The API exists. It just isn't public.

To find an undocumented API we look at what the app can do, then trace how each feature reaches the server. The private endpoint is the path behind the feature that has no public equivalent.

syntax = "proto3";

message LookupRequest {
  string id = 1;
  string locale = 2;
  bytes device_token = 3;
  int64 nonce = 4;
}

Fig. 02 · the field numbers and types the server actually reads

A private endpoint is usually reachable once the app can prove a session. We reconstruct the auth flow: how the app gets a token, where it stores it, what it sends back, and whether each request is signed or derived from a device value.

This is the last step of reverse engineering an undocumented API: take the endpoint, the shape and the auth, and return a client that reproduces them so you can use the Android app API without the app itself.

import grpc, time, secrets
import messages_pb2 # our reconstructed module

def lookup(identifier, token):
    req = messages_pb2.LookupRequest(
        id=identifier, locale="en",
        device_token=derive_device_token(token),
        nonce=int(time.time() * 1000))
    return stub.Lookup(req, metadata=(
        ("authorization", bearer(token)),
        ("x-nonce", req.nonce),))

Fig. 03 · endpoint, shape and auth reproduced as a working call