Alternatives to Kiln

Local, MIT-licensed token and cost observability for AI coding agents — no SDK, no signup, nothing leaves your machine.

A local MCP context layer that filters what your coding agent sees, cutting token use before requests leave your machine.

Prompt engineering IDE for building, testing, and optimizing prompts across 150+ LLMs from 15 providers.

Open-source TypeScript framework for building durable AI agents and workflows, with a hosted platform for observability and cloud deployment.

Open-source TypeScript toolkit for building AI apps and agents across 100+ models with streaming, tools, and fallbacks

Open-source Python library that constrains LLM decoding with finite-state machines so Pydantic, JSON Schema, regex, and grammar outputs come out valid every

BAML is a type-safe programming language for building AI agents and structured LLM output that compiles instead of guessing.

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

AppWorld is a simulated-world benchmark for evaluating AI coding agents across 9 apps and 457 APIs.

Rig is a free, MIT-licensed Rust library for building LLM apps and agents behind one unified API across 20+ model providers.

Google's open-source framework for building AI-powered and agentic apps in TypeScript, Go, Python, and Dart.

A Rust library for building fast, streaming LLM pipelines — indexing, retrieval, and autonomous agents.

Build AI agents on small language models — locally, on your own server, or through 10 hosted providers.

Open Harness is an open-source TypeScript SDK for building Claude Code-style agent harnesses with stateless primitives and composable middleware.

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

Open source Python and TypeScript SDKs for building production AI agent harnesses you control end to end.

Marvin is an open-source Python framework that turns ordinary functions into AI-powered tools using decorators like @ai_fn and @ai_classifier.

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

Agent and LLM observability from the LangChain team: trace, monitor, and evaluate agents in production, cloud, BYOC, or self-hosted.

Arena AI is a free LLM leaderboard where live head-to-head battles and community votes rank chat models, coding agents, and fullstack code.

CopilotKit is the open-source React framework for adding agent chat, generative UI, and shared state to any AG-UI backend.

Agent evaluation, simulation and tracing platform that helps you catch hallucinations before customers do

Honeycomb's natural-language query layer that turns plain-English questions into HQL against your live telemetry.

Open-source Python library for constraining LLM output with regex, context-free grammars, and inline control flow — archived since October 2023.

Pydantic AI is a typed Python agent SDK: define a model string and an output type, get validated structured results every run.

Outlier AI pays subject-matter experts to train AI models remotely on flexible, project-based work with weekly pay.

OpenAI Cookbook is a free, MIT-licensed GitHub repository of example code and guides for working with the OpenAI API.

Open-source benchmark that scores AI agents on real, multi-step software-company work tasks.

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

OpenUI is an open-source framework that lets AI agents stream interactive UI from your own React, Vue, Svelte or React Native components instead of raw JSON.