to use a backend AWS Lambda API ? Do you have the next CORS problem: Request header field content-type is not allowed by Access-Control-Allow-Headers in preflight response The solution is simple: implement HTTP OPTIONS method respond with the next access control headers : Access-Control-Allow-Origin, Access-Control-Allow-Headers, Access-Control-Allow-Methods For example in python you can do something like this: def return_200(): return { 'statusCode': 200, 'headers': { 'Access-Control-Allow-Origin': '*', 'Access-Control-Allow-Methods': 'GET,HEAD,OPTIONS,POST,PUT', 'Access-Control-Allow-Headers': 'Origin, X-Requested-With, Content-Type, Accept, Authorization', 'Content-Type': 'application/json' }, 'body': json....