The knowledge base for ChatGPT & Claude
Give ChatGPT & Claude
long-term memory.
A simple knowledge base your AI can actually read. Save notes once. Stop re-explaining yourself.
Free to start. No credit card required.
How it works
Three steps. Two minutes.
No new habits. Your AI does the reading and writing.
Write or clip a note
Plain Markdown. Architecture decisions, customer interviews, trip notes. Anything you'd otherwise re-explain. Clip from the web with the Chrome extension.
Connect ChatGPT or Claude
One-click from the ChatGPT Apps Directory or OAuth into Claude. Two lines of config for Cursor and friends, or a custom connector for Perplexity.
Your AI reads and updates
It searches your notes when you ask a question, and writes back what it learned, so the next conversation already knows it. Working in a terminal? Codex CLI hooks save every session on their own. You stop re-pasting context.
The problem
Sound familiar?
Claude starts every session from zero
You explained the whole thing last week. Today Claude remembers none of it. So you explain it again. Every conversation starts from scratch.
Your knowledge is scattered
Notes in one app. Docs in another. The one detail you need buried in an old chat. Your AI can't see any of it.
Your tools do too much
Notion has 47 features you don't use. Every other app wants to run your whole life. You just want to write something down and have your AI remember it.
More on this on the blog.
Maintained, not just saved
Built-in AI memory only remembers. Hjarni keeps it true.
Facts change. You switch jobs, reverse a decision, raise a price. Memory that only appends goes stale. In Hjarni, Claude and ChatGPT find the note that is now wrong and fix it.
Updating beats creating.
notes-update is the most called tool on Hjarni's built-in MCP server. More calls than notes-create. In real use, your AI spends more time correcting and merging notes than writing new ones. That is the difference between a pile and a memory.
One fact, one place.
Say what changed. Your AI rewrites the note that says otherwise. No second note contradicting the first.
Every edit is visible.
Notes show what changed and who changed it, you or your AI. Review it, or change it back.
Better in month six than week one.
Long-time users edit old notes as often as they write new ones. Stored memory piles up. Maintained memory pays off.
About me › Work
Updated just now
Work and role
Senior engineer at Acme, payments team.
Staff engineer at Vektor, infrastructure team.
Prefers async standups. Mentors two juniors.
Created in January. Merged a duplicate in March. Corrected by Claude today.
One note, kept current. Not three notes that disagree.
The idea
A memory that grows more valuable every day.
Hjarni isn't just somewhere to jot things down. It's a memory you build once and keep for good. Every note you add makes your AI a little sharper about your world: your decisions, your standards, the way you work. Switch tools, add teammates, come back in a year: it's all still there, still yours, still in use.
It compounds
A generic assistant stays generic. Yours gets better the more you teach it, because everything you save sticks around and adds up.
One memory for every AI
Write it once and ChatGPT, Claude, and whatever you use next all read from the same place. No copying between apps.
It belongs to you
Your knowledge isn't locked inside someone else's product. It's plain Markdown you can read, export, and take anywhere.
What makes Hjarni different
Your AI works the way you work.
Each folder teaches Claude and ChatGPT how to handle what's inside. You write the rules once. Every AI follows them.
You own the instructions.
Your projects folder leads with the current status. Your meetings folder puts decisions and action items up front. Your contacts folder records who owns what. Claude and ChatGPT read the rules before they touch a note.
Folders inherit from their parents.
A rule on a parent folder applies to everything inside it. A child folder can add more, or override.
Teams have their own.
Set the conventions once. Every teammate's Claude and ChatGPT follow them.
No prompting. No copy-paste.
The rules ride along with the note. Whichever AI is reading it gets them automatically.
Your brain
Rules stack on the way down
-
Personal brain-level
"Prefer bullets over paragraphs. Lowercase titles."
-
Projects
"Open with the current status and the deadline."
-
Launch you're here
"List the next step and who owns it."
Claude and ChatGPT read all three when they open a note in Launch.
From the people who use it
Hjarni ran the whole Labeur launch. Scope decisions, landing page copy, App Store submission, launch day checklist, all in one place and all in sync with Claude. I stopped re-explaining myself to the AI. From first sketch to live in the store.
