Alternatives to Vercel AI SDK

Go SDK for AI apps: one type-safe API for text generation, streaming, tools and MCP across 25+ LLM providers.

Open-source Python library that constrains LLM decoding so JSON, regex, and grammar outputs are valid on the first call.

Open-source Python library that constrains LLM output with regex, context-free grammars, and inline control flow.

xsAI is an extra-small OpenAI-compatible AI SDK for JavaScript and TypeScript — 13.1 KB gzipped with every package included.

Free, MIT-licensed OpenAI API examples and Python notebooks for developers building with the OpenAI API.

Rig is an open-source Rust LLM framework for building type-safe AI agents with one unified API across 20+ model providers.

Open-source Rust library for building streaming, parallel LLM pipelines — data indexing, retrieval-augmented generation, and autonomous agents.

Build agentic AI apps in TypeScript, Go, Python, or Dart with Genkit's open-source AI SDK.

Build production AI agents with open source Python and TypeScript harness SDKs you fully control.

Open-source Python library for loading, fine-tuning, and running transformer models across text, vision, audio, and video.

SwiftOpenAI is an MIT-licensed Swift package for calling the OpenAI API with native async/await and Combine on iOS, macOS, and visionOS.

Ruby gem for running open source LLMs locally through Ollama's API, with streaming, embeddings, and token tracking built in.

Eino is an open-source Go LLM framework from ByteDance for building agents, graphs, and RAG pipelines in your existing Go backend.

OpenUI turns AI agent responses into streaming generative UI built from your own component library.

Mellea turns type-annotated Python functions into validated, testable LLM calls with token-level constrained decoding.

A headless React hooks library that runs Vicuna-13B chat entirely in your browser via WebGPU, with no prompt or completion leaving the client.

Open-source (MIT) MCP testing and full-stack MCP App framework for building ChatGPT Apps and Claude Connectors from one React codebase.

Open Harness is an MIT-licensed TypeScript SDK for building Claude Code-style agents with stateless primitives and composable middleware.

Open-source Ruby gem giving one unified API across Anthropic, DeepSeek, Google, Mistral, Llama, and OpenAI

Mirascope is an open-source Python library that turns LLM calls, tools, and prompt versioning into plain decorated functions.

Predibase: managed fine-tuning and multi-LoRA serving for open-source LLMs, now inside Rubrik.

Open-source React framework for agent chat, generative UI, and shared state on any AG-UI backend.

Pydantic AI is the typed, open-source Python agent framework that returns Pydantic-validated objects from every run.

Open-source LLM from UC Berkeley that turns natural language into API calls and tool-using agent actions.

PrivateGPT is the open-source on-premise RAG framework for local document Q&A — 57k GitHub stars, zero cloud calls.

Open-source Java library that tokenizes text with OpenAI's BPE encodings so you can count, encode and decode locally

Python agent framework for small language models — local engines, OpenAI-compatible servers, or hosted providers, with tool-call tracing

Open-source JavaScript library that runs small LLMs like Llama 3.2 1B Instruct inside the browser via WebAssembly and WebGPU.

RubyLLM is the Ruby-native AI framework for chat, agents, tools, and RAG across 19 providers with one API.

Open Strawberry is a free, open-source chain-of-thought inspector for reading and comparing model reasoning traces.