DSPy

DSPy is an open-source Python framework (MIT license, ~38,500 GitHub stars) that replaces hand-crafted prompt strings with declarative, composable modules for programming language models. Instead of brittle prompt templates, developers define typed signatures and chain modules (e.g., dspy.ChainOfThought, dspy.ReAct) into pipelines. DSPy's optimizers (formerly "teleprompters") then automatically tune prompts and/or fine-tune weights against a metric, eliminating manual prompt engineering. It supports classifiers, retrieval-augmented generation (RAG) pipelines, and multi-step agent loops. Installable via pip install dspy-ai; self-hostable with any compatible LM backend.