- fix: workflows update
- fix(security): use JSON instead of pickle for sandbox->server tool result transport
Letta by Letta
Pulse Score
30 / 100
Rank #100 of 157
Downloads, last 7 days
12.4K
up 27.5% vs previous week
Downloads, last 30 days
29.4K
— vs previous 30 days
GitHub stars
25K
about +12 a day
Latest release
0.16.8
4mo ago
Price
Free (OSS)
checked Oct 5, 2026
Overview
A platform for stateful agents with long-term memory that persists across sessions. Formerly known as MemGPT.
Letta was downloaded 12.4K times from PyPI in the week ending Oct 4, 2026, up 27.5% on the week before. Its download count moved to a different level overnight on Aug 25, 2026. A jump like that comes from automated installs switching on or off or from a change in how the registry counts, so growth rates across that date are not shown. The GitHub repository has 25K stars, 444 of them added in the last 30 days. The latest stable release is 0.16.8, published May 14, 2026. It was mentioned in 2 Hacker News posts and comments over the last 30 days.
Letta usage and attention over time
Download the raw daily series: letta.csv
Install Letta
| PyPI | pip install letta |
|---|
These commands use the packages tracked on this page. The vendor may recommend a different installer; see the official documentation.
Key facts
| Maker | Letta |
|---|---|
| Type | Stateful agent platform |
| License | Apache-2.0 |
| Interfaces | Python library, REST API |
Pricing
The Letta server is open source and free to self-host. The company also runs a paid hosted service.
Source: official pricing page, checked Oct 5, 2026. Prices change often; confirm before you buy.
Pulse Score breakdown
Adoption24
Community58
Attention0
Momentum51
Each component is scored 0 to 100 from public signals; a dash means no data for it. Methodology.
What changed: recent Letta releases
- Block limits are no longer enforced -- block limit validation has been deprecated and removed from the git memory sync path (#9977, #9983). Blocks can now grow freely. If you were relying on…
- Global context window default raised from 32k to 128k (#9993) -- self-hosted servers no longer default to 32k for unknown models
- Context window preserved on conversation model override (LET-7991, #9986) -- the bug where non-default conversations fell back to 32k is fixed
- Compaction overflow fixes (#9897) -- addresses the double-compaction and runaway compaction loops
- Compaction model resets on agent model change (#10031) -- switching your agent's model no longer leaves the old summarizer model behind
- Summarizer prompt improved (#10314) -- now remembers plan files, GitHub PRs, and other structured content during summarization
- Expanded Conversations API support for default conversation / agent-direct mode.
- New conversations now initialize with a compiled system message at creation time.
- Fixed modelsettings.maxoutputtokens default behavior so it does not silently override existing maxtokens unless explicitly set.
- Added support for conversationid="default" + agentid across conversation endpoints (send/list/cancel/compact/stream retrieve).
- Kept backwards compatibility for conversationid=agent- (deprecated path).
- Added lock-key handling in agent-direct flows to avoid concurrent execution conflicts.
- chore: bump version 0.16.5
- fix: update gh templates
- chore: release 0.16.3
- chore: bump v0.16.4
- docs: update README.md
- Update contributing.md with corrected local setup steps
- chore: bump version 0.16.2
- @neversettle17-101 made their first contribution in
Letta alternatives
| # | Agent | Pulse | Downloads 7d | 7d | 30d | VS Code installs | Stars | Latest release | Price | Last 90 days | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 4 |
LangChainLangChain |
77 | 44.3M | up 1.9% | down 22.0% | — | 147K+45/day | 1.4.38d ago | Free (OSS) | ||
| 10 |
LangGraphLangChain |
69 | 16.1M | up 11.4% | down 21.8% | — | 42.7K+48/day | 1.2.13yesterday | Free (OSS) | ||
| 11 |
AI SDKVercel |
67 | 34.5M | up 13.5% | up 20.9% | — | 27.1K+18/day | 6.0.301yesterday | Free (OSS) | ||
| 13 | 63 | 8.7M | up 0.6% | up 2.0% | — | 8,679+23/day | 1.58.0yesterday | Free (OSS) | |||
| 17 |
Claude Agent SDKAnthropic |
59 | 21.5M | up 14.6% | up 0.6% | — | 8,219+5/day | 0.2.1636d ago | Free (OSS) | ||
| 21 |
MastraMastra |
58 | 2.2M | up 11.1% | up 19.1% | — | 28.6K+27/day | 1.74.0yesterday | Free (OSS) | ||
| No agents match that filter. | |||||||||||
Letta FAQ
How much does Letta cost?
The Letta server is open source and free to self-host. The company also runs a paid hosted service.
Is Letta open source?
Yes. Letta is open source, released under the Apache-2.0 license.
How popular is Letta?
Letta was downloaded 12.4K times from PyPI in the week ending Oct 4, 2026, up 27.5% on the week before. Its download count moved to a different level overnight on Aug 25, 2026. A jump like that comes from automated installs switching on or off or from a change in how the registry counts, so growth rates across that date are not shown. The GitHub repository has 25K stars, 444 of them added in the last 30 days.
What is the latest version of Letta?
The latest stable release we track is 0.16.8, published on May 14, 2026.
What are the alternatives to Letta?
The closest alternatives in the same category by Pulse Score are LangChain, LangGraph, AI SDK, Strands Agents.
Where these numbers come from
PyPI: letta. GitHub: letta-ai/letta. See data sources for how each one is collected.