BirdNest Tech Talk

Oct 10, 2025 · Artificial Intelligence

How to Build a Custom Output Parser in LangChain for Non‑Standard LLM Formats

This guide explains why custom output parsers are needed for LangChain when dealing with non‑JSON or XML responses, walks through inheriting BaseOutputParser, implementing parse() and optional format instructions, and provides a complete Python example that converts a simple "Key: Value" string into a dictionary.