Free Grammar & Spell Checker

Check grammar, typos, punctuation, and writing style in real time. Runs 100% locally on your device via WebAssembly — your text never leaves your browser.

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How to use Free Grammar & Spell Checker

  1. 1

    Type, paste, or load your draft into the editor pane.

  2. 2

    Choose your preferred English dialect (American, British, Canadian, Australian) or format (Plain Text, Markdown).

  3. 3

    Click on any highlighted issue in the text or review cards in the sidebar to view suggestions.

  4. 4

    Click a suggested fix to replace the word instantly, or use "Fix All" to resolve all mistakes at once.

  5. 5

    Copy your polished text with one click or download as a text file.

Why use this tool?

100% Private & Client-Side

Powered by Harper compiled to WebAssembly. Your documents, essays, and confidential emails are analyzed locally and never transmitted to external cloud servers.

Lightning-Fast Sub-10ms Feedback

Built on high-performance Rust algorithms, returning spelling corrections and grammatical rules virtually instantaneously as you type.

Code & Markdown Aware

Intelligently respects Markdown formatting, code blocks, links, and technical prose without flagging valid code syntax as spelling errors.

Multiple English Dialects

Easily switch between American, British, Canadian, and Australian English conventions (such as color vs colour, analyze vs analyse).

Frequently asked questions

Is this grammar checker completely free?

Yes. UsefulGo Grammar Checker is 100% free with unlimited words and no account or subscription required.

Does UsefulGo send my writing to an AI or cloud server?

No. The entire grammar engine runs locally inside your browser via WebAssembly (WASM). Your text never leaves your device.

Can I check Markdown documents without breaking syntax?

Yes. Switch the format to Markdown mode to automatically skip code blocks, backticks, and URLs while proofreading surrounding sentences.

How does it compare to cloud-based tools like Grammarly?

Unlike cloud tools that transmit your keystrokes to remote servers, this tool executes on-device with zero latency, zero telemetry, and total privacy for sensitive documents.

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