The Stack · Alternatives

Letta (MemGPT) alternatives

The strongest open-source alternatives to Letta (MemGPT) for building AI agents — agent memory ranked by GitHub traction, each with a head-to-head.

Short answer: the closest alternative to Letta (MemGPT) is Mem0 (★ 63k), the most-starred agent memory; Zep are also strong.

Letta (MemGPT) (★ 24k) is Stateful agents with long-term memory and self-editing context, evolved from the MemGPT research. If it is not the right fit, these 2 agent memory cover the same ground — Mem0 is the most-starred option below. Or browse the best agent memory and Letta (MemGPT)'s own page.

1. Mem0

★ 63k · Python

A memory layer for AI agents — extracts, stores, and retrieves user/agent facts across sessions. Best for personalized agents.

Letta (MemGPT) vs Mem0 →

2. Zep

★ 4.8k · Go

Long-term memory store for agents with a temporal knowledge graph of facts and their validity over time. Best for temporal memory.

Letta (MemGPT) vs Zep →

Letta (MemGPT) alternatives — FAQ

What is the closest alternative to Letta (MemGPT)?

Mem0 (★ 63k) is the most-starred agent memory alternative to Letta (MemGPT). A memory layer for AI agents — extracts, stores, and retrieves user/agent facts across sessions.

What are the best alternatives to Letta (MemGPT)?

The strongest agent memory alternatives to Letta (MemGPT) are Mem0, Zep — each with a head-to-head comparison.

Is there a free alternative to Letta (MemGPT)?

Yes — the alternatives listed are open source and free to self-host; you bring your own model keys.

New agent tools & APIs, the week they ship

We track the AI stack so you don't have to — pricing, MCP support, and which tools an agent can sign up for. Free.