# Pydantic AI vs Mastra: license, pricing and features compared (October 2026)

Canonical: https://theagenticweekly.com/compare/pydantic-ai-vs-mastra · Last verified: 2026-10-26 · Published: 2026-10-25 · Author: Agentic Weekly (operated independently from Texas, US) · Evidence: Evidence: Both tools have a Tested entry (scope on each tool page). The facts in the tables were read from each vendor's own pages and the public GitHub API on 2026-10-25 (America/Chicago) and are Reported. The What we measured section lists what we have actually run, with links to the test logs, and what we have not run yet; anything we could not confirm is marked as not captured.

**Our pick:** Pick Pydantic AI for python teams that value type safety and validation; pick Mastra for typeScript and Next.js teams building agents. No overall winner: we have not benchmarked them against each other. **Updated:** 2026-10-26 (America/Chicago).

> Pydantic AI and Mastra are both listed under Agent building. Pydantic AI is open source (MIT); Mastra is not: not a single standard license on GitHub (read the repository's license files). GitHub stars on Oct 25, 2026: Mastra 29,073 (mastra-ai/mastra) vs Pydantic AI 20,868 (pydantic/pydantic-ai). Stars measure attention, not quality. Pydantic AI is the better fit for: Python teams that value type safety and validation. Mastra is the better fit for: TypeScript and Next.js teams building agents. Facts were read from vendor and GitHub pages on Oct 25, 2026 and are Reported; what we ran ourselves is under What we measured.

## What we measured

We ran both Pydantic AI and Mastra ourselves; the table links each full test log. These are smoke tests on one CPU-only machine, not benchmarks. Each tool had its own task, so the two results are not a head-to-head. Model-driven runs used a small local Qwen2.5-3B-Instruct model.

Table: Our own tests for Pydantic AI and Mastra

| Test | Pydantic AI | Mastra |
|---|---|---|
| Hands-on test log (install and a real task) | Tested: Pydantic AI 2.61.0, Oct 25, 2026: passed. Pydantic AI 2.61.0 passed our one-tool task on a local 3B model: 3 of 3 trials; cold uv install 3.7 s. [Full test log](https://theagenticweekly.com/tests/pydantic-ai) | Tested: Mastra 0.24.9 (Node 20) / 1.79.0 (Node 24), Oct 25, 2026: passed. Mastra passed 5 of 5 on Node 20 (0.24.9) and 5 of 5 on Node 24 (1.79.0) with temperature pinned to 0, after failing 5 of 6 earlier trials at default sampling. [Full test log](https://theagenticweekly.com/tests/mastra) |

How we test and label results: [methodology](https://theagenticweekly.com/methodology#testing-rig). All test logs: [test hub](https://theagenticweekly.com/tests).

## Pydantic AI vs Mastra at a glance

Pydantic AI and Mastra are both listed under Agent building. Pydantic AI: Python agent framework built on Pydantic types, covering agents, realtime voice, image generation and embeddings. Mastra: A strong TypeScript option if you are building agents in a Node stack; read the breaking-change note on sessions before upgrading.

Table: Pydantic AI and Mastra side by side (vendor pages and GitHub, 2026-10-25)

|  | Pydantic AI | Mastra |
|---|---|---|
| Vendor | Pydantic | Mastra |
| Listed under | Agent building | Agent building |
| License | MIT | Not a single standard license on GitHub (read the repository's license files) |
| Pricing model | Free and open source | Not captured on the pages we read |
| Free tier | Free to self-host | Not captured on the pages we read |
| Paid plans | None listed for the library | Not captured on the pages we read |
| Platforms | Python | Not captured on the pages we read |
| Public repository | pydantic/pydantic-ai: 20,868 stars, last push Oct 26, 2026 UTC (GitHub API, Oct 25, 2026) | mastra-ai/mastra: 29,073 stars, last push Oct 26, 2026 UTC (GitHub API, Oct 25, 2026) |
| Latest release we saw | Oct 25, 2026 | @mastra/core@1.79.0, Oct 21, 2026 |
| Evidence | Tested (scope on its tool page) | Tested (scope on its tool page) |

## How Pydantic AI and Mastra differ

- Pydantic AI is open source (MIT); Mastra is not: not a single standard license on GitHub (read the repository's license files).
- GitHub stars on Oct 25, 2026: Mastra 29,073 (mastra-ai/mastra) vs Pydantic AI 20,868 (pydantic/pydantic-ai). Stars measure attention, not quality.
- Pydantic AI is "Free and open source"; the entry for Mastra has no pricing model we could confirm (pricing not verified).
- Latest release we saw: Pydantic AI's newest release on Oct 25, 2026; Mastra @mastra/core@1.79.0 on Oct 21, 2026 (4 days earlier).
- Pydantic AI's pricing details were captured; Mastra's were not published or could not be read, so a price comparison would be one-sided.

