Open-source frameworks and SDKs developers use to build their own AI agents. Compared on language, license, cost and paid hosting options.
From the 8 AI agent frameworks on Klyvoo, with prices checked on each official site.
| Agent | Best for | Starting price | Pricing model | Free trial | Standout |
|---|---|---|---|---|---|
| LangGraph | Stateful long-running agents with fine control | Free (open source) | Free; pay for model API usage and optional LangSmith hosting | Free LangSmith tier | Durable execution that recovers from failures |
| CrewAI | Role-based multi-agent teams and workflows | Free (open source) | Free; pay for model API usage and optional CrewAI AMP plan | Free AMP Basic plan | Simple role and task model for multi-agent teams |
| OpenAI Agents SDK | Lightweight multi-agent apps with handoffs | Free (open source) | Free; pay for model API usage | Small set of building blocks, easy to learn | |
| Claude Agent SDK | Agents that read files, run commands and edit code | Free SDK; pay for Claude API use | Free SDK; pay for Claude API usage | Built-in tools for files, shell and web search | |
| Microsoft Agent Framework | .NET and Python teams building production agents | Free (open source) | Free; pay for model API usage and any Azure hosting | Successor to AutoGen and Semantic Kernel, with migration guides | |
| Google Agent Development Kit (ADK) | Multi-language agents with easy Google Cloud deployment | Free (open source) | Free; pay for model API usage and any cloud hosting | Five language SDKs with a consistent API | |
| LlamaIndex | Document-heavy agents and RAG in Python | Free (open source); LlamaParse from $50/mo | Free framework; optional credit-based LlamaParse cloud plans | Free LlamaParse plan | Deep tooling for document ingestion, retrieval and RAG |
| Mastra | TypeScript developers building agents into web apps | Free (open source); Cloud Teams $250/mo | Free framework; usage-based cloud plans for hosting and observability | Free Mastra Cloud Starter | Native TypeScript with Next.js, React, Express and Hono integrations |
Prices in USD from each vendor’s official pricing page, checked October 2026. Some links may be affiliate links; that never changes our picks.
AI agent framework
Best for: stateful long-running agents with fine control
Low-level orchestration framework from LangChain for building stateful agents as graphs with durable execution.
AI agent framework
Best for: role-based multi-agent teams and workflows
Python framework for running teams of role-based AI agents as crews, with event-driven Flows for workflow control.
AI agent framework
Best for: lightweight multi-agent apps with handoffs
Lightweight open-source framework from OpenAI for multi-agent workflows with handoffs, guardrails and built-in tracing.
AI agent framework
Best for: agents that read files, run commands and edit code
Anthropic's SDK that packages Claude Code's tools, agent loop and context management as a Python or TypeScript library.
AI agent framework
Best for: .NET and Python teams building production agents
Open-source Microsoft framework for agents and multi-agent workflows, and the successor to AutoGen and Semantic Kernel.
AI agent framework
Best for: multi-language agents with easy Google Cloud deployment
Google's open-source, code-first toolkit for building, testing and deploying agents in Python, TypeScript, Go, Java and Kotlin.
AI agent framework
Best for: document-heavy agents and RAG in Python
Open-source Python toolkit for building LLM agents and event-driven workflows over your own documents and data.
AI agent framework
Best for: TypeScript developers building agents into web apps
Open-source TypeScript framework for AI agents and workflows with memory, tools, evals and a local Studio.
Every AI agent framework on this page is free to download. LangGraph, CrewAI, OpenAI Agents SDK, Microsoft Agent Framework and LlamaIndex use the MIT license. Google ADK uses Apache 2.0 and so does Mastra's core. The Claude Agent SDK is free to install but runs under Anthropic's Commercial Terms.
Your main running cost is the model. You pay your model provider for the API calls your agents make. With the Claude Agent SDK that means per-token Claude API rates billed to your API key. Microsoft Agent Framework and Google ADK only add usage-based cloud pricing if you host on Microsoft Foundry or Google Cloud.
Some frameworks sell optional hosting or tooling. LangSmith Developer is $0 per seat/month with no deployment access and LangSmith Plus is $39 per seat/month with 1 free small serverless deployment. CrewAI AMP Basic is free with 50 workflow executions a month, then Enterprise is custom pricing. Mastra Cloud has a free Starter tier and Teams at $250/month. LlamaParse is free with 10,000 credits and Starter is $50/month. The OpenAI Agents SDK has no official hosting, so you deploy it yourself.
We list every supported language and flag versions in preview or deprecated, like Go on Microsoft Agent Framework and TypeScript on LlamaIndex.
We check whether the code is under MIT, Apache 2.0 or commercial terms, since that affects how you can use it.
We note whether a framework works with many model providers or is tied to one, as the Claude Agent SDK is to Claude models.
We separate the free framework from paid hosting and model API bills so you can see what you will actually pay.
We look for memory, tracing, guardrails, human-in-the-loop steps and recovery from failures.
Every fact comes from the vendor’s official site. How we review
An AI agent framework is a code library developers use to build their own AI agents. It gives you building blocks such as the agent loop, tools, memory and handoffs between agents. LangGraph models agents as graphs with durable execution, while the OpenAI Agents SDK keeps to a small set of building blocks with tracing and guardrails built in.
Most frameworks on this page are open source. LangGraph, CrewAI, OpenAI Agents SDK, Microsoft Agent Framework and LlamaIndex are MIT licensed. Google ADK is Apache 2.0 and so is Mastra's core, though its enterprise features sit under a separate license. The Claude Agent SDK is the exception: its Python repo is MIT but use is governed by Anthropic's Commercial Terms.
Start with your language and your model. TypeScript teams lean toward Mastra, .NET teams toward Microsoft Agent Framework and Google ADK covers the most languages with Python, TypeScript, Go, Java and Kotlin. If you need fine control over long-running agents, LangGraph fits best. If you want multi-agent teams with less setup, CrewAI is easier to start with. LangChain vs LangGraph →
The frameworks are free, but you pay for the model API calls your agents make. Paid plans cover optional hosting and tooling: LangSmith Plus is $39 per seat/month, Mastra Cloud Teams is $250/month, LlamaParse Starter is $50/month and CrewAI AMP Enterprise is custom pricing. Free hosted tiers exist too, such as CrewAI AMP Basic with 50 workflow executions a month and Mastra Cloud Starter.
Side-by-side guides from the Klyvoo team on the tools in this list.
Every price on Klyvoo comes from the vendor’s official pricing page. How we review
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