Key features
Core capabilities each platform advertises.
Data not available
- TypeScript agent framework
- Built-in tool calling and workflows
- Sync engine for agent state
- Integration marketplace
- Production-ready agent primitives
Updated March 10, 2026
Instructor is a popular open-source library for getting structured outputs from LLMs using Pydantic models.
Mastra is a TypeScript-first agent framework for building production AI applications. It provides primitives for agents, workflows, RAG, integrations, and memory with a focus on developer experience and type safety. Mastra is designed for full-stack TypeScript developers who want to build AI features without leaving their existing tech stack.
Core capabilities each platform advertises.
What each tool does well, and the limitations to keep in mind.
Pros
Cons
Pros
Cons
Choose Instructor if you wantChoose if you want
Choose Mastra if you wantChoose if you want
Respan lets you trace LLM and agent calls across any model or framework, A/B test prompts on production traffic, and route requests across 1,000+ models through one gateway.
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