Mastra vs Cassidy vs Stack AI vs Sim
Side-by-side comparison of 4 verified tools.
MastraCassidyStack AISim
| Mastra A TypeScript framework for building AI agents, workflows, and applications. [#opensource](https://github.com/mastra-ai/mastra) | Cassidy AI assistants on your company data. | Stack AI No-code AI agent builder. | Sim Open-source agent workflow builder. | |
|---|---|---|---|---|
| Pricing | Freemium | Freemium | Freemium | Freemium |
| Verified free tier | — | — | — | — |
| API | — | — | ✓ | ✓ |
| Open source | — | — | — | ✓ |
| Rating | — | — | — | — |
| Freshness | 0/100 | 0/100 | 0/100 | 0/100 |
| Platforms | web | web | web, api | web, api |
| Languages | en | en | en | en |
| Categories | AI Agents | AI Agents | AI Agents | AI Agents |
| Visit | Open ↗ | Open ↗ | Open ↗ | Open ↗ |