Quill Checker

Real-time British English grammar, spelling and style checking in your browser. Powered by your own infrastructure.

Get the Extension

Your grammar. Your infrastructure.

✓ British English First

Built for en-GB from the ground up. Catches spelling and grammar that US-centric tools miss.

✓ Self-Hosted API

All text checking runs on your own server. No data sent to third parties. Full privacy control.

✓ Inline Underlines

Red wavy underlines appear directly in textareas and contentEditable fields — like a native grammar tool.

✓ Custom Dictionary

Add words to your personal dictionary. Syncs across all your devices via Chrome storage.

Public API

Self-hosted LanguageTool endpoint — free to use, no API key required.

POST https://quillchecker.com/lt/v2/check

# Check text for grammar errors
curl -X POST https://quillchecker.com/lt/v2/check \
  -d "language=en-GB&text=This are a test with a error."

# Response
{
  "matches": [
    { "message": "The singular 'this' does not agree..." },
    { "message": "Use 'an' instead of 'a' before 'error'" }
  ]
}