Letta vs 
Mem0
Letta vs Mem0 compared for 2026 — features, license, ease of use, performance and which one to choose. Stateful agents with long-term memory vs Long-term memory for AI agents.
Updated regularly · curated by OpenSourceAI.tech
Letta vs Mem0 at a glance
| Spec | Letta | Mem0 |
|---|---|---|
| Category | AI agent framework | AI agent framework |
| Type | Agent runtime (memory) | Agent memory layer |
| License | Apache-2.0 | Apache-2.0 |
| Runs locally | Self-hosted | Self-hosted |
| Primary language | Python | Python |
| Ease of use | Advanced | Intermediate |
| Best for | agents that remember across sessions | developers adding persistent memory to agents |
| GitHub stars | 23.8k | 60.7k |
How Letta and Mem0 score
| Criterion | Letta | Mem0 |
|---|---|---|
| Popularity | 3.5 | 4.5 |
| Maintenance | 5.0 | 5.0 |
| Ease of use | 2.5 | 3.5 |
| Privacy | 4.5 | 4.5 |
| License freedom | 5.0 | 5.0 |
Scores are computed automatically from public signals — GitHub stars (popularity), recent commit activity (maintenance), license type (freedom), local-first design (privacy) and onboarding complexity (ease of use). Indicative, not a verdict.
What each one is
Letta
Letta (formerly MemGPT) is a framework and server for building stateful agents with long-term memory that persists across sessions, with a visual agent editor.
- Persistent long-term agent memory
- Server with REST API and visual editor
- Model-agnostic and self-hostable
Mem0
Mem0 is a memory layer that gives agents and assistants persistent, personalized memory across sessions, with APIs to store, search and consolidate memories.
- Persistent, personalized agent memory
- Automatic memory extraction and consolidation
- Self-hosted or managed, framework-agnostic
Key differences
Letta is agent runtime (memory), while Mem0 is agent memory layer. Letta leans more advanced-friendly, whereas Mem0 is more suited to intermediate users. In short, Letta fits agents that remember across sessions, and Mem0 fits developers adding persistent memory to agents.
Which should you choose?
Choose Letta for agents that remember across sessions. Choose Mem0 for developers adding persistent memory to agents.
There is rarely one winner — many setups use both. The right pick depends on your hardware, your team's skills, and whether you value simplicity or control.
Frequently asked questions
Is Letta or Mem0 easier to use?
Mem0 is generally the easier of the two to get started with, while Letta rewards more setup with more control.
Are Letta and Mem0 free?
Letta is free and open source (Apache-2.0), and Mem0 is free and open source (Apache-2.0). Neither charges for the core software.
Can I run Letta and Mem0 locally?
Letta: self-hosted · Mem0: self-hosted. Both can be used without sending your data to a third-party cloud where their setup allows.
Letta vs Mem0 — which should I pick in 2026?
Choose Letta for agents that remember across sessions. Choose Mem0 for developers adding persistent memory to agents.
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