xixu-me/deeplx ? reverse-engineered prompt

Build me a self hosted translation service I can deploy on Cloudflare Workers. I want it to feel like a free DeepL style API with no user API keys, and it should support both DeepL quality translation and Google Translate as separate endpoints. Please include simple POST routes for /deepl, /google, and a backward compatible /translate route that maps to DeepL, plus a small /debug route if that helps with checking the service.

The main thing I care about is reliability under heavy use. Add smart proxy rotation or load balancing, caching for repeated text, rate limiting, retries with backoff, and a circuit breaker so it avoids 429 errors and keeps working if one upstream path fails. Make it safe for public use with input validation, CORS, security headers, and clean error responses that do not leak internals.

Please make it production ready, easy to self deploy, and include tests plus a short README with example requests. If anything is unclear, check the current Cloudflare Workers docs online.