Harper vs MerciApp

Harper is a free, open-source grammar checker that flags capitalization, spelling, awkward phrasing, and grammar errors. The maker says checks run locally, with no cloud round-trips, telemetry, or LLM in the loop, and that suggestions appear in under 10 ms. Harper is available through browser and editor extensions, a language server, a JavaScript library, a Rust crate, and native apps. Listed integrations include Chrome, Brave, Edge, Firefox, VS Code, Cursor, Obsidian, WordPress, Neovim, Zed, Helix, Emacs, and Sublime Text. Its language support covers English and British, American, Canadian, Australian, and Indian English dialects. Harper Desktop lets users toggle rules, add dictionary entries, select a dialect, and turn checking on or off per app. The desktop app is labeled beta for macOS 14 or later, and the Windows desktop app is also described as a beta; its binary was not signed at the time of the listed post. Harper is free, with no account or credit card required.

MerciApp is an AI writing assistant for spelling, grammar, context, and style corrections, with tools for rewriting text. Smart Autocorrect addresses errors in spelling, structure, and grammar as users type. Transform offers ready-made and customizable assistants for rewriting, structuring, and translation, while Dynamic Snippets insert reusable or personalized text using keyboard shortcuts. The browser extension works with Chrome, Firefox, and Edge and integrates with tools including Gmail, Slack, Facebook, WordPress, Salesforce, and HubSpot. Word and Outlook extensions are also available. MerciApp Correct supports French, Spanish, Italian, German, and Portuguese. The maker says texts are not used to train its AI and says data is hosted in France, kept private, and not shared with third parties. The free plan analyzes 600 words per day and allows three Transform rewrites per day. Assist costs €12 a month, with an annual option shown at 144€/year per seat; Enterprise requires at least 20 seats, with no price listed.