Model
Paste your text and get inline, per-span corrections with one-line reasons. Bring your own API key — your text and key never leave your browser. At ~$0.0006 per polish, a year of heavy use costs under $2 — versus Grammarly's $144.
Paste your own API key for DeepSeek, Gemini, GLM, or Kimi. No accounts, no subscription. At DeepSeek V4 Flash rates, one polish costs about $0.0006 — the $144 you'd spend on a year of Grammarly buys 200,000+ polishes.
Your text and API key stay on your device. We have no backend database and do not log your input.
Each correction is pinned to the exact span in your text. Accept, reject, or accept-all directly in the editor.
Switch between DeepSeek, Gemini, GLM, Kimi, or any OpenAI-compatible endpoint. Add custom providers in one click.
Your last 50 polish tasks persist in localStorage. Re-open any task to restore the original text and all suggestions.
Self-host or audit the code on GitHub. No tracking pixels, no analytics sold to third parties.
Paste your abstract, introduction, or any paragraph into the editor and click Polish. Grammar Checker returns inline corrections for grammar, spelling, punctuation, and style, each with a short explanation. It is suitable for proofreading essays, research papers, and dissertation drafts before submission.
Yes. Grammar Checker handles personal statements, statements of purpose, and scholarship essays the same way as any other text. Because it runs in your browser with your own API key, we have no persistent backend — your essay text is never stored, logged, or cached.
Yes. IELTS Task 1, Task 2, and TOEFL Independent Writing responses can be pasted directly. Corrections are tagged by type — grammar, word-choice, clarity — so you can see which errors most affect your band score.
Yes. Grammar Checker is well suited for proofreading professional emails, reports, and Slack messages. The 'style' and 'clarity' correction categories catch tone and conciseness issues that pure grammar checkers miss.
Paste one section at a time (5,000–10,000 characters works best) and click Polish. Review the inline suggestions, accept the ones you agree with, and copy the cleaned text back to your document.
Your text is processed in the browser and sent to the LLM provider you configured (DeepSeek, Gemini, GLM, or Kimi). We run no persistent backend — nothing you type is stored, logged, or cached.
Grammarly requires an account and routes your text through its servers. Grammar Checker is a free, open-source BYOK tool: you bring your own LLM API key, the editor runs in your browser, and there is no signup. It supports DeepSeek, Gemini, GLM, and Kimi, letting you pick the model that best fits your writing.
BYOK stands for 'Bring Your Own Key'. Instead of paying a subscription, you paste an API key from a provider like DeepSeek or Gemini. You pay the provider directly for tokens — typically much cheaper than a grammar-tool subscription.
Using DeepSeek V4 Flash official pricing ($0.14 per million input tokens, $0.28 per million output tokens): polishing a ~400-word English passage consumes about 1,800 input tokens (including the system prompt) and 1,200 output tokens (the corrections JSON), for a per-polish cost of roughly $0.0006 — it would take about 1,600 polishes to spend one US dollar. Short emails cost less, and even 500+ word passages rarely exceed $0.001. Other models (Gemini, GLM, Kimi) are slightly pricier but in the same order of magnitude.
Grammarly Pro costs $144/year ($12/month). The same $144 buys 200,000+ polishes on DeepSeek V4 Flash. A heavy user (English emails plus assignments every day, around 1,500–3,000 polishes/year) typically spends under $2/year on LLM tokens — less than 2% of Grammarly's annual price. Even a power user polishing 50 times a day would spend only ~$11/year.
Out of the box: DeepSeek, Kimi (Moonshot), GLM (Zhipu), and Google Gemini. You can also add any OpenAI-compatible endpoint as a custom provider, or any Gemini-compatible endpoint, in the settings panel.
No server-side storage. Your API key, text, and last 50 task snapshots live in your browser's localStorage. Clearing your browser data erases everything.