gRPC-Web Developer Tools od SafetyCulture

gRPC-Web Developer Tools for debugging application's gRPC-Web network requests.
gRPC-Web Developer Tools is a Firefox DevTools extension for the official gRPC-Web library. It allows you to inspect the gRPC network log in the Firefox Developer Tools, and displayed as the deserialized JSON objects, rather than the base64 encoded binary format.

You will get a new tab called gRPC-Web in your Firefox DevTools. This will start recording gRPC client network requests that have been configured (see Usage for details). Features are similar to the default Network tab, but only tracks gRPC requests.

Selecting a network log entry will display the deserialized JSON for the request, response and any error object returned by your gRPC server.