I Built an API That Writes Code Documentation in 13 Languages — Here's How

I’ve always disliked writing documentation. Not because it’s hard, but because it’s repetitive. You write a function, you describe what it does, you give an example, and then you realize you need the same thing in another language because half your users don’t speak English. So I decided to automate it. The result is an API that takes source code as input and returns a clean Markdown README, API reference, or inline comments — in any of 13 languages. No templates, no manual translation. curl -X POST "https://ai-code-documentation-generator.p.rapidapi.com/demo" \ -H "x-rapidapi-host: ai-code-documentation-generator.p.rapidapi.com" \ -H "x-rapidapi-key: YOUR_KEY" \ -H "Content-Type: application/json" \ -d '{"code":"def add(a,b): return a+b","code_language":"python","doc_language":"en"}' { "success" : true , "documentation" : "# Add Utility \n\n ## Overview \n A simple function to add two numbers..." , "quality_score" : 9 , "target_language" : "en" } It auto-detects the programming language (Python, JavaScript, Go, Rust…) and spits out a polished doc. The English output is solid, but seeing it generate accurate Japanese or German READMEs from the same code still feels like magic. The Tech Behind It Backend: Python + FastAPI, hosted on Northflank. AI Model: DeepSeek (via API). The model actually understands code structure, so generated docs aren’t just generic wrappers. Language Detection: Pygments for syntax highlighting + language guessing. Caching: 24-hour cache to avoid redundant calls and save cost. Security: Sensitive strings (API keys, passwords) are automatically redacted from the output. The whole thing is open source: https://github.com/zhaochangbo888/docgen-api Why I Didn’t Just Use ChatGPT You could absolutely paste your code into ChatGPT and ask for docs. But integrating an LLM directly into a CI/CD pipeline, or a VS Code extension, or a platform that needs programmatic access gets messy with rate limits, authentication, and output consistency. This API giv