Telegram Bot API: Localization, Testing, and Local Bot API

Purpose

Use this skill when hardening a bot for real deployment.

Language support guidance

• Use language_code from updates when available.
• Provide fallback behavior when it is absent.
• Localize:
  • text responses
  • command descriptions
  • bot name/description/about text where needed
  • inline results and Mini App UI

Testing guidance

• Keep a separate test bot token for safe experimentation.
• Replay real update payloads as fixtures.
• Add contract tests for:
  • formatting
  • callback data parsing
  • topic-aware routing
  • permission-dependent features
  • payment and business flows

Webhook troubleshooting

• Check getWebhookInfo.
• Watch pending_update_count.
• Inspect last_error_message.
• Verify HTTPS, supported ports, certificate validity, and secret token checks.

Local Bot API server

• Use it when you need:
  • larger file handling
  • local-path upload support
  • local webhook/network flexibility
• Follow Telegram's guidance for logOut and close when moving between cloud and local servers.

Operations guidance

• Handle retry_after.
• Instrument update latency and handler failures.
• Use queueing/backoff for broadcasts and slow tasks.
• Watch for BotFather status alerts on degraded responsiveness.

Common mistakes

• Testing production flows with the live bot token.
• Assuming every user has language_code.
• Switching to the local Bot API without following migration steps.
• Ignoring webhook diagnostic fields during incidents.

Read next

• 02-getting-updates
• 11-payments-stars-and-broadcasting
• 21-schema-and-type-modeling