Limitations of Bot API in Comparison to Telegram API
This table, kindly provided by @vanutp, shows how Bot API and Telegram API differ in terms of developing bots.
| Feature | Bot API | Telegram API | Read more |
|---|---|---|---|
| Fetch messages | From updates only | From updates or by message IDs | Updates |
| Fetch users | From updates only | - From updates - By message IDs (if the bot "saw" the user) - By username (200 times a day) | Seen users |
| Send and receive files | ↓ 20 MB, ↑ 50 MB (without a local server) | Like regular users | Bot API docs: Local server |
| Fetch group members | No | Yes | |
| Get old updates | No | Yes | |
| Run multiple programs with the same bot | Only if other programs use Telegram API | Yes | Receiving updates multiple times |
See the pages on what is Bot API and Telegram API and API libraries,