Mastra

Free, open-source software. You pay only for the AI model you connect (or run a local one).

Code libraries for building agents yourself: you pick a model, give it tools (search, your database, your APIs) and the framework runs the reasoning loop.

Best for: Developers adding AI assistants, copilots or automated workflows to their own app.

The best-scoring models for the kind of work Mastra does. Check Mastra's docs for which models it supports.

1. 1AnthropicClaude Fable 5.157.9$10 / $50
2. 2AnthropicClaude Opus 556.5$5 / $25
3. 3xAIgrok-4.653$2 / $6
4. 4OpenAIgpt-6-astra51$10 / $50