What is kiss-translator?

KISS Translator is a browser extension and Greasemonkey userscript that adds bilingual translation to web pages. "Bilingual" here means it shows both the original text and the translated version side by side on the page, rather than replacing the original. The project is open source and the README is written primarily in Chinese, though English and Japanese versions are linked. The extension works in Chrome, Edge, Firefox, Kiwi on Android, Orion on iOS, and Thunderbird. The userscript version works in standard userscript managers like Tampermonkey and Violentmonkey, as well as iOS Safari through a separate installer. The authors recommend the browser extension over the userscript for a more complete experience, noting the userscript can run into cross-origin restrictions. For translation, the tool connects to a large range of external services you configure yourself: Google, Microsoft, Tencent, Volcengine, DeepL, DeepLX, OpenAI-compatible endpoints (which covers OpenAI, local Ollama models, DeepSeek, OpenRouter, and others), Gemini, Claude, AzureAI, and CloudflareAI. Beyond translating the main body of a web page, it also handles text inside input fields, selected text via a popup, hover translation for individual paragraphs, and YouTube subtitle translation with options to merge subtitle segments before translating. Settings can be synced across devices using either a self-hosted companion service called KISS-Worker (deployable on Cloudflare or Docker) or a WebDAV server. Translation rules can be customized per-site, and you can subscribe to community-maintained rule sets from a separate repository. Keyboard shortcuts are configurable through the browser's own extension shortcuts settings. The project is a personal side project, with the README noting there is no strict development schedule and that community contributions are welcome.