If you've been searching for AI memory apps that connect to Gmail and Notion, you've probably landed on two names: hippocampOS and Mem. Both promise to fix the same core frustration — your AI assistant keeps forgetting everything you've already told it — but they solve that problem in meaningfully different ways. This comparison breaks down what each tool actually does, where each one falls short, and which one fits how you work.
What each tool is actually trying to do
Mem (get.mem.ai) is an AI-native workspace and note-taking tool. It ingests your notes, meeting summaries, and connected app data, then surfaces relevant information through an AI assistant designed to act as a kind of chief-of-staff. The core experience is a Mem-hosted workspace where your information lives and where you interact with it.
hippocampOS takes a different approach entirely. Instead of being a workspace you move into, it acts as a memory layer that sits between your existing tools and the AI models you already use. It connects to Gmail, Notion, Granola, and local files, organizes everything into a structured memory graph with source provenance tracked throughout, and injects the right context directly into Claude or ChatGPT conversations. You don't switch apps. You stay in the AI chat you already have open.
That architectural difference shapes almost every comparison that follows.
Feature-by-feature comparison
hippocampOS connects to Gmail, Notion, Granola, and local files natively. Mem covers Gmail and Notion but not Granola or local files. Both offer a no-code setup, but hippocampOS is designed specifically to inject context into Claude and ChatGPT, while Mem keeps AI interaction inside its own workspace.
hippocampOS uses a structured memory graph with source provenance and role-scoped named brains. Mem uses a note-based model inside a single workspace without role separation. Retrieval in hippocampOS uses vector search without an LLM call in the retrieval path, keeping token usage efficient.
On sync cadence: hippocampOS runs nightly on the Spark plan and on-demand on Synapse and Cortex. Mem offers more continuous sync. hippocampOS does not use your Google user data to train generalized AI models.
Comparison table
Swipe horizontally to see every column.
| Tool | Best for | Claude and ChatGPT | Pricing | Key limitation |
|---|---|---|---|---|
| hippocampOS | Users of Claude and ChatGPT who want persistent memory from Gmail, Notion, Granola, and local files | Yes — injects context directly into both | $5/mo billed annually (Spark plan); 7-day refund guarantee | Nightly sync on Spark plan; newer product with an expanding integration set |
| Mem (get.mem.ai) | Users who want an AI-native workspace to consolidate notes and knowledge | No — Mem uses its own AI, not Claude or ChatGPT | Higher entry pricing; check Mem's current plans | No role-scoped named brains; no context injection into Claude or ChatGPT |
Mem builds a smarter workspace. hippocampOS builds a smarter version of the AI tools you already use.
Connecting to Gmail and Notion
Both tools offer Gmail and Notion connectivity, but the purpose and depth are different.
In Mem, connected apps feed your Mem workspace. You read and search your information inside Mem's interface, and Mem's AI assistant helps you make sense of it. That's useful if you want a single place to review everything — but it means you're working inside Mem rather than inside Claude or ChatGPT.
In hippocampOS, those same connections feed a persistent memory graph that tracks where every piece of information came from. When you invoke a brain inside Claude or ChatGPT, the retrieval layer pulls the most relevant nodes from that graph and injects them as context for your conversation. You stay in Claude. You stay in ChatGPT. The memory just shows up.
hippocampOS also connects to Granola and local files, which Mem doesn't support. For anyone whose work spans meeting notes, documents, email threads, and Notion pages, that breadth matters.
One important note on Gmail data: hippocampOS does not use your Google user data to train generalized AI models.
Named brains and role separation
This is one of the clearest differentiators between the two tools.
hippocampOS lets you create named brains for different roles in your life — a Work brain, a Client: Acme brain, a Personal brain. When you invoke a specific brain in a conversation, only that brain's context gets injected. There's no bleed between roles. Your personal notes don't surface in a client conversation. Your client details don't show up in a personal planning session.
Mem has no equivalent concept. Your information lives in one workspace, and while you can use tags or collections to organize it, there's no role-scoped context layer designed to control what gets surfaced in different kinds of conversations.
