OpenAI's built-in memory (in ChatGPT and, in a different form, Assistants) is convenient — it just works inside OpenAI's products. Mem0 is a memory API you control and can use anywhere. The gap that matters is portability: built-in memory can't leave the app it lives in, while an API-based memory follows your agent everywhere. (Looking at the whole field? See our roundup of the best memory for AI agents.)
Mem0 vs OpenAI memory at a glance
| Mem0 | OpenAI memory | |
|---|---|---|
| Where it works | Any agent / app you build | Inside ChatGPT / Assistants |
| Portable across tools | Yes | No |
| You can build on it | Yes (API) | No |
| Model lock-in | None | OpenAI only |
When to choose Mem0
Choose Mem0 (or any memory API) when you're building a product or multi-tool workflow and need memory that's portable, programmable, and not tied to one vendor's model.
When to choose OpenAI memory
OpenAI's memory is fine if you only ever work inside ChatGPT and don't need that memory anywhere else.
Where Kit for AI fits
If you want one memory shared across every tool — Cursor, Claude Code, your own app — and you want it to read your documents too, Kit for AI gives you portable remember/recall plus document knowledge bases over one API and MCP, with per-user namespaces. Switch models and your memory comes with you.
Related reading
Go deeper: share one memory across AI models · the AI memory API — or start with the complete guide to persistent memory for AI.
Want memory that reads your documents too, across every tool you use? Start free and connect over MCP or the REST API.