About

AI writing assistants are getting better every day. Millions of people now ask ChatGPT, Claude, or Gemini to rewrite their emails, cover letters, contracts, and articles. But once the AI rewrites your text, how do you know exactly what changed?

Re-reading the entire document takes time and leaves room for error. Copying both versions into a developer tool like git diff is out of reach for most people. What AI Done was built to fill that gap.

Paste your original text and the AI-edited version — the diff appears instantly as you type. See every addition, deletion, and moved paragraph highlighted side by side, without any sign-up and without sending your text to any server.

The diff runs entirely in your browser using a Myers difference algorithm — the same family of algorithms used in Git and VS Code. It compares paragraphs first, then drills down to individual words for modified sections.

• Green — text added by the AI
• Red — text removed by the AI
• Yellow — paragraphs moved to a different position
• Unchanged text is shown in full so you keep context

You can also restore individual changes you don't want to keep, then copy the final version with one click.

Beyond visual comparison, What AI Done includes a right-click AI menu directly in the editor. Select any text in the right column and right-click to access three actions:

• Rephrase — rewrites the passage while preserving meaning, tone, and language
• Simplify — shortens sentences and simplifies vocabulary
• Free prompt — you give the instruction, the AI executes it

The suggestion is inserted below the original text. You can accept it, reject it, or preview a side-by-side diff before deciding. These features require an API key (OpenAI or Anthropic) configured in the AI settings.

Your documents never leave your device. The extraction and comparison algorithms run as JavaScript in your browser tab. No text is stored, indexed, or transmitted.

Exception: when you use the AI actions, the selected text passage is sent to the AI provider you have configured (OpenAI or Anthropic). The full document never leaves your device.

• Plain text & documents — .txt, .md, .mdx, .rst, .tex, .csv, .log
• Source code — JavaScript / TypeScript (.js, .jsx, .ts, .tsx, .mjs, .cjs), Python (.py), Ruby (.rb), PHP (.php), Java (.java), Kotlin (.kt), Swift (.swift), Go (.go), Rust (.rs), C / C++ (.c, .cpp, .h, .hpp), and more
• Web & markup — .html, .css, .scss, .vue, .svelte, .svg, .xml
• Config & data — .json, .yaml, .yml, .toml, .ini, .env, .sql, .graphql
• Shell & scripts — .sh, .bash, .zsh, .ps1, .bat
• Word documents (.docx) — text extracted locally in your browser
• PDF files (.pdf) — native PDFs only; scanned pages are not supported

All formats are processed entirely in your browser — nothing is uploaded. Limits: 50 MB per file · 500,000 characters of content.

The core diff tool is and will always be free. No account, no paywall, no ads on the diff itself.