agentlib vs Mastra — Dart mobile-native vs TypeScript backend
Side-by-side: agentlib (Dart, mobile-native, on-device + cloud) vs Mastra (TypeScript, server-side / edge, multi-provider). Different runtimes, complementary roles.
Mastra is the strongest TypeScript-first agent framework today. agentlib is the strongest Dart-first mobile agent framework. The decision is mostly about which runtime your agent code lives in.
Runtime
- Mastra: TypeScript. Node, Bun, Deno, Cloudflare Workers, Vercel. Server-side or edge.
- agentlib: Dart. Inside a Flutter app — iOS, Android, macOS.
You can’t run Mastra natively inside an iOS app sandbox. You can’t run agentlib on a Cloudflare Worker. Pick by where the agent code needs to ship.
Primitive overlap
Both ship strong agent loops, multi-provider model routing, MCP support, and workflow primitives. The shapes are different but the ambitions are similar.
| Primitive | Mastra | agentlib |
|---|---|---|
| Multi-provider models | ✓ (cloud) | ✓ (cloud + on-device) |
| Subagents | agent-as-tool | sync / parallel / background |
| Handoffs | ✓ | ✓ (1.1.0+) |
| Workflows | ✓ (steps) | ✓ (subagent composition) |
| Snapshots | partial | public API, SQLite |
| Hooks | some | 21 |
| MCP | HTTP | HTTP + WebSocket |
| RAG | first-class | bring your own retriever |
| Tool surface | JSON-RPC | JSON-RPC + Sh mini-shell |
| Lifecycle | suspend / resume | suspend / resume + push-resume + battery / network |
| Runtime | TS backend / edge | Dart Flutter app |
Mastra’s RAG story is more developed; agentlib treats retrieval as a tool you bring. agentlib’s mobile-lifecycle story doesn’t exist in Mastra (and doesn’t need to, for the backend target).
Combining them
Backend + mobile is a clean split. Mastra orchestrates server-side workflows and serves an HTTP API or an MCP server. agentlib’s Flutter agent calls into it. Some teams put the heavy reasoning behind a Mastra service and use agentlib for everything device-side.
Bottom line
For TypeScript backends and edge deployments, Mastra is excellent. For mobile apps, agentlib is the native pick. For products that span both, run them together — same protocols, complementary scopes.
- Your agent runs inside a Flutter, iOS, or Android app.
- You need on-device models or sandbox-safe execution.
- You want native Dart APIs and pub.dev distribution.
- You need lifecycle hooks (suspend / resume / low battery).
- You want a Unix-shell-shaped tool surface (Sh).
- Your agent runs on a TypeScript backend (Node, Bun, Deno).
- You're deploying to edge runtimes (Cloudflare Workers, Vercel).
- You want a TypeScript-first agent framework with workflows and RAG.
- You need a mature TypeScript MCP ecosystem.
FAQ
- Can I use Mastra on the backend and agentlib on the device?
- Yes, and this is a sensible split. Mastra handles backend orchestration, workflows, RAG; agentlib handles the device-side agent (UI orchestration, on-device classification, offline fallback). They interoperate over MCP or HTTPS.