Libraries and SDKs
Code you import rather than software you run.
LlamaIndex
A Python framework for retrieval only. It connects a model to your own documents, databases or APIs, and does not try to chain everything.
Tested on Claude Sonnet · Jun 2026
Vercel AI SDK
A TypeScript library for streaming model responses into a web UI. Hooks handle the streaming and state so you do not build them by hand.
Tested on GPT-5 · Jun 2026
LangChain
A Python and JavaScript framework for chaining prompts, tools and retrieval into a pipeline, with a large set of ready-made integrations.
Tested on GPT-5 · Jun 2026
Instructor
A small Python library that forces a model output into a Pydantic schema and retries automatically when the response fails validation.
Tested on Claude Sonnet · Jun 2026
Haystack
An open-source Python framework from deepset for production retrieval and search pipelines, with more explicit pipeline control than most…
Tested on GPT-5 · Jun 2026