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Mastros vs Private Writing Assistant

A side-by-side comparison built from both listings. Blank cells mean the company has not given that detail; we never guess.

Mastros compared with Private Writing Assistant
DetailMastros logo MastrosPrivate Writing Assistant logo Private Writing Assistant
What it doesPrivacy-first Chrome extensions that export chat and social media data to spreadsheets Spelling and grammar checks in 101 languages, run entirely on your device
StageStartup Not given
Founded2026 Not given
Based inNot given Not given
Pricing modelFreemium Free
PricingFree: 100 profiles and 100 messages per month (WhatsApp), or 250 profiles and 300 messages per month (Telegram), or 250 records (LinkedIn). Instagram and TikTok free and unlimited in beta. Pro: $9/month with 5,000 profiles and 10,000 messages per month (WhatsApp), or 5,000 records (LinkedIn). Scale: Not given
Key features
  • Export group members and chat messages to CSV, JSON or JSONL
  • Bulk media download from chats
  • Export LinkedIn searches with Sales Navigator support
  • Extract email and website from Instagram and TikTok bios
  • Calculate exact TikTok engagement rates
  • Process all data in the browser with no server involvement
  • Read-only with no automation or message sending
  • 101 languages supported with automatic language detection
  • Runs on device using Chrome's built-in AI model
  • Works in email drafts, Google Docs, and Google Slides
  • Fix single mistakes or all corrections at once
  • Toggle checking on and off with visible AI status
What makes it different
  • Works with no account creation, API key or password required
  • Reads only visible data; cannot reveal hidden information or deleted messages
  • Five tools with the same pricing model and interface
  • Instagram and TikTok extensions are free and unlimited during beta
  • Nothing sent to servers - all processing happens on your device
  • Supports 101 languages with automatic detection
  • Uses Chrome's native AI - no external model required
  • Works seamlessly across text boxes, email, docs and slides
Free planNot given Not given
Open sourceNot given Not given
PlatformsNot given Not given
Public APINot given Not given
Community votes00
DR (Domain Rating by Ahrefs)35 no change since last checkNot checked yet no change since last check
Trust Flow (Majestic)100
Citation Flow (Majestic)280
Referring domains (Majestic)540

4 details filled in for both companies.

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