Alternatives to Toon

Open-source TypeScript SDK for streaming AI apps and agents across 100+ models, with built-in provider fallbacks

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

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

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

Open-source framework for adding agent chat, generative UI, and human approvals to React apps on any agent backend.

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

Open-source React toolkit for generative UI that renders your own components from natural language

Genkit is Google's open-source AI SDK for building agentic AI apps in TypeScript, Go, Python, and Dart.

Open-source Java library that puts a unified LLM and vector store API inside your JVM app

Open-source React chat UI components for building LLM chat interfaces in hours, not weeks

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

Open-source JS/TS toolkit for building multimodal LLM agents with streaming, validation, and managed memory

Rig is an open-source Rust LLM framework for shipping type-safe AI agents across 20+ providers.

Marvin is an open-source Python framework that turns LLM calls into typed functions, agents, and Pydantic-validated results.

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

A type-safe, open-source TypeScript library for orchestrating multi-step AI workflows on top of the Vercel AI SDK.

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

Open-source Java/Kotlin framework for assembling DDD-aligned SDLC LLM copilots from a five-stage pipeline.

Outlines is a Python library for structured generation that constrains LLM decoding so JSON, regex, and grammar outputs are valid every

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

Prompt engineering IDE to compose, test, and score prompts across 150+ LLMs and 15 providers.

Free browser markdown editor with Battle Mode for comparing OpenAI, Claude, and Gemini prompt outputs, client-side only.

flompt is a free visual prompt builder that compiles prompts into Claude-optimized XML blocks

Free OpenAI API examples and Python notebooks for building chat, embeddings, and RAG apps

LMQL is a programming language for LLMs that uses types, templates and constraints to make prompts modular and outputs reliable.

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

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

Hazm is an open-source Python library for Persian NLP: normalization, tokenization, tagging and dependency parsing.

Open-source Python SDK from Backblaze for chaining generative AI video, audio, and image jobs with verifiable provenance metadata on every output.

SwiftOpenAI: an MIT-licensed Swift package for calling the OpenAI API with native async/await and Combine on Apple platforms.