Apple receipt Firebase validator function

This is a simple function to verify an iOS app receipt using Apple servers. It uses bent, a very small functional HTTPS client with zero dependencies and can be deployed with the standard firebase deploy command.

Testing

To test, just make a POST request to your function with a base64 encoded receipt in the body.

Using Postman

Postman is a free API client for developers. Create a POST request, put your base64 encoded receipt—without quotes—in the Body as raw Text. Check if Content-Type is set to text/plain in the Header, send it and check the response.

A sample receipt, still working as of June 2020, can be found on this Stackoverflow post.

Apple response status codes

[0]:     { message: 'Active', valid: true, error: false },
[21000]: { message: 'App store could not read', valid: false, error: true },
[21002]: { message: 'Data was malformed', valid: false, error: true },
[21003]: { message: 'Receipt not authenticated', valid: false, error: true },
[21004]: { message: 'Shared secret does not match', valid: false, error: true },
[21005]: { message: 'Receipt server unavailable', valid: false, error: true },
[21006]: { message: 'Receipt valid but sub expired', valid: true, error: false },
[21007]: { message: 'Sandbox receipt sent to Production environment', valid: false, error: true, redirect: true },
[21008]: { message: 'Production receipt sent to Sandbox environment', valid: false, error: true },

Some online docs

• Firebase TypeScript functions
• Apple receipts