How the casino integrates Telegram WebApp

Why Telegram WebApp casino

Low friction: entry into 1-2 taps from the dialogue with the bot, without "site search."

Instant delivery features: frontend lives on your domain, releases via CDN.

Linking to a Telegram profile: an understandable user identifier and ready-made communication channels (bot messages instead of fluffs).

Marketing-reach: links' t. me/... 'and buttons in channels/chats.

💡 Important: Telegram has its own rules for payments and content. For gambling, observe jurisdictions, geo locks and site conditions. It is better to display some of the payment scenarios in an external browser (see the section "Cash and restrictions").

Architecture: what integration consists of

Components:

1. Bot API layer (webhook/long-polling): accepts commands, sends a menu, launches WebApp.

2. WebApp (SPA/PWA) on your domain: lobby, profile, promo, light game scenes, cash router.

3. Casino platform API: authentication, balance/bets, bonuses, box office, stories.

4. Session/linking storage: link 'telegram _ user _ id ↔ account_id'.

5. CDN + anti-bot/fraud: protection and distribution of mini-application assets.

Startup thread:

The user writes to the bot → presses the "Open" button (web_app).
Telegram embeds your WebApp into the client and sends you'initData '(signed user/chat parameters).
WebApp checks the signature on the backend → creates/resumes a session in the casino → gives the UI.

Launching WebApp: buttons and deep-link

Options:

Кнопка в ReplyKeyboard/InlineKeyboard c `web_app: {url: "https://your. app/tg"}' - opens the widget inside Telegram.
Main Menu (BotFather → Menu Button) - permanent button "Open."
Deep-link `https://t. me/< bot>? startapp = '- throw the starting context (for example, promo/referral/game).

Tip: Use 'startapp' to securely communicate 'intent' (which screen to open). Determine the content itself and rights after checking the signature.

Account authentication and linking

What comes to WebApp

The Telegram client adds a Telegram JS object to the window. WebApp 'and the string' initData '/' initDataUnsafe '- user/chat information, time and signature.

To confirm a user

1. At the front, take 'Telegram. WebApp. initData 'and send it as is to your backend.

2. On the backend, check the signature using the Telegram algorithm (HMAC-SHA256 on the data line with a key derived from the bot token; exact algorithm - in the official Telegram documentation).

3. If the check is successful, extract the'user. id ',' username 'and metadata → find or create the' telegram _ user _ id ↔ account_id' link.

4. Give the front a short-lived JWT/session token of the casino platform (for example, TTL 10-30 min + refresh using a secure API).

💡 Never trust'initData 'without verifying the signature on the server. Do not use "user_id from the front" as the only source of truth.

Bot data exchange ↔ WebApp

From WebApp to bot: 'Telegram. WebApp. sendData(JSON. stringify (payload)) '- the bot will receive' web _ app _ data 'and can respond with a message/button.

UI events inside WebApp: 'MainButton', 'BackButton', 'HapticFeedback', 'onEvent (' themeChanged'	'viewportChanged'	…)`.
Closing the mini-application: 'Telegram. WebApp. close () '- convenient after "successfully completed."

Pattern: complex operations (cash register, verification) are conducted in WebApp; bot - for triggers/notifications ("bonus activated," "KYC approved").

Cash register and platform limitations

Telegram payments: the platform has built-in payment mechanics and separate rules by category. For gambling, apply local laws and Telegram policies.

Practical approach:

Open a check-out in an external browser (deeplink 'target = _ blank') with a full KYC/AML/KYT loop and idempotency keys.
For replenishment/inference, show only the methods allowed for the user's country (geo-fencing).
Always duplicate confirmations in bot chat (as a replacement for pooches).

UX: How to do it "natively" and quickly

Theme/Colors: Use'Telegram. WebApp. themeParams' and'colorScheme' (light/dark), change in runtime by'themeChanged'.

Navigation: 'MainButton. setText ('Continue'). show()`; `BackButton. show () 'and the' onEvent ('backButtonClicked',...) 'handler.

Viewport: `Telegram. WebApp. expand()`; follow 'viewportHeight' (especially on iOS).

Localization - Take the language from'initDataUnsafe. user. language_code' + your i18n.

