Best alternatives to Stack AI (2026)
15 verified ai agents alternatives to Stack AI, machine-checked for live status, real pricing, and genuine free tiers.
| Tool | Free tier | API | Freshness | Key difference |
|---|---|---|---|---|
| CassidyFreemium | — | — | 100 | No public API |
| SimFreemium | ✓ | ✓ | 100 | Open source |
| BhindiFreemium | ✓ | — | 100 | Verified free tier |
| Relay.appFreemium | ✓ | ✓ | 100 | Verified free tier |
| ManusFreemium | — | — | 100 | No public API |
| DelphiSubscription | — | — | 100 | No public API |
| CrewAIOpen source | — | ✓ | 100 | Open source |
| LindyFreemium | — | — | 100 | No public API |
| Relevance AIFreemium | ✓ | ✓ | 100 | Verified free tier |
| ActivepiecesOpen source | — | ✓ | 100 | Open source |
| DialogflowUsage-based | — | ✓ | 100 | Usage-based pricing |
| BardeenFreemium | ✓ | — | 100 | Verified free tier |
| PipedreamFreemium | — | ✓ | 100 | Workflow automation for devs. |
| GumloopFreemium | — | ✓ | 100 | No-code AI automation. |
| DifyOpen source | ✓ | ✓ | 100 | Open source |