{
  "grant_type": "authorization_code",
  "code": "auth_code_xyz789",
  "redirect_uri": "https://yourapp.example.com/oauth/callback",
  "client_id": "your_client_id",
  "client_secret": "your_client_secret",
  "code_verifier": "dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk"
}