Best 10 AI Agent Frameworks [We've Built Them for 3 Years] | Lindy
Best 10 AI Agent Frameworks [We've Built Them for 3 Years]
Written by
Marvin Aziz
Personally Tested
Growth Engineer
Marvin has tested countless AI agent frameworks including Mastra, LangChain, and CrewAI over the years. Here, he compares ease of use, integrations, and scalability for developers and business teams.
Last Updated: September 9, 2026
Table of contents
- 10 AI agent frameworks compared
- Mastra
- LangChain
- CrewAI
- OpenAI Responses API
- AutoGen
- LlamaIndex
- LangGraph
- Haystack
- FastAgency
- Rasa
Quick List of Top 10 AI Agent Frameworks
- Mastra : Best for JavaScript and TypeScript development
- LangChain : Best for custom LLM workflows
- CrewAI : Best for multi-agent orchestration
- OpenAI Responses API : Best for GPT-native applications
- AutoGen : Best for conversation-driven agents
- LlamaIndex : Best for prepackaged document agents
- LangGraph : Best for graph-based agent workflows
- Haystack : Best for retrieval and multimodal AI systems
- FastAgency : Best for high-speed inference and production scaling
- Rasa : Best for chatbots and voice assistants
Our 10 favourite AI agent frameworks compared
1. Mastra: Best AI Agent Framework for JavaScript and TypeScript development
What does it do? Mastra is an all-in-one TypeScript agent framework that helps developers quickly build, test, and deploy AI-powered applications and agents.
Who is it for? JavaScript and TypeScript developers who want to build production-ready agents, workflows, and tools within their existing codebase.
Pricing
Mastra is free and open-source under the Apache 2.0 license. Pricing for managed hosting and Studio is free with paid plans starting at $250 / month.
2. LangChain: Best AI Agent Framework for custom LLM workflows
What does it do? LangChain helps developers build, manage, and deploy AI agents that can reason, fetch data, and take action across different tools.
Who is it for? Engineers and technical teams who want deep control, full visibility, and freedom to use any AI model they like.
Pricing
LangChain has a free plan. Paid plans start at $39/seat/month.
3. CrewAI: Best AI Agent Framework for multi-agent orchestration
What does it do? CrewAI helps you build and manage teams of AI agents that can plan, reason, and collaborate to complete complex workflows.
Who is it for? Organizations that want enterprise-level control over how their AI agents work together, from setup to scaling.
Pricing
CrewAI's Basic plan is free and covers 50 workflow executions a month. Enterprise pricing is custom.
4. OpenAI Responses API: Best Framework for building GPT-native applications
What does it do? The Responses API lets you create dynamic AI assistants powered by models like GPT-5, complete with tools, structured outputs, and real-time interaction.
Who is it for? Developers and product teams who want to build GPT-based apps quickly without managing multiple endpoints or complex orchestration layers.
Pricing
Responses API is not priced separately. Tokens are billed at the chosen language model’s input and output rates.
5. AutoGen: Best AI Agent Framework for conversation-driven agents
What does it do? AutoGen lets developers build and connect multiple AI agents that can talk to each other, share context, and solve complex problems together.
Who is it for? Developers and researchers who want an open, flexible way to design multi-agent systems without being tied to any single model or vendor.
Pricing
AutoGen is open-source and free to use under the MIT license.
6. LlamaIndex: Best AI Framework offering of prepackaged agents
What does it do? LlamaIndex helps developers build AI applications faster by handling stuff like document understanding, retrieval, and workflow orchestration.
Who is it for? Developers and enterprises that rely on large amounts of unstructured data and want to turn it into something their AI agents can use.
Pricing
LlamaIndex offers a free plan. The paid plans start at $50/month (Starter) and $500/month (Professional).
7. LangGraph: Best AI Agent Framework for DAG-based agents
What does it do? LangGraph lets developers build long-running, stateful AI agents with full control over how they think, act, and recover mid-process.
Who is it for? Teams that want to design complex, custom agent workflows instead of relying on prebuilt templates.
Pricing
LangGraph has a free plan. Paid plans start at $39/seat/month.
8. Haystack: Best AI Agent Framework for RAG and multimodal AI
What does it do? Haystack lets you build production-ready AI workflows that combine large language models with external tools and data sources.
