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Letta vs Mem0: license, pricing and features compared (October 2026)

Letta and Mem0 are both listed under Agent building. GitHub stars on Oct 25, 2026: Mem0 67,804 (mem0ai/mem0) vs Letta 25,254 (letta-ai/letta). Stars measure attention, not quality. Latest release we saw: Mem0 Python SDK v2.2.1 on Sep 25, 2026; Letta v0.16.8 on May 14, 2026 (134 days earlier). Letta is the better fit for: agents that must remember across sessions. Mem0 is the better fit for: apps that need long-term per-user memory. Facts were read from vendor and GitHub pages on Oct 25, 2026 and are Reported; what we ran ourselves is under What we measured.

Our pick: Pick Letta for agents that must remember across sessions; pick Mem0 for apps that need long-term per-user memory. No overall winner: we have not benchmarked them against each other. Updated (America/Chicago).

By Agentic Weekly, operated independently from Texas, US · Published · Last updated (America/Chicago) · How we work

Evidence: Mem0 has a Tested entry; Letta is Reported (scope on each tool page). The facts in the tables were read from each vendor's own pages and the public GitHub API on 2026-10-25 (America/Chicago) and are Reported. The What we measured section lists what we have actually run, with links to the test logs, and what we have not run yet; anything we could not confirm is marked as not captured.

Letta

Letta · v0.16.8

Reported

Platform and open-source framework for stateful agents that keep and improve memory across sessions.

Mem0

Mem0 · Python SDK v2.2.1

Tested (smoke test)

Open-source and hosted memory layer that lets agents remember users across sessions, with a free tier and published request quotas.

Side by side, from what we recorded

Each row compares one recorded fact for both tools. Rows are not weighted and nothing is added up into a score; the note under each row says what the marker means.

  • Evidence

    Reported for Letta
    Tested (smoke test) (Mem0 is ahead on this row) for Mem0

    Tested = we ran it (smoke test); Reported = we read official sources

  • GitHub stars

    25,254 for Letta
    67,804 (Mem0 is ahead on this row) for Mem0

    Attention, not quality. Read Oct 25, 2026 / Oct 25, 2026

  • Most recent release we saw

    May 14, 2026 for Letta
    Sep 25, 2026 (Mem0 is ahead on this row) for Mem0

    More recent = newer release date; says nothing about quality

  • Pricing we could verify

    Verified from official page for Letta
    Verified from official page for Mem0

    About our evidence only, not about the price

  • Steps in our setup guide

    2 for Letta
    2 for Mem0

    Counts our guide's steps, not difficulty

  • Sources we cite

    3 for Letta
    3 for Mem0

    How much we had to read; more is not better

A list of recorded differences, not a quality score or a ranking. We have not benchmarked these tools against each other; the smoke-test row links each tool's own log. How we label evidence.

What we measured

We have run Mem0 ourselves but not the other tool, so no head-to-head result exists yet. Everything else on this page is Reported from vendor and GitHub pages.

Our own tests for Letta and Mem0
TestLettaMem0
Hands-on test log (install and a real task)Not tested yet. What we will run: install, then the same one-tool agent task five times, with install time and pass rate.Tested: Mem0 mem0ai 2.2.1 (open-source Python SDK), Oct 26, 2026: passed. Mem0's open-source SDK 2.2.1 stored a fact from one chat message with a local 3B model and retrieved it with a semantic search (2.04 s) on the second attempt; the first… Full test log

How we test and label results: methodology. All test logs: test hub.

Letta vs Mem0 at a glance

Letta and Mem0 are both listed under Agent building. Agentic Weekly's Letta page names Mem0 as an alternative. Letta: Platform and open-source framework for stateful agents that keep and improve memory across sessions. Mem0: Open-source and hosted memory layer that lets agents remember users across sessions, with a free tier and published request quotas.

