AI agent builders
Mastra: review, pricing, data and alternatives
Mastra lets developers create agents connected to models and tools. It supports multistep workflows, conversation memory, agent testing and trace inspection, and deployment on a hosted platform. A free tier exists; the first paid plan costs $250 per month. Access and transparency score: 73/100, #5 of 20 in its category.
What is Mastra?
Mastra lets developers create agents connected to models and tools. It supports multistep workflows, conversation memory, agent testing and trace inspection, and deployment on a hosted platform.
According to its documentation, Mastra lets you:
- create agents connected to models and tools
- build multistep workflows
- retain conversation memory
- test agents and inspect their traces
- deploy agents on a hosted platform
We file it under AI agent builders, the category of tools to build your own AI agents, and it also overlaps with lLMOps and observability and developer tools. The category lists 20 verified tools on this site.
The publisher is Kepler Software Inc., based in United States. The service launched in 2024.
Who is it for?
It is mostly useful to these profiles: developers. The need it covers is simple to state: build your own AI agents.
Mastra is a good candidate if:
- you want to try before paying
- you plan to connect it to your tools or automations through its API
- you want to read the code or host it yourself
The best test is a concrete case from your daily work: if the tool does not beat your current method within a week, move on to an alternative.
How much does Mastra cost?
Pricing model: open source (public code). A free plan is offered, usually limited in volume or features.
The first paid plan costs $250 per month (Teams on Mastra Platform; the free Starter plan also includes usage-based billing for overages), according to the pricing page, checked on October 24, 2026.
Per month, that is more expensive than the category median ($20 per month, based on tools with a published price).
To estimate what the same work would cost done directly with an AI model, use our API price calculator. Prices change often: always check the official site before subscribing.
Data and privacy
According to its privacy policy, data is processed in several regions depending on the plan.
No export feature is documented: keep a copy of your content elsewhere.
Three habits apply to every AI tool:
- turn off the use of your content for training if the option exists
- use a work account separate from your personal account
- review everything the tool produces before publishing or sending it
Platforms, languages and API
Mastra runs on: web browser and API.
Interface languages: English.
A public API lets you call it from your own programs or an automation tool, and plug it into an AI agent.
The source code is public: mastra-aimastra-ai/mastra.
How we scored it
Our 73/100 score does not judge output quality: it measures what can be publicly verified about access to the tool, its openness and how far the publisher can be trusted.
| Criterion | Points | What counts |
|---|---|---|
| Access | 25/30 | free tier, published price, French interface |
| Openness | 20/30 | API, data export, open code |
| Trust | 28/40 | identified publisher, declared hosting, age, presence in reference lists |
The full calculation is explained on our method page.
Comparison with alternatives
Mastra against other tools in the aI agent builders category:
| Tool | Free | Entry price | API | Score |
|---|---|---|---|---|
| Mastra | Yes | $250 per month | Yes | 73 |
| Dify | Yes | $590 per year | Yes | 81 |
| Agenta | Yes | $29 per month | Yes | 78 |
| AutoGen | Yes | not published | Yes | 78 |
| Hermes Agent | Yes | $20 per month | Yes | 73 |
| OpenClaw | Yes | not published | – | 71 |
| Botpress | Yes | $150 per month | Yes | 68 |
| MindStudio | Yes | $20 per month | Yes | 68 |
Verdict
Mastra is a decent option; compare its price and terms with the category leaders.
Strengths
- Free tier to try it
- Public API
- Public source code
Limitations
- More expensive than its category median
- Data export not documented
Avoid if…
- You need to easily retrieve your full history
Alternatives
Categories and jobs
Learn more
Frequently asked questions
Is Mastra free?
Yes, a free plan exists, with usage limits. The first paid plan costs $250 per month.
Where is Mastra data stored?
According to the publisher, in several regions depending on the plan.
Does Mastra have an API?
Yes, a public API is documented.
What are the alternatives to Mastra?
In the same category: Dify, Agenta, AutoGen, and Hermes Agent.
Mastra or Dify: which one to choose?
Mastra starts at $250 per month, Dify at $590 per year and our score is 73/100 for Mastra and 81/100 for Dify. Try both on the same task before paying.
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Neutrality. No affiliate links. No vendor pays to be reviewed, rated or ranked. Reviews are directed by François Chollet, neutral and factual, and every data point is dated and sourced. How we score