Ax

Ax is an open-source library for building AI features and agents with DSPy-style programming across six programming languages.

PricingFree
Free planYes
UrduLimited / no

Best for: Developers adding AI features to apps

Visit Ax

Ax lets developers add AI features and agents to their apps. You define inputs and outputs, then improve results using examples and evaluations, following a DSPy-style approach instead of hand-tuning prompts.

It includes RLM-powered agents that work through data and tools using code, along with validated outputs. Native libraries are available for TypeScript, Python, Java, C++, Go and Rust. It is free and open source.

Key features

  • DSPy-style programming
  • RLM agents
  • Validated outputs
  • Six language libraries

Prices and features change often; check the official website for the latest plans. Last updated September 24, 2026.

Alternatives

Keyapi.ai
Freemium · free plan
ClearPact
Paid
AIQualityHQ
Free · free plan
a0.dev
Freemium · free plan
AI SDK
Free · free plan