Letta vs Zep
A side-by-side comparison of Letta and Zep, two Memory tools, drawn from Ignaite's continuously-verified listings.
Compared from listings verified as of
At a glance
| Attribute | Letta | Zep |
|---|---|---|
| Category | Memory | Memory |
| Pricing | FREEMIUM | FREEMIUM |
| License (differs) | Open core | Proprietary |
| Deployment (differs) | Hybrid | Cloud |
| Platforms (differs) | API, CLI, macOS, Windows, Linux | API |
| Model support (differs) | BYO key / model | Multi-model |
| Vendor (differs) | Letta | Zep |
| Capabilities (differs) |
|
|
The honest brief
Letta
The productized MemGPT successor — agents edit their own memory blocks (memory-as-OS) to manage a finite context window.
- Self-editing agent memory
- Open source, model-agnostic
- REST APIs + multi-language SDKs
- Reference architecture for memory
- Developer-focused, not no-code
- Memory model has a learning curve
- Younger, evolving framework
Zep
Stores a temporal knowledge graph (via OSS Graphiti) that versions how facts change over time, not flat snapshots.
- Open-source Graphiti engine (Apache-2.0)
- Managed Zep Cloud option
- Pulls in chat + business data
- Long-term context for agents
- Graph approach has learning curve
- Cloud is credit-based pricing
- Heavier than simple vector memory
- Newer ecosystem
When to pick which
Across the signals we compare, Letta and Zep differ on license, deployment, platforms, and model support:
- License
- Open core · Proprietary
- Deployment
- Hybrid · Cloud
- Platforms
- API, CLI, macOS, Windows, Linux · API
- Model support
- BYO key / model · Multi-model
Their capability lists differ in recorded depth — compare the full lists above before deciding.