Letta
★★★★★4.1AgentsFreemiumUpdated 27 Oct 2026
Stateful agents with long-term memory
Letta (formerly MemGPT) gives agents persistent memory that they manage themselves, so context survives long sessions.
letta.com
Starter prompts
Copy one into Letta and swap the {braces} for your own details.
- Research {topic} and return a short brief with sources. Ask before any irreversible action.
- Break {goal} into steps, execute them, and report what you did after each step.
- Watch {source} and tell me when {condition} changes, with a one-line summary.
Key Features
Self-editing memory
Agent curates its own recall store.
Persistent state
Sessions continue across days.
Open source
Self-host with your own models.
How to Use
- Run the server locally or use the cloud.
- Create an agent with memory blocks and tools.
- Inspect what it chose to remember.
Core Advantages
- ✓Solves long-horizon context
- ✓Open source
- ✓Research-backed
Who It's For
Agent buildersResearchersProduct teams
Pricing & Free Trial
Open source plus cloud Read from the vendor page
| Plan | Price | Notes |
|---|---|---|
| Free | $0 | |
| Pro | $20 |
Free tier: Self-host free.
Last checked 27 Oct 2026 · source page
Frequently asked questions
- What is Letta?
- Letta (formerly MemGPT) gives agents persistent memory that they manage themselves, so context survives long sessions.
- Is there a free plan for Letta?
- Self-host free.
- How much does Letta cost?
- Letta uses a open source plus cloud model. The entry paid plan is $20 (Pro).
- What can Letta do?
- Its headline capabilities: self-editing memory; persistent state; open source.
- Who is Letta for?
- It is aimed at agent builders, researchers, product teams.
Our Verdict
The most mature take on agent memory, still early for production use.
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