Oppenly: Grammar Checker & Writing Assistant

Grammar, clarity and tone suggestions on almost any website. Runs on your device. Free and open source.

Oppenly checks your writing as you type on almost any website and fixes mistakes in one click. It runs on your device: no account, no tracking, and your text is not sent anywhere to be checked. WHAT IT CHECKS • Correctness: spelling, grammar, punctuation, verb forms and commonly confused words • Clarity: wordy phrases, passive voice and hard-to-read sentences • Engagement: bland, overused and repeated words • Delivery: tone, confidence, politeness and inclusive language HOW IT WORKS • Coloured underlines appear in text boxes and rich-text editors as you type. • Hover an underline to see the fix and a short explanation, then click to apply it. • Click the Oppenly button in the corner of a text box to see every suggestion, accept all spelling and grammar fixes at once, check the tone and see an overall score. • Select text to make it shorter, more formal, friendlier or more confident. • Set goals for your audience, formality, domain and intent, and choose American, British, Canadian, Australian or Indian English. • Pause Oppenly for an hour, or turn it off on a site, from the button in the text box. PRIVATE BY DESIGN • Checking runs inside your browser, powered by the open-source Harper grammar engine and Oppenly’s own style rules. It also works offline. • No account, no analytics and no ads. Oppenly has no servers. • Your settings and personal dictionary stay on your computer. OPTIONAL AI, YOUR CHOICE Connect an AI provider for context-aware suggestions and full rewrites with your own API key: OpenAI, Anthropic, Google Gemini and 14 more, or a model that runs on your computer. Oppenly asks for your consent before any text is sent, and sends it only to the provider you chose. There are no prompt limits. GOOD TO KNOW • Oppenly does not work in Google Docs yet. • Free and open source under the Apache 2.0 license. Source code, issues and privacy policy: https://github.com/shivashis-adhikari/Oppenly