code.install counted upgrades and repeat sessions. Session start records install whenever is_first_run() is true, and that only checked whether telemetry-identity.json exists. Recording install does not create that file — only the first successful flush does. So install fired for every 0.2.x user on their first 0.3.x session (0.2.x never wrote the file, and the data directory survives the upgrade), again for any session starting before that first flush finished, and — this is the part that makes it unbounded rather than a race — on every single session, forever, for anyone whose flush never succeeds. An offline or firewalled user reported a new install every time they opened an editor, which is exactly the population hardest to see in the data. A dedicated install-state.json is now claimed with O_CREAT|O_EXCL at the moment install is recorded, so two sessions starting together cannot both win, and the marker is not coupled to identity. Deliberately not the identity file: writing that from a recording process would race the sender, which writes it during resolve_distinct_id, and overloading it is what caused this. Upgrade detection keys on the data directory already having content. A fresh install has an empty one; anything else predates this session. That is a firmer predicate than looking for 0.2.x's venv/ and requirements.txt, which is a guess about files another part of the plugin may or may not have written and only ever works for this one upgrade. The version is stored in the marker so later changes record code.upgrade with a real from_version. A cached email outlived an API key change. resolve_distinct_id kept the first email it resolved and never looked again, so switching to a key from another account kept attributing events to the previous one. It now stores a fingerprint of the key the email came from and re-resolves when the current key differs, and falls back to the anonymous id when no key is configured rather than continuing to attribute to an account it cannot verify. The dangerous part is the alias. resolve_distinct_id's second return value becomes a PostHog $identify with $anon_distinct_id, and aliasing one account email to another merges two real person profiles irreversibly. The re-resolve path returns no alias; aliasing runs anonymous to email only, and never email to email. One existing test asserted that is_first_run flips when the identity file is written, which is the defect itself. Rewritten, along with coverage for atomic claiming, upgrade detection and version changes. Claude-Session: https://claude.ai/code/session_01C7tEmH86HAr7GoAAKCEHZb
Learn more · Join Discord · Demo
📄 Benchmarking Mem0's token-efficient memory algorithm →
New Memory Algorithm (April 2026)
| Benchmark | Old | New | Tokens | Latency p50 |
|---|---|---|---|---|
| LoCoMo | 71.4 | 92.5 | 7.0K | 0.88s |
| LongMemEval | 67.8 | 94.4 | 6.8K | 1.09s |
| BEAM (1M) | — | 64.1 | 6.7K | 1.00s |
| BEAM (10M) | — | 48.6 | 6.9K | 1.05s |
All benchmarks run on the same production-representative model stack. Single-pass retrieval (one call, no agentic loops) at a top_200 retrieval budget. Scores reflect Mem0's managed platform, which includes proprietary optimizations not available in the open-source SDK; open-source users should expect directionally similar gains but not identical numbers.
What changed:
- Single-pass ADD-only extraction -- one LLM call, no UPDATE/DELETE. Memories accumulate; nothing is overwritten.
- Agent-generated facts are first-class -- when an agent confirms an action, that information is now stored with equal weight.
- Entity linking -- entities are extracted, embedded, and linked across memories for retrieval boosting.
- Multi-signal retrieval -- semantic, BM25 keyword, and entity matching scored in parallel and fused.
- Temporal Reasoning -- time-aware retrieval that ranks the right dated instance for queries about current state, past events, and upcoming plans.
See the migration guide for upgrade instructions. The evaluation framework is open-sourced so anyone can reproduce the numbers.
Research Highlights
- 92.5 on LoCoMo -- +21 points over the previous algorithm
- 94.4 on LongMemEval -- +27 points, with 98.2 on assistant memory recall
- 64.1 on BEAM (1M) -- production-scale memory evaluation at 1M tokens
- Read the full paper
Introduction
Mem0 ("mem-zero") enhances AI assistants and agents with an intelligent memory layer, enabling personalized AI interactions. It remembers user preferences, adapts to individual needs, and continuously learns over time—ideal for customer support chatbots, AI assistants, and autonomous systems.
Key Features & Use Cases
Core Capabilities:
- Multi-Level Memory: Seamlessly retains User, Session, and Agent state with adaptive personalization
- Developer-Friendly: Intuitive API, cross-platform SDKs, and a fully managed service option
Applications:
- AI Assistants: Consistent, context-rich conversations
- Customer Support: Recall past tickets and user history for tailored help
- Healthcare: Track patient preferences and history for personalized care
- Productivity & Gaming: Adaptive workflows and environments based on user behavior
🚀 Quickstart Guide
Sign up as an agent
AI agents can mint a working Mem0 API key in under five seconds — no email, no dashboard, no OTP. Four commands end-to-end:
# 1. Install
npm install -g @mem0/cli # or: pip install mem0-cli
# 2. Sign up as an agent (replace `claude-code` with your name)
mem0 init --agent --agent-caller claude-code
# 3. Add a memory
mem0 add "I am using mem0"
# 4. Search
mem0 search "am I using mem0"
The human owner can claim the account later with mem0 init --email <their-email> — same key, memories preserved. Full guide: Sign up as an agent.
| Library | Self-Hosted Server | Cloud Platform | |
|---|---|---|---|
| Best for | Testing, prototyping | Teams running on their own infrastructure | Zero-ops production use |
| Setup | pip install mem0ai |
docker compose up |
Sign up at app.mem0.ai |
| Dashboard | -- | Yes | Yes |
| Auth & API Keys | -- | Yes | Yes |
| Advanced Features | -- | Teasers | All included |
Just testing? Use the library. Building for a team? Self-hosted. Want zero ops? Cloud.
