Letta: Open Source Alternative to LangChain

Letta (formerly MemGPT) is a framework for building stateful AI agents with 23k+ GitHub stars — a LangChain alternative focused on persistent memory and self-improving agents.

Compare Letta with LlamaIndex before you choose your stack.

Key features

Memory management

• Persistent memory across conversations and sessions
• Editable memory blocks for agent state
• Automatic memory consolidation and summarization
• Multi-tier memory (core, archival, recall)
• Memory search and retrieval

Agent capabilities

• Self-improving agents that learn from interactions
• Multi-step reasoning and planning
• Tool use and function calling
• Multi-agent orchestration
• Human-in-the-loop workflows

Developer experience

• Python SDK with type hints
• REST API for language-agnostic access
• Pre-built agent templates
• Integration with OpenAI, Anthropic, and local models
• Web UI for agent management

Production features

• Conversation persistence and history
• Agent versioning and rollback
• Usage analytics and cost tracking
• Role-based access control
• SSO and enterprise authentication

Letta vs LangChain

	Letta	LangChain
License	Apache-2.0 (open source)	Proprietary
Models	Bring your own keys / local models	Vendor-locked models
Deployment	Self-hosted or cloud	SaaS only
Privacy	Data stays on your infrastructure	Processed by vendor
Cost	Free software + API usage	Subscription pricing

Choose Letta if you want open-source code, self-hosting options, and full control over your data and deployment.

Choose LangChain if you prefer a managed proprietary product with vendor support and minimal setup.

Browse more open-source alternatives to LangChain, or explore other tools in Developer Tools.

At a glance

License	Apache-2.0
Stack	Python, TypeScript, PostgreSQL
Self-hosted	Yes — Letta OSS
Cloud	letta.com (managed)
Memory	Persistent, multi-tier

Self-hosting

pip install letta

Letta can be embedded in your application or run as a standalone server. The cloud version provides managed infrastructure and team features.

FAQ

Is Letta a free alternative to LangChain?

Yes. Letta is open source under Apache-2.0. You can self-host it at no software cost — you only pay for infrastructure or optional managed services.

How does Letta compare to LangChain?

Letta gives you source code access, self-hosting, and data ownership. LangChain is a proprietary product focused on managed convenience. See the comparison table above for a side-by-side breakdown.

Can I self-host Letta?

Yes. Letta supports self-hosted deployment, which is a core reason teams choose it over LangChain. Check the Getting started or Self-hosting section for install commands.

Is Letta suitable for production?

Letta is actively maintained with a strong open-source community. Many teams run it in production as a Developer Tools alternative to LangChain. Review the At a glance table for license and stack details.

What are alternatives to Letta and LangChain?

Browse alternatives to LangChain for more open-source options, including tools compared to LlamaIndex. Explore the full Developer Tools category for related projects.