Mastros

Mastros builds privacy-first Chrome extensions that export and download the data you can already see in WhatsApp Web, Telegram Web, LinkedIn, Instagram and TikTok, to Excel, CSV, JSON or JSONL. Every extension runs entirely in the browser. Nothing is uploaded to a Mastros server, no API keys or developer credentials are needed, there is no second login, and nothing is automated: the extensions never send messages, never invite anyone, never auto-reply and never broadcast. They read what your own signed-in session already displays and save it to a file. What each extension does: Telegram: exports group members, chat messages, recent contacts and mutual groups, and bulk-downloads photos, videos, documents, audio and voice notes from any chat or channel you can open. You choose how many messages to scan, and every item carries its type and date so a run can be narrowed to the media and period you want. WhatsApp: exports group members, chat messages and your full contact list from WhatsApp Web, and downloads a conversation's photos, videos and voice notes in bulk. Hidden phone numbers are never revealed, and it does not use the WhatsApp Business API. LinkedIn: exports Profile, Company, Jobs and Posts search results, plus Sales Navigator Lead and Account searches, as structured files for recruiting, lead generation and CRM import. It never guesses email addresses. Instagram: exports followers and following, including a separate file of who doesn't follow you back, post comments with author, likes and timestamp, post likers, and posts, reels and stories with captions, counts and dates. It works on any page you can already open: a profile, a post or reel, the followers dialog, search, hashtags and Explore. It bulk-downloads photos, videos, reels, stories and highlights in original quality, and calculates Instagram engagement rate with the formula shown on screen. TikTok: exports creators, videos, comments and hashtag or search results, with an exact engagement rate computed from TikTok's real counts rather than the rounded figures shown on screen (a "3.1K" comes through as 3,086). Creator search pulls the email and website a creator publishes in their bio. Every run saves as a dataset you can filter before exporting, and you can download a single video or a whole creator, hashtag or search as one ZIP with a metadata file mapping each clip back to its row. Runs resume and deduplicate. What makes it different: flat monthly plans instead of per-record credits, a free plan for small exports, a strict read-only design, and a free engagement rate calculator for Instagram and TikTok that works on any public profile with no extension installed. Where WhatsApp's own Export Chat stops at roughly 40,000 messages and counts backward from the most recent, Mastros exports what you choose, in a format a spreadsheet opens directly. Who uses it: growth and lead-gen teams building lists, recruiters exporting candidate searches, creators and influencer marketers screening accounts by real engagement, community managers keeping member records, researchers collecting chat data, and people archiving a channel, backing up conversations before switching phones, or pulling shared media out of a group. Mastros is not affiliated with WhatsApp, Meta, Telegram, LinkedIn, Instagram, TikTok or ByteDance.