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CoWriter AI vs Grammarly

Two fact sheets from our own research, side by side — pricing, platforms, API access and status re-checked by us rather than quoted from the vendors. CoWriter AI starts at $11.99, Grammarly at $12. Only Grammarly has a free tier.

CoWriter AIStudent writing workspace with drafting, citation generators, plagiarism checks and AI-detection evasion.GrammarlyGrammar, tone and rewriting help inside every app

Side by side

FactCoWriter AIGrammarly
CategoryEssay & Assignment HelpGrammar & Proofreading
Pricing modelPaidFreemium
Starts at$11.99 month$12 month
Public APINoNo
PlatformsWebWeb, Chrome Ext, Windows, macOS, iOS, Android
CompanyProtonLabs Technology IncSuperhuman
Launched—2009
Last verifiedSep 6, 2026Sep 6, 2026

What our research says

CoWriter AI

Bundles the things a student actually opens five tabs for — drafting, citations, plagiarism check — into one $11.99 workspace, and the free citation generators are useful on their own. The terms are where this turns sour: no refunds under any circumstances and an explicit request that you waive chargeback rights. That, plus the AI-detection-evasion pitch, makes it a tool to enter with eyes open.

Pros

  • Citation generators for APA, MLA, Chicago, IEEE, Harvard, Vancouver, CSE and more
  • Plagiarism detection and grammar checking alongside drafting
  • Free standalone tools usable without a subscription
  • Named legal entity, ProtonLabs Technology Inc, in the footer

Cons

  • Terms state all sales are final with no refunds, credits or pro-rata reimbursement
  • Terms ask users to waive the right to dispute or charge back any transaction
  • Markets AI-detection evasion, which conflicts with most academic integrity policies
  • No country, address or API published

Grammarly

Still the default for catching mistakes inside other people's software, but the free tier has quietly become an AI-prompt meter and the honest price is $30 unless you commit to a full year.

Pros

  • Runs inside the apps people already write in rather than as a separate editor
  • Free tier still covers spelling, grammar and tone detection with no time limit
  • Pro folds in plagiarism and AI-text detection that rivals charge for separately

Cons

  • The $12 headline is the annual rate; paying monthly costs $30
  • Free AI allowance is 100 prompts a month and depletes quickly
  • No public API, so it cannot be embedded in another product
  • Enterprise pricing is not published anywhere on the site

Which one fits

Choose CoWriter AI if you need

  • Students juggling citation formats across assignments
  • Anyone who wants drafting and plagiarism checking in one place
  • Users who want free standalone citation generators

Choose Grammarly if you need

  • Anyone writing in a browser, Word or email who wants corrections in place
  • Teams enforcing a house style guide across people who are not writers
  • Non-native English speakers who want fluency rewrites, not just error flags

More comparisons

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