# Mastros.online — Telegram Data Extractor

> Mastros.online is a Chrome extension that extracts Telegram members, messages, and contacts from chats you already have access to. It operates entirely client-side with an optional Power Mode that connects directly to the Telegram MTProto API for deeper, more complete data extraction. No external server processes your data.

## What It Does

Mastros.online lets marketers, researchers, and community managers extract structured data from Telegram Web. It injects a sidebar into web.telegram.org and provides four extraction modes: Group Members (API-powered), Chat Messages (Web + API), Recent Contacts (Web + API), and Mutual Groups (API-powered). All extracted data exports as CSV, JSON, or JSONL.

- It is a Chrome Extension (Manifest V3), not a standalone app or SaaS platform
- It works only on web.telegram.org — it does not work on Telegram Desktop or mobile apps
- Power Mode uses the user's own Telegram API credentials (api_id and api_hash from my.telegram.org) to connect via MTProto using GramJS
- Web Mode reads visible DOM elements from the open Telegram Web tab — no API credentials needed
- All data processing happens in the browser. No user data is sent to Mastros servers
- It is not affiliated with Telegram

## Extraction Modes

- **Group Members** (Power Mode only): Extracts full member profiles from one or multiple Telegram groups via the Telegram API. Supports current group, manual handle input, or browsing your group list. Collects: name, username, user ID, role, bio, phone (if visible)
- **Chat Messages** (Web Mode + Power Mode): Extracts message history from any open chat. Collects: message text, sender name, sender ID, timestamp, reply/forward metadata. Web Mode scrolls and reads DOM; Power Mode fetches via API for faster, more complete results
- **Recent Contacts** (Web Mode + Power Mode): Extracts profile info from your N most recent chat conversations. Options to ignore pinned chats and exclude bots
- **Mutual Groups** (Power Mode only): Finds shared groups between you and a target user, then optionally extracts members from those groups

## Export Formats

All extracted data can be exported as CSV, JSON, or JSONL. Profile fields include: name, handle, telegram_user_id, role, bio, phone, source_group, source_chat, scraped_at, source_mode. Message fields include: message_id, timestamp, text, sender_id, name, handle, bio, phone, source_chat, scraped_at, source_mode.

## Plans & Pricing

- **Free**: 500 profiles/month, 1,000 messages/month. Power Mode available for Group Members and Mutual Groups
- **Pro**: 5,000 profiles/month, 10,000 messages/month. Power Mode for all extractors including Chat Messages and Recent Contacts
- **Scale**: 100,000 profiles/month, 500,000 messages/month. Power Mode for all extractors

## Technical Details

- Chrome Extension, Manifest V3
- Content script injects sidebar into web.telegram.org
- Power Mode uses GramJS (browser MTProto client) running inside the extension's iframe
- Session strings are stored locally in chrome.storage — no server-side session storage
- Backend API at telegram-scraper-api.mastros.workers.dev handles account sync, quota tracking, and billing via Stripe
- Analytics via PostHog (anonymized usage telemetry)
- Current version: 4.0.0

## Key Pages

- [Mastros.online Homepage](https://mastros.online): Main landing page and product overview
- [Privacy Policy](https://mastros.online/privacy): How user data is handled
- [Terms of Service](https://mastros.online/terms): Usage terms and conditions
- [Support](mailto:admin@mastros.online): Email support contact

## Important Notes

- Users are responsible for compliance with Telegram's Terms of Service
- The extension extracts data only from chats the user already has access to
- Power Mode requires the user's own Telegram API credentials — the extension does not provide or share API keys
- No scraping of private chats or channels the user is not a member of