# The Best AI Agent Frameworks (2026)

By Steven Van · 2026-10-06

Browser Use compares Mastra, LangGraph, CrewAI and three other open-source frameworks by language, workflow control and use case.

[Browser Use](<https://creatorstoolbox.com/resources/browser-use>) has published [a comparison of six open-source AI agent frameworks](<https://browser-use.com/posts/best-ai-agent-frameworks>): Mastra, LangGraph, OpenAI Agents SDK, CrewAI, Pydantic AI and Vercel AI SDK. The article sorts them by language, workflow control, tools and use case.

## Which framework for which job

- **Mastra:** TypeScript agents and workflows. It combines agent execution, tool integrations, memory, document retrieval and workflows, and includes Mastra Studio, a local interface for testing agents and inspecting runs.

- **LangGraph:** branching, stateful workflows in Python or TypeScript. With persistent storage configured, an agent can pause for approval and resume. It works independently of LangChain.

- **OpenAI Agents SDK:** agent delegation and tracing in Python or TypeScript. It also supports non-OpenAI models, though available features depend on the provider integration and language SDK.

- **CrewAI:** teams of specialist agents, with Flows controlling the surrounding process.

- **Pydantic AI:** typed, validated Python outputs.

- **Vercel AI SDK:** agents and streaming web interfaces, and a starting point when model calls and streaming interfaces are the main concern.

## How the article suggests choosing

It names four factors: application fit, workflow control, developer experience and cost. On cost, it notes that a free framework still incurs charges for models, tools and infrastructure. Repeated tool calls, retries and multiple agents can raise the price of a single task, and managed hosting or observability services add to the total.

## Background it covers

The piece also defines an agent framework and walks through the tool-calling loop. It separates agents, where the model chooses the next step, from workflows, where steps are defined in code, and says the two can be combined. It adds that direct API code may be enough for an application with only a few model calls and tools.

![Browser Use](<https://www.google.com/s2/favicons?domain=browser-use.com&sz=128>)

Browser Use

Open-source browser automation platform for AI agents — let LLMs drive a real browser to research, fill forms, scrape, and complete multi-step tasks.

[View Browser Use →](<https://creatorstoolbox.com/resources/browser-use>)

Sources

[Original source](<https://browser-use.com/posts/best-ai-agent-frameworks>)

[Read The Best AI Agent Frameworks (2026) on Creators Toolbox](<https://creatorstoolbox.com/blog/browser-use-the-best-ai-agent-frameworks-2026>)

---
Canonical source: https://creatorstoolbox.com/blog/browser-use-the-best-ai-agent-frameworks-2026