## Which should you pick?

- Pick Pydantic AI if: Python teams that value type safety and validation. Skip it if: you need a TypeScript framework.
- Pick Mastra if: TypeScript and Next.js teams building agents; teams that need observability and tracing out of the box. Skip it if: you work in Python.

## Strengths and limits

Table: Strengths and limits as listed on each tool page

|  | Pydantic AI | Mastra |
|---|---|---|
| Strengths | Type-safe design; MIT license | TypeScript-native; Detailed release notes with highlights; Strong observability additions in this release |
| Limits | Python only; Our test was one small task on a local 3B model; it does not show behaviour with hosted models or larger jobs | Breaking change to agent controller sessions in this release; License reported as NOASSERTION on GitHub, so check the repository's license text; Some features are experimental |

## What we did not verify

- Mastra: License terms (GitHub reports NOASSERTION).
- Output quality, speed and reliability beyond the smoke tests listed under What we measured: not compared.

## FAQ

### Is Pydantic AI or Mastra open source?

Pydantic AI: MIT. Mastra: Not a single standard license on GitHub (read the repository's license files). Licenses come from each project's GitHub repository or the vendor's own pages, read Oct 25, 2026; read the license text itself before redistributing or building a competing service.

### Does Pydantic AI or Mastra have a free plan?

Pydantic AI: Free: to self-host. Mastra: we did not capture free-tier details. Checked Oct 25, 2026; prices and limits change, so confirm on each vendor's page.

### Which was updated more recently, Pydantic AI or Mastra?

Pydantic AI's newest release we saw is (Oct 25, 2026); Mastra's is @mastra/core@1.79.0 (Oct 21, 2026). Read Oct 25, 2026 from the official release page or repository; a newer date is not a quality ranking.

### What is the main difference between Pydantic AI and Mastra?

Pydantic AI is open source (MIT); Mastra is not: not a single standard license on GitHub (read the repository's license files). GitHub stars on Oct 25, 2026: Mastra 29,073 (mastra-ai/mastra) vs Pydantic AI 20,868 (pydantic/pydantic-ai). Stars measure attention, not quality.

## Sources

- [Pydantic AI docs](https://ai.pydantic.dev/) (fetched 2026-10-25)
- [Pydantic AI repository (GitHub)](https://github.com/pydantic/pydantic-ai) (fetched 2026-10-25)
- [@mastra/core@1.79.0 release](https://github.com/mastra-ai/mastra/releases/tag/%40mastra/core%401.79.0) (fetched 2026-10-25)
- [README](https://github.com/mastra-ai/mastra) (fetched 2026-10-25)

## Related

- [Pydantic AI facts and sources](https://theagenticweekly.com/tools/pydantic-ai)
- [Mastra facts and sources](https://theagenticweekly.com/tools/mastra)
- [Alternatives to Mastra](https://theagenticweekly.com/alternatives/mastra)
- [Agent building: all tools we track](https://theagenticweekly.com/best/agent-building)
- [Pydantic AI vs LangChain](https://theagenticweekly.com/compare/pydantic-ai-vs-langchain)
- [smolagents vs Pydantic AI](https://theagenticweekly.com/compare/smolagents-vs-pydantic-ai)
- [Mastra vs Vercel AI SDK](https://theagenticweekly.com/compare/mastra-vs-vercel-ai-sdk)
- [Mastra vs LangGraph](https://theagenticweekly.com/compare/mastra-vs-langgraph)

## Changelog

- 2026-10-25: First published. Facts read from vendor pages and the GitHub API on 2026-10-25.

## How to cite

Agentic Weekly, "Pydantic AI vs Mastra: license, pricing and features compared (October 2026)", last updated 2026-10-26, https://theagenticweekly.com/compare/pydantic-ai-vs-mastra