Library (pip / npm)
pip install mem0ai
For enhanced hybrid search with BM25 keyword matching and entity extraction, install with NLP support:
pip install mem0ai[nlp]
python -m spacy download en_core_web_sm
Install sdk via npm:
npm install mem0ai
Self-Hosted Server
Note: Self-hosted auth is on by default. Upgrading from a pre-auth build? Set
ADMIN_API_KEY, register an admin through the wizard, orAUTH_DISABLED=truefor local dev only. See upgrade notes.
# Recommended: one command — start the stack, create an admin, issue the first API key.
cd server && make bootstrap
# Manual: start the stack and finish setup via the browser wizard.
cd server && docker compose up -d # http://localhost:3000
See the self-hosted docs for configuration.
Cloud Platform
- Sign up on Mem0 Platform
- Embed the memory layer via SDK or API keys
- Using hosted Qdrant vectors? See the Platform migration guide to import them into Mem0 Platform.
CLI
Manage memories from your terminal:
npm install -g @mem0/cli # or: pip install mem0-cli
mem0 init
mem0 add "Prefers dark mode and vim keybindings" --user-id alice
mem0 search "What does Alice prefer?" --user-id alice
See the CLI documentation for the full command reference.
Agent Skills
Teach your AI coding assistant (Claude Code, Codex, Cursor, Windsurf, OpenCode, OpenClaw, and any tool that supports the skills standard) how to build with Mem0. Two categories:
Reference skills — always on (SDK knowledge loaded into the assistant's context):
npx skills add https://github.com/mem0ai/mem0 --skill mem0
npx skills add https://github.com/mem0ai/mem0 --skill mem0-cli
npx skills add https://github.com/mem0ai/mem0 --skill mem0-vercel-ai-sdk
Pipeline skills — run on demand (execute an end-to-end workflow in an existing repo):
npx skills add https://github.com/mem0ai/mem0 --skill mem0-integrate
npx skills add https://github.com/mem0ai/mem0 --skill mem0-test-integration
npx skills add https://github.com/mem0ai/mem0 --skill mem0-oss-to-platform
Use /mem0-integrate to wire Mem0 into an existing repo via a test-first pipeline, then /mem0-test-integration to verify. Use /mem0-oss-to-platform to migrate an existing project from Mem0 OSS to the hosted Platform SDK. See the skills catalog or Vibecoding with Mem0 for the full picture.
Basic Usage
Mem0 requires an LLM to function, with gpt-5-mini from OpenAI as the default. However, it supports a variety of LLMs; for details, refer to our Supported LLMs documentation.
Mem0 uses text-embedding-3-small from OpenAI as the default embedding model. For best results with hybrid search (semantic + keyword + entity boosting), we recommend using at least Qwen 600M or a comparable embedding model. See Supported Embeddings for configuration details.
First step is to instantiate the memory:
from openai import OpenAI
from mem0 import Memory
openai_client = OpenAI()
memory = Memory()
def chat_with_memories(message: str, user_id: str = "default_user") -> str:
# Retrieve relevant memories
relevant_memories = memory.search(query=message, filters={"user_id": user_id}, top_k=3)
memories_str = "\n".join(f"- {entry['memory']}" for entry in relevant_memories["results"])
# Generate Assistant response
system_prompt = f"You are a helpful AI. Answer the question based on query and memories.\nUser Memories:\n{memories_str}"
messages = [{"role": "system", "content": system_prompt}, {"role": "user", "content": message}]
response = openai_client.chat.completions.create(model="gpt-5-mini", messages=messages)
assistant_response = response.choices[0].message.content
# Create new memories from the conversation
messages.append({"role": "assistant", "content": assistant_response})
memory.add(messages, user_id=user_id)
return assistant_response
def main():
print("Chat with AI (type 'exit' to quit)")
while True:
user_input = input("You: ").strip()
if user_input.lower() == 'exit':
print("Goodbye!")
break
print(f"AI: {chat_with_memories(user_input)}")
if __name__ == "__main__":
main()
For detailed integration steps, see the Quickstart and API Reference.
🔗 Integrations & Demos
- ChatGPT with Memory: Personalized chat powered by Mem0 (Live Demo)
- Browser Extension: Store memories across ChatGPT, Perplexity, and Claude (Chrome Extension)
- Langgraph Support: Build a customer bot with Langgraph + Mem0 (Guide)
- CrewAI Integration: Tailor CrewAI outputs with Mem0 (Example)
📚 Documentation & Support
- Full docs: https://docs.mem0.ai
- Community: Discord · X (formerly Twitter)
- Contact: founders@mem0.ai
Citation
We now have a paper you can cite:
@article{mem0,
title={Mem0: Building Production-Ready AI Agents with Scalable Long-Term Memory},
author={Chhikara, Prateek and Khant, Dev and Aryan, Saket and Singh, Taranjeet and Yadav, Deshraj},
journal={arXiv preprint arXiv:2504.19413},
year={2025}
}
⚖️ License
Apache 2.0 — see the LICENSE file for details.