Key points
- Read Frog (~5.6K GitHub stars) positions itself as an AI-driven immersive language learning extension. It is licensed under GPLv3 with a commercial dual license and was originally released without a license, then retroactively relicensed on 2026-01-02. Repository: https://github.com/mengxi-ream/read-frog
- KISS Translator is a minimalist, cross-browser translation extension and userscript licensed as open source. It supports Chrome, Edge, Firefox, Kiwi (Android), Orion (iOS), Safari, and Thunderbird, plus Tampermonkey/Violentmonkey scripts. Repository: https://github.com/fishjar/kiss-translator
- Read Frog core features: bilingual/pure translation modes, context-aware translation using page title and Markdown summary, selection toolbar (Translate / Explain / Speak), custom Prompts with dynamic tokens (
[TARGET_LANG],[INPUT],[TITLE],[SUMMARY]), intelligent batch requests (claimed up to 70% token savings with exponential backoff and single-request fallback), 20+ AI providers via Vercel AI SDK, YouTube bilingual subtitles, and free Edge TTS with 150+ voices and 80+ languages. - KISS Translator core features: web bilingual translation, input-box translation, selection translation, hover translation, YouTube subtitles with AI segmentation, AI contextual memory, AI terminology dictionary, three offline modes (Browser BuiltinAI, local Ollama at
http://localhost:11434, 24-hour local cache), aggregation sending, KISS-Worker sync (Cloudflare/Docker self-host), WebDAV sync, and a community rule subscription ecosystem. - KISS Translator ecosystem: kiss-translator, kiss-worker (sync service), kiss-rules (community rules), kiss-proxy (translation API proxy), kiss-dictionary (selection dictionary extension).
- Technical stacks:
- Read Frog:
TypeScript + React + Tailwind CSS + Vite + WebExtension APIwith IndexedDB (Dexie) storage; Firebase sync planned but not yet enabled. Runs entirely locally; users supply their own API keys. - KISS Translator:
src/libs/browser.jsruntime detection for cross-browser compatibility,src/libs/trustedTypes.jsXSS mitigation, offline-first architecture. - Meituan Tabbit copying incident: on 2025-12-30 Meituan's Tabbit team forked Read Frog while the repo had no license; after GPLv3 was added on 2026-01-02, Tabbit launched its browser beta on 2026-03-02 with UI, option order, shortcuts, and internal file names (read-frog-xxx.png) nearly identical to Read Frog. The author posted on Xiaohongshu/X on 2026-03-02/03; Tabbit acknowledged the issue on 2026-03-03, committed to removing translation features, and open-sourced at https://github.com/Tabbit-Browser/read-frog. The original author later granted a free commercial license limited to v1.21.3 and earlier.
- Side-by-side comparison highlights: Read Frog has stronger AI tooling, TTS, and batch token savings; KISS Translator has wider browser support (including mobile), built-in offline translation, userscript version, and a mature rule ecosystem.
- Limits versus commercial alternatives: Neither extension supports PDF translation, EPUB translation, or full-document AI polishing. Open source enables code auditing but does not guarantee an audit has been performed, and browser extensions still have broad access to site data.
- Trend observations: Token economics favor batching short web fragments (system prompt and HTTP overhead amortization); browser built-in AI (Chrome/Edge) is emerging as a no-API, fully local translation path; both projects embody decentralization through user-supplied API keys and community-shared rules.
- Read Frog: https://github.com/mengxi-ream/read-frog
- KISS Translator: https://github.com/fishjar/kiss-translator
- Meituan Tabbit incident summary: https://blog.mzh.ren/zh/posts/2026/02/meituan-tabbit-plagiarize-read-frog/
- Read Frog feature overview (Japanese): https://ai-heartland.com/
- KISS Translator Chrome stats: https://chrome-stats.com/d/jemckldkclkinpjighnoilpbldbdmmlh
- KISS Translator userscript: https://greasyfork.org/