Compress PDFs in Telegram: the PDFThin bot beta
A 21 MB PDF is too large for the bot’s current 20 MB input limit. Use the website for larger files. For a smaller PDF, follow the steps below and wait for the result before starting another request.
Can I send a 21 MB PDF?
No. The public beta currently accepts files up to 20 MB and one PDF per minute per user. You can have one unfinished processing request at a time. For a 21 MB PDF, use the website compressor.
The cloud Telegram Bot API limits the files a bot can download to 20 MB. Splitting or compressing a file elsewhere may help, but check every resulting file against the limit before sending it. Beta limits may change; /start shows the current settings.
Start the bot and send the file
Open @pdfthin_bot and send /start. Attach the PDF as a file, not a photo or screenshot. The bot supports English, German, French, Spanish, Italian, Portuguese and Swedish.
After the bot confirms receipt, tap “Compress all” below the message or send /process. The button keeps its English label in every language. Commands and buttons do not use your PDF quota. If you send another PDF too soon, follow the bot’s message telling you how many seconds to wait.
Wait for queue confirmation
Wait for the message confirming that the request is in the shared queue. The wait depends on demand; the file-received message alone does not mean processing has started.
If the queue is full or you already have an unfinished request, the bot reports that the new request was not added. Let the current request finish or try again later. Avoid sending repeated copies while you are waiting.
Check the result or error
After processing, the bot sends the result to the same chat with a short outcome message. A processing failure or an expired wait produces an error. If confirmation or delivery is uncertain, check the chat before retrying. Waiting time depends on demand.
On 13 October 2026, we sent our own generated one-page scan of 1,210,534 bytes. The bot returned a file of the same size. The sender confirmed receipt, and the saved result was byte-identical to the source. The file already fitted the target; a smaller result is not guaranteed.
Test settings: Gmail 25 MB preset, default quality, smart mode off; PDFThin build 3a103e3. Keep the original and check your result before forwarding it.
Privacy
During the beta, use PDFs that are not confidential. Files processed on our servers are deleted automatically after 60 hours. This does not delete the messages or files in your Telegram chat; you manage those in Telegram.
The privacy policy explains file retention and the bot’s usage statistics. These replace your Telegram ID with a pseudonym and do not include PDF contents or file names.