Letta vs 
Hermes Agent
Letta vs Hermes Agent compared for 2026 — features, license, ease of use, performance and which one to choose. Stateful agents with long-term memory vs An agent that keeps what it learns from you.
Updated regularly · curated by olud.ai
Letta vs Hermes Agent at a glance
| Spec | Letta | Hermes Agent |
|---|---|---|
| Category | AI agent framework | AI agent framework |
| Type | Agent runtime (memory) | Autonomous agent (Python) |
| License | Apache-2.0 | MIT |
| Runs locally | Self-hosted | Yes |
| Primary language | Python | Python |
| Ease of use | Advanced | Intermediate |
| Best for | agents that remember across sessions | developers building an agent meant to be lived with, not called once |
| GitHub stars | 24.5k | 239k |
How Letta and Hermes Agent score
| Criterion | Letta | Hermes Agent |
|---|---|---|
| Popularity | 3.5 | 5.0 |
| Maintenance | 5.0 | 5.0 |
| Ease of use | 2.5 | 3.5 |
| Privacy | 4.5 | 5.0 |
| 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
Hermes Agent
Hermes Agent from Nous Research is an autonomous agent built to accumulate context over time rather than start from zero at each session, so its usefulness compounds with use.
- Carries context forward between sessions
- MIT licence with no usage restriction
- Backed by a research lab with a track record on open weights
Key differences
Letta is agent runtime (memory), while Hermes Agent is autonomous agent (Python). Their licenses differ (Apache-2.0 vs MIT), which matters if you ship a commercial product. Letta leans more advanced-friendly, whereas Hermes Agent is more suited to intermediate users. They also differ in how they run (Self-hosted vs Yes). In short, Letta fits agents that remember across sessions, and Hermes Agent fits developers building an agent meant to be lived with, not called once.
Which should you choose?
Choose Letta for agents that remember across sessions. Choose Hermes Agent for developers building an agent meant to be lived with, not called once.
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 Hermes Agent easier to use?
Hermes Agent is generally the easier of the two to get started with, while Letta rewards more setup with more control.
Are Letta and Hermes Agent free?
Letta is free and open source (Apache-2.0), and Hermes Agent is free and open source (MIT). Neither charges for the core software.
Can I run Letta and Hermes Agent locally?
Letta: self-hosted · Hermes Agent: yes. Both can be used without sending your data to a third-party cloud where their setup allows.
Letta vs Hermes Agent — which should I pick in 2026?
Choose Letta for agents that remember across sessions. Choose Hermes Agent for developers building an agent meant to be lived with, not called once.
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