Performance: PWA + Service Worker, CDN with hash assets, lazy-chunks. Initial screen ≤ 150-200 KB br.

Micro-example (front):

html
<script>
const tg = window. Telegram. WebApp;
tg. expand();
tg. MainButton. setText ('Open Lobby'). show(). onClick(() => {
//send a signal to the bot (optional), or just routim inside the SPA tg. HapticFeedback. impactOccurred('medium');
});
//send initData to the server to verify fetch ('/api/tg/auth ', {method:' POST ', headers: {' Content-Type ':' application/json '}, body: JSON. stringify({ initData: tg. initData })});
</script>

Security: mandatory measures

Verifying'initData 'signature on server. Keep "fresh window" (e.g. 1-5 min) - discard old signatures.

Bundle of identities: 'telegram _ user _ id' is a profile attribute, but access to money is always through your token/session.

Bot webhooks: secret path ('/bot 'or its own header), Telegram IP-allowlist, timeouts/idempotency.

Anti-bot: device-fingerprint and behavioral signals in WebApp, rate-limit by 'telegram _ user _ id' and IP.

Content security: CSP for mini-app domain, 'X-Frame-Options' does not interfere with embedding in Telegram, strict CORS to API.

Logs and PII: disguise, store according to GDPR/local regulations, use WORM for payment/gaming events.

Telemetry and Analytics

RUM: TTFB/LCP/TTI inside WebApp; события «open_from_deeplink», «auth_ok», «deposit_start/success», «bet_place».

Channel tags: check the referral/utm through 'startapp' → associate with a casino session.

SLO: p95 'auth _ via _ initData' ≤ 200-300 ms, p95 "initial screen" ≤ 2 s, signature verification error <0. 1%.

Fraud signals: anomalies by country/hour/device, mass discoveries without action, repeated 'startapp'.

Typical backend (pseudocode)

pseudo
POST /api/tg/auth { initData }
assert verifyTelegramSignature (initData )//strictly at the docks Telegram let tgUser = parse (initData)
let account = findOrCreateByTelegram(tgUser. id)
let session = issueJWT(account_id, ttl=20m, scope='webapp')
return { token: session. jwt, account }

POST /api/cashier/deposit { token, method, amount }
assert auth(token)
assert geoAllowed(account. country)
createIdempotencyKey()
redirectToPSP (... )//to external browser

POST /api/bot/webhook verifyTelegramSignatureOrSecret()
handle commands, web_app_data, callbacks reply with messages/buttons

Telegram WebApp launch checklist for casino

Law and politics

Jurisdictions, geo-blocking, RG/KYC texts in locales.
Telegram policy for your category, whitelists of countries/channels.

Authentication

Server verification of the signature'initData' (including the freshness window).
Linkovka 'telegram _ user _ id ↔ account_id', short JWT.

Cash desk

Check-out output to external browser (where necessary), idempotency, KYC/KYT.
Geo-dependent methods, duplicate status bots.

Frontend

Theme/colors from 'themeParams', 'MainButton/BackButton', 'expand ()'.
PWA/SW, CDN with hash assets, LCP ≤ 2 s.

Safety

Webhooks: secret/allowlist/timeouts.
Rate-limits, anti-bot, CSP/CORS.
WORM logs for money/games; PII masking.

Analytics

RUM metrics, onboarding/checkout/betting events.
Channel attribution via'startapp '.

Anti-patterns

Trust'initData 'at the front without server verification.

Try to "squeeze" a full check-out into WebApp, ignoring politics/jurisdictions.

Hardcode theme/colors → unreadable in dark/light Telegram theme.

Lack of idempotency at the checkout and bot webhooks.

Long-lived sessions without rotation or recall.

A monolithic bundle of 5-10 MB → a slow first screen and a dump of the session.

Telegram WebApp integration gives the casino fast login, convenient communication and a lightweight client without installation. Success - in correct authentication through 'initData', accurate linking of the account and compliance with payment/content policies. Add native UX (theme, buttons, haptics), CDN delivery of assets, strong security and measurable analytics - and the mini-application will become an effective acquisition and retention channel that scales without pain.