Telegram bot in TypeScript: writing a smart assistant from scratch

Introduction: why TypeScript and not Python?

Hello, developer! If you are reading this on PythonLib, you are probably surprised: "Why an article about TypeScript on a Python resource?" The answer is simple: the IT world does not tolerate boundaries, and a good developer knows how to go beyond one language. TypeScript is not just a "superset of JavaScript", it is a powerful tool for creating reliable, scalable, and predictable applications. And Telegram bots are the perfect sandbox to try it out.

Imagine: you write code, and the IDE highlights errors in advance, data types prevent runtime crashes, and autocompletion works like a Swiss watch. This is not magic — this is TypeScript. In this guide, we will create a full-fledged Telegram bot in TypeScript from scratch: from registration in BotFather to deployment. You will learn how to set up a project, handle commands, send messages, and work with external APIs.

Ready? Then let's go!

Why choose TypeScript for a Telegram bot

Before diving into the code, let's figure out why you should write a bot in TypeScript rather than Python, which, it would seem, is the "native" language for such tasks.

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• Typing is your friend. When a project has 10+ commands and 20 handlers, TypeScript will save you from silly mistakes like passing a string instead of a number.
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• Modern syntax. Async/await, destructuring, modules — all this makes the code cleaner and more readable.
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• Node.js ecosystem. A huge number of libraries, including Telegraf (the best framework for bots).
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• Performance. Node.js is an event-driven platform, ideal for chat bots with high loads.
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By the way, about Telegraf: it is a TypeScript-first framework that makes working with the Telegram Bot API as simple as possible. We will be using it.

Preparation: what you need to install

To get started, you will need:

# Make sure Node.js (version 18+) and npm are installed\nnode -v\nnpm -v\n\n# Create a project folder\nmkdir telegram-bot-ts\ncd telegram-bot-ts\n\n# Initialize the project\nnpm init -y

Now let's install the dependencies:

npm install telegraf dotenv\nnpm install -D typescript @types/node ts-node nodemon

Let's break down what we installed:

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• telegraf — the main framework for the bot.
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• dotenv — for storing the token in a .env file (security first).
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• typescript, @types/node, ts-node — for compiling and running TS.
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• nodemon — for automatic restart on changes.
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Create a tsconfig.json file:

{\n  "compilerOptions": {\n    "target": "ES2020",\n    "module": "commonjs",\n    "strict": true,\n    "esModuleInterop": true,\n    "skipLibCheck": true,\n    "forceConsistentCasingInFileNames": true,\n    "outDir": "./dist"\n  },\n  "include": ["src/**/*"],\n  "exclude": ["node_modules"]\n}

And a .env file (don't forget to add it to .gitignore!):

BOT_TOKEN=your_token_from_BotFather

Bot registration: getting to know BotFather

This is the easiest step. Open Telegram, find @BotFather and send the command /newbot. Follow the instructions:

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1. Enter the bot's name (e.g., "My Smart Assistant").
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2. Enter a username (must end with bot, e.g., my_smart_helper_bot).
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3. Copy the received token and paste it into .env.
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Done! Now you have the key to the Telegram API.

Project structure and first launch

Create a src folder and inside it a file index.ts:

// src/index.ts\nimport { Telegraf } from 'telegraf';\nimport { mess