Stop using regex to fix LLM JSON. I built a middleware for it.

If you are building an AI wrapper, a RAG pipeline, or working with Agentic AI, you already know the dirtiest secret in the space: LLMs are terrible at returning reliable JSON. You can use OpenAI's JSON mode. You can write strict system prompts. But eventually, in a production environment, the model will hallucinate a trailing comma, use single quotes, or just forget a closing bracket. And when that hits your Node backend? JSON . parse ( llmOutput ); // 💥 Crashes your Express server thread. I got tired of writing brittle Regex hacks to catch trailing commas, so I built a dedicated API and open-sourced the SDKs to fix it permanently. Here is how I built a "Reliability Layer" that auto-repairs JSON and validates it against a schema before it ever touches your database. Why "Just use Regex" is a trap When we first hit the SyntaxError: Unexpected token bug, the reflex is to write a utility function: Strip the ``` json markdown. Regex out the trailing commas. This works until the LLM nests a