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Cognee vs Letta

A side-by-side comparison of Cognee and Letta, two Memory tools, drawn from Ignaite's continuously-verified listings.

Compared from listings verified as of

Cognee

Memory

Open-source memory for AI agents.

View Cognee

Letta

Memory

Stateful agents with structured memory. Successor to MemGPT.

View Letta

At a glance

Feature comparison of Cognee and Letta
AttributeCogneeLetta
CategoryMemoryMemory
PricingFREEMIUMFREEMIUM
LicenseOpen coreOpen core
DeploymentHybridHybrid
Platforms (differs)APIAPI, CLI, macOS, Windows, Linux
Model supportBYO key / modelBYO key / model
Vendor (differs)CogneeLetta

The honest brief

Cognee

Builds an LLM-derived knowledge graph alongside embeddings, so recall follows relationships, not just vector similarity.

  • Self-hostable Python SDK
  • Recall follows concept relationships
  • Bring your own LLM/embedding provider
  • Newer, smaller ecosystem
  • Cognify pipeline adds LLM cost
  • Self-host setup overhead

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