Letta vs Mastra
Side-by-side comparison of two agent options that often come up together when people are choosing between self-hosted frameworks, managed assistants, and extensible AI tooling.
Open source22k stars
Letta
Platform for building stateful agents with advanced memory persistence
Open source23k stars
Mastra
TypeScript-first agent framework with observational memory and workflow orchestration
Category
Letta
Mastra
Tagline
Platform for building stateful agents with advanced memory persistence
TypeScript-first agent framework with observational memory and workflow orchestration
Deployment
Self-Hosted
Self-Hosted
Pricing
Usually affordable for individuals or small teams, with some recurring model or hosting costs.
Free to use, with optional model or infrastructure costs if you self-host.
Channels
Telegram, Slack, Discord, WhatsApp, Signal
Web, CLI
Open source
Yes
Yes
Privacy
Good privacy posture for most teams, especially when self-hosted or carefully configured.
Good privacy posture for most teams, especially when self-hosted or carefully configured.
Letta pros
- Open source with transparent code and flexible deployment options.
- Strong privacy story for users who care where data runs.
- Good memory and persistence support for ongoing conversations or tasks.
Mastra pros
- TypeScript-first — rare in the agent framework space (most are Python)
- Observational Memory — automatically tracks and surfaces agent reasoning patterns
- From the Gatsby team — proven track record building developer-facing OSS
Letta cons
- Lower autonomy — designed more as a platform than an out-of-box assistant
- Setup requires understanding memory architecture concepts
- Python-only — no native TypeScript/JavaScript implementation
Mastra cons
- TypeScript-only — not suitable for Python-heavy stacks
- Younger ecosystem compared to LangChain or CrewAI
- Primarily a development framework — not a ready-to-use personal assistant
Letta gotchas
- You should expect ongoing hosting, uptime, and secret-management work if you deploy it for real users.
- Recurring subscription or model spend can matter more than the headline feature list.
Mastra gotchas
- You should expect ongoing hosting, uptime, and secret-management work if you deploy it for real users.
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