Free

MemGPT

Stateful agents with persistent memory that learn continuously rather than resetting each session.

Status MemGPT is now Letta: memgpt.ai redirects to letta.com (checked 24 Sep 2026).

4.0 Very good 4.0
Directly addresses the memory limit that undermines most agents Infrastructure rather than a ready-made application
Reviewed by Challenging Voice Editorial · Updated Aug 2026 How we rate
PricingFree
Free planYes
PlatformsAPI, Web
CategoryAI Infrastructure & Agent Tooling
Visits22
Last reviewedAug 2026
UpdatedAug 2026
Ask AI about MemGPT ChatGPT Claude Perplexity

Overview

MemGPT tackles the limitation that defines most agent disappointment: a model forgets everything between sessions. Its agents are stateful, retaining what they have learned and improving over time, which is a fundamentally different architecture from stuffing history into a context window until it overflows.

The technical significance is that context windows are finite and higher-priced, so an agent that genuinely needs long-term knowledge cannot simply keep everything in context. Managing what to retain, what to retrieve and what to discard is the actual problem, and MemGPT emerged from research specifically on that.

It has a research lineage rather than being a pure product play, which shows in the framing. For developers building agents meant to work with the same user or codebase over months, persistent memory is the difference between a tool and a demo. Expect to engage with it as infrastructure rather than a finished application.

Key features

  • Stateful agents that persist memory across sessions
  • Continuous learning rather than per-session resets
  • Memory management beyond the limits of a context window
  • Research-backed approach to retention and retrieval
  • Developer-oriented infrastructure for long-running agents

Screenshots & demo

Demo video

Screenshots

MemGPT screenshot 1

Pricing

MemGPT offers a free plan, with paid upgrades for higher limits and more features.

  • Pricing modelFree
  • Starting priceFree
  • Free planYes
Visit MemGPT

Pricing is provided as a guide. Check the official site for the latest plans.

Is MemGPT expensive?

MemGPT has no advertised paid tier. Among the 62 priced tools we list in AI Infrastructure & Agent Tooling, the median entry price is $29.48 a month.

54% of AI Infrastructure & Agent Tooling tools in the directory offer a free tier, and this is one of them.

Compared against every priced listing in AI Infrastructure & Agent Tooling, recalculated as the catalogue changes. Method and the full market breakdown are in our AI tool pricing study.

Pros & cons

Pros

  • Directly addresses the memory limit that undermines most agents
  • Research foundation rather than a wrapper
  • Suits agents that must persist over months

Cons

  • Infrastructure rather than a ready-made application
  • Requires developer effort to integrate

How it compares

ToolRatingFreeFromBest known for
MemGPT (this tool)4.0YesFreeStateful agents that persist memory across sessions
Mem04.2Yes$19/moSelective memory extraction instead of full conversation-history storage
Vectorize4.1No—Per-user memory persisting across sessions
AUI4.1No—Apollo-1 foundation model

Alternatives to MemGPT

4 tools matched to MemGPT on what they do, their category and their price.

Frequently asked questions

What is MemGPT?
MemGPT tackles the limitation that defines most agent disappointment: a model forgets everything between sessions.
Is MemGPT free?
Yes, MemGPT offers a free plan. Paid plans unlock more features and higher usage limits.
What are the best MemGPT alternatives?
The closest matches in the directory are Mem0, Vectorize, and AUI, compared side by side above.

Reviews

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