Letta and Mem0 side by side (vendor pages and GitHub, 2026-10-25)
FeatureLettaMem0
VendorLettaMem0
Listed underAgent buildingAgent building
LicenseApache-2.0Apache-2.0
Pricing modelFreemiumFreemium
Free tierFree: $0; includes limited agents and LLM requests with rotating free modelsFree: 10,000 add requests and 1,000 retrieval requests per month
Paid plans$20 per month plan; Teams $20 per seat per month; usage items such as $0.10 per active agent per month; Enterprise custom$19 per month (50,000 add / 5,000 retrieval); $249 per month (500,000 add / 50,000 retrieval); Enterprise custom
PlatformsCloud platform, CLI and open-source serverAPI, Python and JS SDKs, open-source self-host
Public repositoryletta-ai/letta: 25,254 stars, last push Oct 18, 2026 UTC (GitHub API, Oct 25, 2026)mem0ai/mem0: 67,804 stars, last push Oct 23, 2026 UTC (GitHub API, Oct 25, 2026)
Latest release we sawv0.16.8, May 14, 2026Python SDK v2.2.1, Sep 25, 2026
EvidenceReported from vendor pagesTested (scope on its tool page)

How Letta and Mem0 differ

  • GitHub stars on Oct 25, 2026: Mem0 67,804 (mem0ai/mem0) vs Letta 25,254 (letta-ai/letta). Stars measure attention, not quality.
  • Latest release we saw: Mem0 Python SDK v2.2.1 on Sep 25, 2026; Letta v0.16.8 on May 14, 2026 (134 days earlier).
  • Free tier: Letta: $0; includes limited agents and LLM requests with rotating free models. Mem0: 10,000 add requests and 1,000 retrieval requests per month.
  • Plans and prices differ and are not like-for-like (credits, seats and usage limits vary), so we do not name a cheaper tool. The Paid plans row above quotes each vendor's plan list as read on Oct 25, 2026.
  • Platforms as the vendors list them: Letta: Cloud platform, CLI and open-source server. Mem0: API, Python and JS SDKs, open-source self-host.

Both carry the same license: Apache-2.0. Both are listed as "Freemium", so compare the plan tables rather than the model.

Which should you pick?

  • Pick Letta if: agents that must remember across sessions. Skip it if: you want a stateless simple chatbot.
  • Pick Mem0 if: apps that need long-term per-user memory. Skip it if: you only need a vector database.

Strengths and limits

Strengths and limits as listed on each tool page
FeatureLettaMem0
StrengthsApache-2.0; Memory-first designPublished quotas; Open-source option
LimitsCredit-based usage can add up for long sessionsAdd and retrieval quotas are separate

What we did not verify

  • Letta: Behavior in practice (we have not run this tool).
  • Mem0: Benchmark claims (vendor).
  • Output quality, speed and reliability beyond the smoke tests listed under What we measured: not compared.

FAQ

Is Letta or Mem0 open source?

Letta: Apache-2.0. Mem0: Apache-2.0. Licenses come from each project's GitHub repository or the vendor's own pages, read Oct 25, 2026; read the license text itself before redistributing or building a competing service.

Does Letta or Mem0 have a free plan?

Letta: Free: $0; includes limited agents and LLM requests with rotating free models. Mem0: Free: 10,000 add requests and 1,000 retrieval requests per month. Checked Oct 25, 2026; prices and limits change, so confirm on each vendor's page.

Which was updated more recently, Letta or Mem0?

Letta's newest release we saw is v0.16.8 (May 14, 2026); Mem0's is Python SDK v2.2.1 (Sep 25, 2026). Read Oct 25, 2026 from the official release page or repository; a newer date is not a quality ranking.

What is the main difference between Letta and Mem0?

GitHub stars on Oct 25, 2026: Mem0 67,804 (mem0ai/mem0) vs Letta 25,254 (letta-ai/letta). Stars measure attention, not quality. Latest release we saw: Mem0 Python SDK v2.2.1 on Sep 25, 2026; Letta v0.16.8 on May 14, 2026 (134 days earlier).

Sources

Page history

  • : First published. Facts read from vendor pages and the GitHub API on 2026-10-25.

Markdown version for agents: /compare/letta-vs-mem0.md