How to Check if a Number Is on Telegram (Checker API)

Published August 23, 2026

Telegram has over a billion users, and in many regions and communities it’s the primary messaging channel — which makes “is this contact on Telegram?” a question worth answering before you build outreach, support, or verification flows around it. A Telegram number checker answers it with a single API call.

This guide shows how to check whether a number (or username) is registered on Telegram, and how to fetch the public bio and avatar for registered accounts.

Step 1 — Get an API key

Sign up, open your Dashboard, and copy an active API key. Free credits are included for testing.

Step 2 — Check registration

The check-exists operation takes a peer, which can be a phone number in international format (digits only) or a Telegram username:

curl "https://api.opendata-api.com/api/project/telegram/check-exists?key=YOUR_API_KEY&peer=15551234567"

Being able to pass a username is especially useful when you only have someone’s Telegram handle rather than their phone number.

For registered peers, the check returns an identifier (userHash) used by the profile operations.

Step 3 — Fetch bio and avatar

Pass the userHash from the check to the profile endpoints:

# Bio / "about" text
curl "https://api.opendata-api.com/api/project/telegram/get-about?key=YOUR_API_KEY&userHash=USER_HASH"

# Profile photo
curl "https://api.opendata-api.com/api/project/telegram/get-picture?key=YOUR_API_KEY&userHash=USER_HASH"

Keeping the cheap existence check separate from profile lookups means you only spend enrichment credits on peers that actually exist.

Use cases

  • Channel routing — send to Telegram only for contacts confirmed to be there.
  • Community & lead research — enrich Telegram handles with bio and avatar data.
  • Verification flows — confirm a user controls a reachable Telegram account.
  • List cleaning — drop non-Telegram contacts from Telegram-specific campaigns.

Best practices

  • Accept both numbers and usernames — don’t force a phone number when a handle is all you have.
  • Validate before enriching — skip bio/avatar calls for peers that fail the check.
  • Cache userHash so repeat lookups don’t cost extra.
  • Respect the platform and privacy law — only process contacts you have a legitimate basis to use.

Try it

Test the checker on the Telegram Number Validation page, or read the check-exists reference. See pricing when you’re ready to go beyond the free credits.