Alex

Posted on Mar 8

I Built a Telegram Bot That Writes Cover Letters for $0.14

#telegram #ai #bot #tutorial

Job applications are tedious. You find a great role, then spend 30 minutes writing a cover letter that probably won't get read. I built a Telegram bot that does it in 10 seconds for $0.14.

Here's exactly how it works and how you can build something similar.

The User Flow

User opens @avatrix_ai_bot on Telegram
Types /cover and pastes a job description
Bot asks for their resume highlights
User pays with Telegram Stars (roughly $0.14)
Bot generates a tailored cover letter in 10 seconds
User copies it and applies

No signups. No credit cards. No friction.

Tech Stack

Runtime: Node.js with node-telegram-bot-api
AI: Claude API for letter generation
Payments: Telegram Stars (built-in, no Stripe needed)
Hosting: PM2 on a server (could use Railway or Fly.io)

Step 1: Set Up the Bot

mkdir telegram-bot && cd telegram-bot
npm init -y
npm install node-telegram-bot-api

Create your bot with @BotFather on Telegram. Get the token.

// src/index.ts
import TelegramBot from 'node-telegram-bot-api';

const bot = new TelegramBot(process.env.TELEGRAM_BOT_TOKEN!, {
  polling: true,
});

bot.onText(/\/start/, (msg) => {
  bot.sendMessage(msg.chat.id,
    'I write tailored cover letters using AI.\n\n' +
    'Commands:\n' +
    '/cover - Generate a cover letter\n' +
    '/help - How it works'
  );
});

Step 2: Handle the Cover Letter Flow

The conversation has three steps: get the job description, get the user's background, generate the letter.

const sessions = new Map<number, { step: string; jobDesc?: string }>();

bot.onText(/\/cover/, (msg) => {
  const chatId = msg.chat.id;
  sessions.set(chatId, { step: 'awaiting_job' });
  bot.sendMessage(chatId, 'Paste the job description:');
});

bot.on('message', async (msg) => {
  const chatId = msg.chat.id;
  const session = sessions.get(chatId);

  if (!session) return;

  if (session.step === 'awaiting_job') {
    session.jobDesc = msg.text;
    session.step = 'awaiting_resume';
    bot.sendMessage(chatId,
      'Now paste your key skills and experience (a few bullet points is fine):'
    );
  } else if (session.step === 'awaiting_resume') {
    // Trigger payment before generating
    await requestPayment(chatId, session.jobDesc!, msg.text!);
  }
});

Step 3: Telegram Stars Payment

Telegram Stars let users pay without leaving the app. No Stripe integration needed.

async function requestPayment(
  chatId: number,
  jobDesc: string,
  resume: string
) {
  await bot.sendInvoice(chatId, 'Cover Letter', 'AI-generated tailored cover letter', 'cover_letter', '', 'XTR', [
    { label: 'Cover Letter', amount: 1 }, // 1 Star ≈ $0.014
  ]);

  // Store data for after payment
  sessions.set(chatId, {
    step: 'awaiting_payment',
    jobDesc,
    resume,
  });
}

bot.on('pre_checkout_query', (query) => {
  bot.answerPreCheckoutQuery(query.id, true);
});

bot.on('successful_payment', async (msg) => {
  const chatId = msg.chat.id;
  const session = sessions.get(chatId);
  if (!session) return;

  bot.sendMessage(chatId, 'Payment received! Generating your cover letter...');

  const letter = await generateCoverLetter(
    session.jobDesc!,
    session.resume!
  );

  bot.sendMessage(chatId, letter);
  sessions.delete(chatId);
});

Step 4: AI Generation

async function generateCoverLetter(
  jobDesc: string,
  resume: string
): Promise<string> {
  const response = await fetch('https://api.anthropic.com/v1/messages', {
    method: 'POST',
    headers: {
      'content-type': 'application/json',
      'x-api-key': process.env.ANTHROPIC_API_KEY!,
      'anthropic-version': '2023-06-01',
    },
    body: JSON.stringify({
      model: 'claude-sonnet-4-20250514',
      max_tokens: 1024,
      messages: [{
        role: 'user',
        content: `Write a professional cover letter for this job:

Job Description:
${jobDesc}

Candidate Background:
${resume}

Rules:
- 3-4 paragraphs
- Match skills to job requirements
- Professional but not stuffy
- Include a specific detail from the job description
- End with a clear call to action`,
      }],
    }),
  });

  const result = await response.json();
  return result.content[0].text;
}

Step 5: Deploy

npm install -g pm2
pm2 start dist/index.js --name "cover-bot"
pm2 save
pm2 startup

The bot runs 24/7 and restarts automatically if it crashes.

Economics

Each cover letter costs about $0.003 in AI API fees. Users pay 10 Stars ($0.14). That's a 97% margin per request.

At 10 letters/day, that's $1.40 revenue and $0.03 in costs. Not life-changing, but it compounds. And the bot runs itself — no customer support, no manual work.

Expanding the Bot

Once the cover letter flow works, add more services:

bot.onText(/\/services/, (msg) => {
  bot.sendMessage(msg.chat.id,
    'Available services:\n\n' +
    '/cover - Cover letter ($0.14)\n' +
    '/resume - Resume review ($0.28)\n' +
    '/linkedin - LinkedIn summary ($0.14)\n' +
    '/email - Professional email ($0.07)'
  );
});

Each service follows the same pattern: collect input, charge Stars, generate with AI.

Why Telegram?

Telegram has 900M+ monthly users. Payments are built in. No app store approval. No website needed. Users can find your bot through search or shared links.

The friction is near zero: tap a link, tap a button, paste text, pay with Stars. No account creation, no credit card forms, no page loads.

Try It

The live bot is at @avatrix_ai_bot. Try the /cover command to see the full flow in action. Or build your own using the steps above.

Built by Avatrix LLC. Also available as a web app at CoverCraft.

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