For consultants, freelancers, or anyone managing multiple clients or wearing multiple hats, that separation isn't a nice-to-have. It's the difference between a memory system you can trust and one you have to second-guess.
Injecting memory into Claude and ChatGPT
Mem isn't built to inject memory into Claude or ChatGPT as an external context layer. If those are your primary AI tools, Mem doesn't extend them. You'd need to copy information out of Mem and paste it in manually — which defeats the purpose.
hippocampOS is built specifically for this use case. The no-code setup means no API configuration, no custom prompts. You invoke a brain, the relevant context from your Gmail threads, Notion pages, Granola notes, and local files gets pulled in, and your conversation has the background it needs.
The retrieval mechanism is also worth understanding. hippocampOS uses vector retrieval without making an LLM call in the retrieval path. That means finding the right context doesn't burn your token budget before your actual conversation even starts.
hippocampOS extends Claude and ChatGPT's native memory — it doesn't replace it, and it doesn't claim compatibility with other LLMs beyond those two.
Sync cadence: what to expect
On the Spark plan, hippocampOS syncs nightly. If you add something to Notion at 9am and open a brain at 10am, that update won't be in the graph yet. The Synapse and Cortex plans offer on-demand sync, which closes that gap.
Mem offers more continuous sync, which is a genuine advantage if real-time freshness is critical to your workflow.
For most Spark users, nightly sync is sufficient. Email threads, meeting notes, and documents accumulate context over days and weeks — the memory compounds over time, and a few-hour lag rarely matters in practice. But if you need to pull in something from a meeting that just ended, upgrading to Synapse or Cortex is the right move.
Pricing and getting started
The Spark plan starts at $5 per month billed annually, making hippocampOS one of the most accessible entry points for a structured AI memory layer. There's also a 7-day refund guarantee if it doesn't fit your workflow.
Mem's pricing sits higher, and the value proposition is different — you're paying for a workspace product, not a context injection layer.
If you're already happy with Claude or ChatGPT and want them to know your work better, hippocampOS is the more direct answer. If you want to move your note-taking and knowledge management into an AI-native workspace and do most of your AI-assisted work inside that environment, Mem is worth evaluating on its own terms.
Which one should you choose?
Choose Mem if you want an AI-native workspace to consolidate your note-taking, and you're comfortable doing most of your AI-assisted work inside Mem's own interface.
Choose hippocampOS if you want to keep using Claude or ChatGPT and give them persistent, structured memory from Gmail, Notion, Granola, and local files — especially if you manage multiple roles, clients, or projects and need clean separation between them.
The two tools are solving related but distinct problems. Mem builds a smarter workspace. hippocampOS builds a smarter version of the AI tools you already use.
The Spark plan is $5/month billed annually at hippocampos.io.
Frequently asked questions
Does hippocampOS work with both Claude and ChatGPT?
Yes. hippocampOS injects memory context directly into both Claude and ChatGPT. It does not claim compatibility with other LLMs beyond those two.
Can Mem inject memory into Claude or ChatGPT?
No. Mem is an AI-native workspace with its own AI assistant. It isn't designed to inject context into Claude or ChatGPT as an external memory layer.
Does hippocampOS use my Gmail data to train AI models?
No. hippocampOS does not use your Google user data to train generalized AI models.
What's the difference between hippocampOS's named brains and Mem's collections?
Named brains in hippocampOS are role-scoped context layers. When you invoke a specific brain, only that brain's memory is injected into your conversation — with no bleed from other brains. Mem's collections are organizational tags within a single workspace and don't create separated context layers for AI injection.
How often does hippocampOS sync with Gmail and Notion?
On the Spark plan, sync runs nightly. On Synapse and Cortex plans, sync is on-demand, so you can pull in the latest information whenever you need it.
Does hippocampOS replace Claude or ChatGPT's built-in memory?
No. hippocampOS extends the native memory of Claude and ChatGPT by injecting structured, source-tracked context from your connected tools. It works alongside native memory, not instead of it.
What does the Spark plan cost, and is there a trial?
The Spark plan starts at $5 per month billed annually. hippocampOS offers a 7-day refund guarantee if the product doesn't meet your needs.