Who is it for? Developers and teams that need flexible, open-source infrastructure for building RAG, conversational, or multimodal AI applications.
Pricing
Haystack is open source and free to use; pricing for deepset Cloud (the managed platform) is available upon request.
9. FastAgency: Best Framework for high-speed inference and production scaling
What does it do? FastAgency helps developers turn their agent prototypes into production applications that run across console and web interfaces with minimal setup.
Who is it for? Freelancers, digital agencies, and small teams that want to move from Jupyter notebooks or local builds to full production systems quickly.
Pricing
Pricing is available on request.
10. Rasa: Best Agent Framework for chatbots and voice assistants
What does it do? Rasa gives developers and teams the tools to build conversational and voice AI that’s private, customizable, and ready for production.
Who is it for? Companies and developers who want full control over their assistants.
Pricing
Rasa offers a Free Developer Edition. The Growth Plan starts at $35,000/year.
What to consider while choosing an AI agent framework
Choosing the right AI agent framework depends on what you want to build and how technical your team is. Some are built for quick automation, while others offer extensive control but require more setup.
| Framework | Best for | What it does | Who it is for | Pricing |
|---|---|---|---|---|
| Mastra | JavaScript and TypeScript development | All-in-one TypeScript framework for building agents, workflows, RAG, and tools with built-in evals and observability | JavaScript and TypeScript developers building production AI apps in their existing stack | Free and open-source; Hosting/Studio free, then $250 / month |
| LangChain | Custom LLM workflows | Modular tooling for prompts, tools, memory, and deployment with deep tracing via LangSmith | Engineers who want control and visibility | Free; Plus $39/seat/month |
| CrewAI | Multi-agent orchestration | Designs and operates crews of agents with roles, memory, and AMP lifecycle management | Orgs running complex, scaled agent ops | Free; paid plans from $99/month |
| OpenAI Responses API | GPT native apps | Single endpoint for chat, tools, JSON output, and streaming on GPT-4o | Product teams building fast on OpenAI | Token based |
| AutoGen | Conversation-driven agents | Open-source framework for multi-agent dialogue, async messaging, and rich observability | Developers and researchers who like to tinker | Free and open-source |
| LlamaIndex | Prepackaged document agents | Parses, indexes, and orchestrates document workflows with LlamaCloud and Workflows | Teams with chunks of unstructured data | Free; Starter $50/month; Professional $500/mo |
| LangGraph | DAG-based agents | Low-level, stateful orchestration with checkpointing, persistence, and streaming | Teams that need durable, long-running agents | Free (MIT); hosting via LangSmith paid tiers |
| Haystack Agents | RAG and multimodal AI | Production framework for chat, retrieval, and multimodal pipelines with Studio for no-code builds | Dev teams shipping RAG and voice/image apps | Not publicly available |
| FastAgency | High-speed inference and scaling | Reuses agent logic across console and web, adds CI testing, and adapters for real deployments | Agencies and small teams moving prototypes to prod | Pricing not public |
| Rasa | Chatbots and voice assistants | Private, customizable conversational AI with Studio flow control and voice testing | Companies that need control and compliance | Free for Developer; Growth from $35,000/yr |
FAQs
1. What are the best virtual machine options for running AI agents that generate and execute code with minimal latency?
The best virtual machine options for running AI agents that generate and execute code with minimal latency are AWS EC2 G5 instances, Google Cloud A2, and Azure NV-series.
2. What voice engines integrate best with agent frameworks?
The voice engines that integrate best with AI agent frameworks are Deepgram, Cartesia, and ElevenLabs.
3. What is the best low-latency LLM platform for AI agent orchestration?
The best low-latency LLM platform for AI agent orchestration is OpenAI’s GPT-4o.
4. What are the top AI agent frameworks in 2026?
The top AI agent frameworks in 2026 are Mastra, LangChain, CrewAI, OpenAI Responses API, AutoGen, LlamaIndex, LangGraph, Haystack Agents, FastAgency, and Rasa.
5. How can I choose a scalable AI agent framework for complex workflow management?
To choose a scalable AI agent framework for complex workflow management, focus on durability, state management, and multi-agent support.