
CrewAI
Multi-agent automation framework & studio to build and run AI crews
Discover top open-source software, updated regularly with real-world adoption signals.

Build stateful AI agents with persistent, self‑editing memory
Letta lets developers create AI agents that retain and edit memory over time, offering Python/TypeScript SDKs, a no‑code UI, desktop client, and cloud service for rapid deployment.

Letta is a platform for building stateful AI agents that maintain and modify their own memory across interactions. By leveraging a memory hierarchy of in‑context and out‑of‑context blocks, agents can edit, delete, or search their knowledge base using built‑in tools such as web search and code execution.
Developers can interact with Letta through Python or TypeScript SDKs, a no‑code Agent Development Environment (ADE), a fully‑local desktop client for macOS and Windows, or the Letta Cloud service. Self‑hosting is also supported by running a local server and pointing the SDK to a custom base URL, giving full control over data privacy and infrastructure.
The platform enables multi‑agent architectures with shared memory blocks, allowing agents to collaborate on a common knowledge store. Sleep‑time agents run in the background, continuously updating memory without user prompts, effectively acting as an agent’s subconscious.
When teams consider Letta, these hosted platforms usually appear on the same shortlist.
Looking for a hosted option? These are the services engineering teams benchmark against before choosing open source.
Customer Support Agent with Personalized History
Remembers each user's preferences and past tickets, providing tailored responses and reducing repeat inquiries.
Project Management Assistant with Shared Organization Memory
Multiple agents access a common memory block to coordinate tasks, deadlines, and resources across teams.
Personal Productivity Bot with Sleep‑Time Processing
Background sleep‑time agent updates the user's knowledge base overnight, enabling proactive suggestions each morning.
Research Knowledge Curator that Self‑Improves
Agent continuously ingests new papers via web search tool, updates its memory, and offers up‑to‑date summaries.
Sign up on Letta Cloud; after verification you can generate an API key from the dashboard.
Letta supports any model accessible via its API, such as OpenAI GPT‑4.x, GPT‑3.5, and Anthropic Claude models.
Yes, by self‑hosting the Letta server and pointing the SDK to your local base URL.
A memory block that multiple agents can attach to, allowing them to read and write common information.
Letta Cloud offers a free trial with limited usage; self‑hosted deployments depend on your own resources.
Project at a glance
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