@dmaximyuk/signature

Library for working with Telegram and VKontakte signatures: encode raw init/launch data into a compact string and verify signatures on the backend. Compatible with Bun.js, Node.js, and the browser.

Installation

npm install @dmaximyuk/signature
# or
bun add @dmaximyuk/signature

Usage

Telegram

Frontend (or any source): turn raw initData (query string) into a compact string to send to the backend.

import { telegramEncode, telegramDecode, type TelegramDecodeResult } from '@dmaximyuk/signature';

const rawInitData = new URLSearchParams(window.Telegram?.WebApp?.initData || '').toString();
const encoded = telegramEncode(rawInitData);

Backend: verify signature and extract user data.

const validator = telegramDecode({ token: process.env.TG_BOT_TOKEN });
const result = validator(encoded);
if (result) {
  console.log(result.userId, result.user);
}

VKontakte

Frontend: turn raw launch params (query string with sign) into a compact string.

import { vkontakteEncode, vkontakteDecode, type VKontakteDecodeResult } from '@dmaximyuk/signature';

const rawLaunchParams = window.location.search.slice(1);
const encoded = vkontakteEncode(rawLaunchParams);

Backend: verify signature and extract data.

const validator = vkontakteDecode({ token: process.env.VK_APP_TOKEN });
const result = validator(encoded);
if (result) {
  console.log(result.userId, result.params);
}

Types

Telegram

interface TelegramUser {
  id: number;
  first_name: string;
  last_name?: string;
  username?: string;
  language_code?: string;
  is_premium?: boolean;
  allows_write_to_pm?: boolean;
  photo_url?: string;
}

interface TelegramDecodeResult {
  userId: number;
  authDate: number;
  queryId: string;
  user: TelegramUser;
}

interface TelegramDecodeOptions {
  token: string;
  maxAge?: number;
}

VKontakte

interface VKontakteUser {
  vk_user_id: number;
  vk_app_id: number;
  vk_ts: number;
  vk_is_app_user: number;
  vk_are_notifications_enabled: number;
  vk_is_favorite: number;
  vk_language: string;
  vk_platform: string;
  vk_ref: string;
}

interface VKontakteDecodeResult {
  userId: number;
  ts: number;
  params: VKontakteUser;
}

interface VKontakteDecodeOptions {
  token: string;
  maxAge?: number;
}

Tests

Requires a .env file with (see .env.example):

• Telegram: TG_BOT_TOKEN, TG_RAW_SECRET
• VKontakte: VK_APP_TOKEN, VK_RAW_SECRET (VK tests are skipped if not set)

bun run test

Tests cover: valid signature from encode, full data from decode, rejection of invalid/tampered signatures and wrong token, plus encode/decode benchmarks.

Benchmarks

Telegram (Apple M4 Pro, 48 GB, bun test):

Operation	Total	Per op	Throughput	n
encode	30.76ms	0.0031ms	325 125 ops/s	10 000
decode	119.42ms	0.0012ms	837 367 ops/s	100 000

Compatibility

• Node.js — full support (decode uses node:crypto)
• Bun.js — full support
• Browser — encode only; no signature verification (decode requires Node/Bun for HMAC)