MemOS

MemOS is an open-source memory operating system for large language models and AI agents, with nearly 12,000 stars on GitHub, giving agents ultra-persistent long-term memory, hybrid retrieval, and reusable skills across tasks.

Overview

Stateless chat is the biggest practical limit of today’s agents: every new session starts from zero, and stuffing everything into the context window is expensive and noisy. MemOS treats memory the way an operating system treats storage — as a managed layer with structure, scheduling, and lifecycle control. Memories are organized in a layered architecture, retrieved through a hybrid of semantic search and structured lookup, and shared across models, devices, and applications through a common protocol, so what an agent learns in one place can follow it to another. The system is self-evolving: it consolidates experience into reusable skills, and the team reports 35.24% token savings from not re-teaching the agent the same context. MemOS exposes a unified API for preserving, updating, transferring, and rolling back memories, supports MCP for agent integration, and deploys on public cloud, private cloud, on-premises, or hybrid setups. It is Apache-2.0 licensed and developed by MemTensor with an active open-source community.

Key Features

• Persistent long-term memory – agents remember users, facts, and outcomes across sessions and tasks.
• Hybrid retrieval – semantic search combined with structured memory lookup for relevant, fast recall.
• Self-evolving skills – repeated experience is distilled into reusable skills, cutting token usage.
• Cross-model, cross-device sharing – memory stays portable between apps and agent frameworks.
• Full lifecycle API – preserve, update, transfer, and roll back memories through one interface.
• MCP and framework support – integrates with agent frameworks, RAG setups, and major model ecosystems.
• Flexible deployment – public cloud, private cloud, on-premises, or hybrid architectures.

💳 Pricing

MemOS is free and open source under the Apache-2.0 license for self-hosting. The managed MemOS Cloud offers a free tier with monthly memory and chat API allowances, plus paid Starter, Pro, and custom Enterprise plans for production scale.

Who Is It For

Agent builders and platform teams whose chatbots, copilots, and autonomous agents need to remember users and learn across sessions — without burning their budget on ever-growing context windows.