Eve vs Mastra: Which Agent Framework to Use?

Eve and Mastra are both TypeScript-native agent frameworks aimed at production, but they were shaped by different constraints — and that shows up in what each one bundles by default.

Mastra is deploy-agnostic and batteries-included. new Agent({ model, instructions, tools }) is one line. Tools use createTool with Zod schemas. Workflows are a first-class primitive: Workflow.step().then().branch(). RAG is built in (chunking, embedding, vector store, retrieval). Memory is short-term-per-thread and long-term-across-sessions. Mastra Studio is a local browser-based debugger for stepping through agent runs. Series A of $22M in April 2026, relicensed to Apache 2.0 the same month.

Eve is convention-driven and Vercel-runtime-coupled. An agent is a directory: agent.ts, instructions.md, tools/, skills/, subagents/, channels/, schedules/. The framework wires the files together. Under the hood it composes the Vercel Workflow SDK (durable execution), Vercel Sandbox (isolated code exec), and AI Gateway (multi-model routing). The runtime primitives are the real value — the convention is the wrapper.

The honest tradeoff: Mastra gives you agent + workflow + RAG + debugger in one install, and it runs wherever Node runs. Eve gives you agent + durable execution + sandboxed exec + provider routing, and its full power is on Vercel. If Studio + built-in RAG + deploy-anywhere is what you need, pick Mastra. If Vercel is your target and durable execution + sandboxed exec are the reasons you're reaching for a framework, pick Eve.

Pick Eve when Vercel is the deploy target and the Workflow SDK + Sandbox are the actual leverage.

• Long-running or crash-prone agents; the checkpointed workflow layer means the agent resumes cleanly after a restart.
• You're running LLM-generated code — Vercel Sandbox is one API call and you don't have to run micro-VMs yourself.
• You already ship on Vercel and want agents to inherit the same deploy story as Next.js.
• The filesystem-shaped convention (tools/, skills/, subagents/) matches how your team scales.

Pick Mastra when you want a batteries-included TypeScript agent framework you can deploy anywhere.

• Built-in RAG is genuinely useful — chunking, embedding, vector store, retrieval, all one install.
• Mastra Studio is a real productivity lever for iterating on agents locally; visual traces beat console.log.
• Deploy target is TBD or heterogeneous — Mastra runs on Node, doesn't care about the platform.
• Workflow branching (Workflow.step().then().branch()) matches your control flow needs without a graph DSL.

Both are actively evolving TypeScript-native frameworks — Mastra just took Series A, Eve is weeks old. Version churn is likely on both; pin your dependencies.

Both also add a framework layer between your code and the model API. When something goes wrong at the HTTP level, you're reading framework source before you see the actual request. That's the same tax every framework charges — and worth paying when the abstractions do real work for you, and expensive when you're using 20% of the surface.