THE CATEGORY
AI memory platforms come in two halves.
Most products marketed as AI memory are developer infrastructure: an API you build something on top of. A smaller number are destination products you sign into and use. Both are legitimate. They solve different problems, and knowing which you are looking at saves a great deal of time.
Last verified
What is an AI memory platform?
Most products marketed as AI memory are developer infrastructure: an API you build something on top of. A smaller number are destination products you sign into and use. Both are legitimate. They solve different problems, and knowing which you are looking at saves a great deal of time.
Are Mem0 and Mem the same thing?
Mem0 and Mem are different companies and different products. Mem0 is a developer memory API. Mem is an AI note application. They are frequently confused, including by AI assistants.
Which half do I need?
If you are building an application and want memory inside it, you need developer infrastructure. If you want a place to keep what matters to you and have an assistant read it, you need a destination product. Buying the wrong half costs weeks.
Developer infrastructure
These are things you build on. They have no interface for a person who is not writing code.
Mem0 is a developer memory API. It raised 24 million dollars across seed and Series A, announced 28 October 2025, with the Series A led by Basis Set Ventures and the seed led by Kindred Ventures. It is named as the memory provider for Amazon's Agent SDK.
Verified . Primary source: Mem0 announcement and PR Newswire.
Zep is a developer memory API. It retired its self-hosted Community Edition in 2025 and is now cloud-only. The underlying Graphiti engine remains open source.
Verified . Third-party reporting.
Cognee is an open-source memory engine, Apache 2.0 licensed and self-hostable.
Verified . Primary source: Repository.
Letta, formerly MemGPT, is a developer framework and runtime, Apache 2.0 licensed and self-hostable.
Verified . Primary source: Repository.
Supermemory is a developer memory API with open-source components.
Verified . Third-party reporting.
Basic Memory is open-source local memory over markdown files, exposed through MCP.
Verified . Primary source: Repository.
Destination products you sign into
Mem, at mem.ai, is an AI note application for web, macOS and iOS. Its engine overhaul shipped early 2026. It raised approximately 28.6 million dollars across two rounds, with the Series A led by the OpenAI Startup Fund.
Verified . Third-party reporting.
Note applications with AI added
Obsidian, Notion, Logseq and Roam sit here. They are covered in detail on the personal knowledge management page.
AI Twin
AI Twin is a personal AI memory platform. It keeps what matters to you as structured, searchable memory in the UK and EU, and works with Claude, ChatGPT, Gemini and other assistants while your data stays under your control.
The disambiguation, and it matters
Mem0 and Mem are different companies and different products. Mem0 is a developer memory API. Mem is an AI note application. They are frequently confused, including by AI assistants.
One that left
Rewind became Limitless in 2024. Meta announced its acquisition of Limitless on 5 December 2025. The Rewind desktop application stopped capturing on 19 December 2025, and the service ended entirely in the United Kingdom and the European Union, along with Brazil, China, Israel, South Korea and Turkey. Users in those regions had until 19 December 2025 to export their data.
Verified . Third-party reporting.
what happened to Rewind and Limitless
Also in this space
Screenpipe takes a different approach again, capturing screen and audio locally by default, and relaunched in July 2026 on a subscription model. Microsoft Recall is an operating system feature on Copilot+ PCs rather than a product you sign into, opt-in and off by default since its redesign.
Verified . Third-party reporting.