How Telegram authorization works

What is Telegram login

Telegram authorization is a way to quickly confirm your identity on a website or app using your telegram account. Instead of registering from scratch, you allow Telegram to transfer basic profile data (ID, name, nickname, avatar) with a cryptographic signature to the site, and the site creates/binds an account and starts a session.

Key advantages:

Speed: 1-2 taps - without password and e-mail confirmations.
Reliability: data comes signed by Telegram; the site can check them.
Unification: the same telegram account works on the web, mobile web and inside Telegram WebApp.

Telegram authorization options

1. Telegram Login Widget (websites).

The page displays the official button. After clicking Telegram, it shows a confirmation window, then returns to the site a set of fields + signature (hash), which the server checks and creates a session.

2. Authorization via bot (login URL/deep-link).

The user opens the bot using a special link (login_url). The bot receives confirmation from Telegram and sends the site user data with a signature.

3. Telegram WebApp (inside the chat/bot).

The site opens in the "built-in browser" Telegram (WebApp). The client passes an initData object to WebApp with user parameters and a crypto signature, according to which the backend validates requests.

💡 All three scenarios are built around one principle: the site does not trust the browser, but Telegram signatures, checking it on the server before issuing a session.

What the user sees (step by step)

1. Clicks "Log in via Telegram" (on the site/in the bot/in WebApp).

2. Telegram shows a confirmation window (or uses an already confirmed session in the client).

3. After consent, the site automatically receives your telegram_id, name, nickname (if any), avatar (URL) and authorization time stamp.

4. The site creates or links an account and logs you in - most often without entering a password.

What happens on the server (brief and clear)

1. The site receives a set of parameters from the client (for example: 'id', 'first _ name', 'username', 'photo _ url', 'auth _ date', 'hash').

2. The server generates a data-check-string: sorts the 'key = value' pairs alphabetically, excluding 'hash', and joins with a line feed character.

3. The server calculates the HMAC-SHA256 from this string with a secret derived from the bot token (the secret is the SHA256 from the bot token).

4. Compares the result with the incoming 'hash'. If'auth _ date'matches "fresh" (usually a validity window ≤ 24 hours), the data is considered genuine.

5. The server is looking for a user by 'telegram _ id'.

If found, authorizes and updates the profile.

If not, creates a new account and login.

6. Gives a session token/cookie to a site or application token.

💡 Meaning: even if someone tries to change a name or nickname, the signature will break and the server will reject the login.

What exactly is transmitted to the site

Required: 'id' (telegram_id), 'auth _ date', 'hash'.

Often: 'first _ name', 'last _ name', 'username', 'photo _ url', sometimes the interface language.

No access to correspondence, contacts, etc. - this is not OAuth social networks, where broad permissions are requested.

How to link Telegram to a casino account (for the player)

1. Go to the profile on the site/in the application.

2. Click "Link Telegram "/" Log in via Telegram."

3. Confirm the request in Telegram.

4. Done: your account has contacted your 'telegram _ id'. Now you can use:

quick login through the button, notifications about transactions/tournaments in the bot, WebApp interface (cash desk/leaderboards) directly to Telegram, if provided.

Security and Compliance

Signature verification - server only. Client checks are unreliable.

Validity window. Check'auth _ date '(for example, ≤ 86400 seconds).

A bunch of devices. For critical actions (output, change of details), require 2FA/password, even if the login was via Telegram.

CSRF/Replay protection. Use nonce/' state 'in redirects, bind the session to the device/browser.

Domain restriction. Login button and WebApp should only work on trusted domains.

Data storage. Minimize: 'telegram _ id' as primary communication key; do not cache extra fields. Comply with local data laws (GDPR and equivalent).

Uncoupling. Give the user the "Disable Telegram" button and delete the bundle correctly.

Antifraud. Log in to the IP/device with a login, apply risk scoring, limits on attempts.

Responsible play. Even with a convenient login, follow KYC/AML and account limits.

Telegram WebApp: what is different

Launch inside Telegram with the transfer of'initData' (parameter package + signature).

Accompany all requests to your API with a header/parameter with initData and validate the signature on the server according to the same principle (HMAC-SHA256 with a secret from the bot token).

Advantages: native buttons, sharing, quick scripts (wallet, tournaments, tasks) without switching to the browser.

Restrictions: depends on the Telegram client (built-in WebView), platform policies and browser API capabilities.

Typical Use Cases

Fast onboarding. A new player enters via Telegram, the site creates an account and immediately offers to set limits/2FA.

Single sign-on for Web and WebApp. The user began in the chat, continued in the browser - progress and wallets are common.

Alerts in the bot. Deposits, withdrawal statuses, tournament pin codes.

Referral links. Through deep-link 'start', you can pass the ref code and bind the source at the first login.

Common Issues and Solutions

"Invalid signature/hash mismatch." Check:

the line for the signature was collected in alphabetical order, the'hash' was excluded from the line, the secret = SHA256 from the bot token, and not the token itself, use HMAC-SHA256, not just SHA256.
"Expired auth_date". Enlarge the window (but moderately) and consider possible clock drift.
"The login passes at the front, and falls on the server." Validation shall be server-based; do not trust the result of the front.
"The user has lost access to Telegram." Give an alternative: login by e-mail/password + 2FA, untethering procedure through support.
"Duplicate accounts." At the first login, try to find the user by e-mail/phone and suggest a merger with confirmation.

Best practices (for players)

Link Telegram to an already created account so as not to lose history and bonuses.

Leave 2FA enabled in your account (telegram input is not a replacement for the second factor).

Do not report codes/links to "managers" in your personal account - do any operations only through the official bot/button on the site.

If you lose access to Telegram, know in advance the procedure for restoring login on the site.

Best Practices (for product/development)

Server-side signature validation, time window, anti-replay.

Limits on the frequency of logins, audits, anomaly alerts.

Transparent binding/unlinking of Telegram, export/deletion of data on request.

Granular policies: "login via Telegram is allowed, but output is only with re-authentication."

Test Login Widget/WebApp in different Telegram clients and browsers.

FAQ

Is this OAuth?

It looks like UX, but technically simpler: Telegram transmits a signed data packet, and does not issue tokens for access to user resources.

Can I log in without a Telegram application?

If you use Login Widget on the web, Telegram will still confirm you through its client/web layer. The installed client speeds up the process.

Is contact/chat history shared?

No, it isn't. The site receives only the basic fields of the + 'telegram _ id' profile, and all this with a signature.

Is it safe?

With proper server signature verification and time window limitation, yes. Optionally include 2FA and critical action limits.

Telegram authorization is a fast and secure way to log in with Telegram signed data. The user gets instant access without a password, the product - reliable identification without storing unnecessary personal data. It is only important to strictly validate the signature on the server, limit the time window and combine telegram login with 2FA and responsible security policies.