What sold me was how light and well defined the MCP is. My AI used to choke when I pasted Markdown and config files into a chat. It reads them perfectly from Hjarni.
Features
Simple on purpose.
Less software. More thinking.
Built for ChatGPT and Claude
Full REST API and native MCP server. Your AI reads and writes your notes directly. Set up ChatGPT or Claude in minutes.
Also for Cursor, Claude Code, Windsurf, and Cline.
Markdown, end to end
Notes are plain Markdown, the format your AI already speaks. No conversion. No lock-in.
Dump ideas fast
The inbox catches everything. Sort later. Don't let organizing slow down thinking.
Clip the web
One click on any article saves a clean Markdown copy to your inbox. Get the Chrome extension.
Connect your thinking
Wiki-links between notes. Build a web of knowledge, not a pile.
Share a folder publicly
Turn any folder into a read-only public page. No sign-up for whoever you send the link to. See how.
Your data is yours
Export everything as Markdown in a ZIP. Always.
Automate with Zapier
Connect Hjarni to 9,000+ apps. No code. Notes arrive automatically, and your AI can use them right away. Set up Zapier
The loop
Every new chat starts from zero. Yours doesn't have to.
Work it out in Claude. Save it to Hjarni. Pick up right where you left off. Repeat.
Teams
One person writes it down. Everyone's AI knows it.
Share a folder. Everyone's AI catches up instantly.
Write once, the whole team remembers
One person writes down how it works. Now everyone's AI knows it. No more "did you see that doc?"
Set rules once, the whole team follows
Write down how your team does things once. Everyone's AI follows it, new people included. No more starting from zero.
Simple pricing
Free plan forever. No credit card. No hidden fees.
Free
Try MCP memory with a small note base.
$0
forever
- Up to 25 notes
- Folders, tags & search
- Full MCP & API access
Pro
Personal long-term memory for ChatGPT and Claude.
$10/month
Billed monthly
or $99/year (2 months free)
- Unlimited notes. No 25-note cap, keep everything your AI should remember.
- File attachments. Attach PDFs, images, and docs to any note.
- Shared folders. Collaborate with up to 2 people on a folder.
- Public sharing. Publish a folder as a read-only page.
- Everything in Free. All your current notes, untouched.
Teams
Shared memory for a team's AI tools.
$13/seat/month
Billed monthly
or $129/seat/year (2 months free)
- Shared knowledge base
- Team MCP & API access
- Member management
- Billed separately from personal
- Everything in Pro
Need SSO, SCIM, role-based access, or a per-team audit log? Read about Enterprise or talk to us.
Common questions
Is this just another note-taking app?
No. It's a knowledge base your AI can actually use. Your notes become live context for every AI conversation.
Why not Notion or Obsidian?
Great tools. Different goals. Hjarni is built from the ground up for AI. Custom instructions per folder. Team-wide AI conventions. An MCP server designed around your knowledge, not bolted onto a workspace. See how Hjarni compares to Notion, Obsidian, ChatGPT Projects, Claude Projects, and Apple Notes.
What's MCP?
Model Context Protocol. An open standard that lets AI assistants connect to external tools and data. Hjarni has a built-in MCP server. Your AI reads and writes your notes directly.
Which AI assistants work with Hjarni?
ChatGPT and Claude connect via MCP today. Any AI that supports MCP will work automatically. Others can use the REST API.
How do I give my AI a memory?
Add Hjarni as an MCP server in ChatGPT or Claude. Takes two minutes. Every conversation picks up where the last one left off.
What happens to my data?
Your notes live on our servers. Export everything as Markdown anytime. We don't train AI on your data. We don't sell it. It's yours.
Can I collaborate with others?
Yes. Create a team, invite members, share folders. Everyone's AI benefits from the shared knowledge.
Can I self-host Hjarni?
Not currently. It's a hosted service. That keeps things simple, for you and for us.
Give your AI a memory
Write once. You both remember.
Free to start. No credit card required.
Works with Claude and ChatGPT today. Gemini coming soon.