A letter for my fellow viewers

Hi.

If you're reading this, a link probably landed in your inbox or DM, or someone said "Maheen built a thing." Welcome. Pull up a chair. This is a letter, not a pitch.

I was using a second brain before it was a thing. Back when Notion was still a small startup, Obsidian wasn't out, Roam was the cool kids' club, and the term hadn't gone mainstream yet. I had a tangle of plaintext files, dated journals, half-typed thoughts I came back to two years later, and they actually mattered. Decisions I'd forgotten the reasoning for. Problems I'd already solved once. Taste I'd built and then abandoned. The notebook was working.

Then Karpathy launched llm.wiki, and the second-brain idea finally got the language it deserved. The curation is the value, not the notes themselves. Every person's reasoning is unique, so every person's curation reflects something nobody else has. That single insight made a lot of what I'd been doing feel less like a private hobby and more like infrastructure.

But the notebook still couldn't leave my hard drive. That was the wall.

The problem

I've been working in software for a while, most recently building agentic systems. And the wall that kept blocking me wasn't an engineering one. It was a sharing one.

I always had this problem at my company, sharing my notes (which were, obviously, my second brain) with the rest of the leadership. We needed to sync brains. Mine and theirs. So the optimal output for the company wasn't drifting in private notebooks no one else could see, and so the people calling shots were actually aligned on the same goals for the same reasons.

Notion docs that everyone agrees to read but nobody does. Didn't work. Slack threads that scroll away forever. Didn't work. Whiteboards that get erased. Didn't work. The medium was eating the message.

And the other half of the problem was just as bad. It was hard to share the abstracted thinking down to non-leadership teammates (engineers, designers, ops) in a form they could actually use to do their work. The substrate was getting compressed into a one-line summary by the time it reached them, losing everything that made the original thinking useful, and then I was the one frustrated when their output didn't reflect the reasoning behind it.

I needed a way to lend a slice of my brain to a specific audience, with the wikilinks intact, the structure intact, the texture of how I actually think intact. Not a summary. The substrate.

So I built BrainShare as a beginning of trying to solve those problems. I hope to find a better solution soon. This is what I have right now.

What it is

BrainShare is a plugin for Obsidian, the note-taking app a lot of us already use, plus a tiny server that runs on Cloudflare. You pick a slice of your vault (a folder, a few notes, a project), and it gives you a URL. The recipient gets your notes, with the wikilinks still working, the backlinks rendered, the canvases visible, the tags clickable, full-text search across everything. Your second brain, addressable.

If you want it private, drop a token on it, one URL per person, expirable, revocable, view-count-capped. If you want it public, leave it open. Your call, per slice.

It's free. The plugin is MIT-licensed. The whole backend runs on Cloudflare's free tier. There's no signup, no email gate, no "talk to sales," no upsell screen. You can self-host the entire stack on your own Cloudflare account in about 60 seconds. The walkthrough is in Install BrainShare in 60 Seconds.

Giving this cool plugin away for FREE feels right. If you get value from it, pay me back by publishing your own brain.

Looks like Obsidian on the web. Isn't.

Yeah, the page you're reading has a sidebar tree, wikilinks, backlinks, a graph, a properties panel. That's intentional. If you already use Obsidian, your reader shouldn't have to learn a new interface to read your slice. The chrome on purpose looks like what you already know.

But the surface isn't the thing.

Obsidian Publish ends at making your notes look nice on a URL, for $96/year, on infra you don't control, with no extension point, no API, no per-recipient access. BrainShare starts there and keeps going. Every note has a stable identity (ULIDs, not filenames). Every share is scoped to an audience with a real auth gate. Every page is queryable by an AI agent at the same URL a human reads. The slice you're on right now? It's not just a publication. It's an open protocol you can build on.

If Obsidian Publish were $0 and open-source and agent-callable, I wouldn't have built this. It isn't. So I did.

This is a published version of Obsidian on the surface and a different thing entirely underneath. The real thing is the protocol. Second brains, addressable, gateable, linked to other people's brains, in your hands. Not on someone's SaaS dashboard.

A thank-you I actually mean

I don't know if u peeps were using the best of Cloudflare. I do.

Cloudflare KV namespace is an underrated thing. It's the entire backend of BrainShare, no Postgres, no Redis, no S3, no managed database somewhere. Just KV, served from the edge, on every Cloudflare datacenter in the world. The free tier handles real launch traffic. The deploy is one command. This is what infrastructure should feel like, and most people sleep on it because they reach for Postgres by reflex.

I wrote out the longer version of this in A Thank-You to Cloudflare. If you're into infra, read that one.

If you're a nerd about how the rendering actually works (how raw markdown turns into Obsidian-style HTML at the edge, why every page is a single self-contained HTTP response, why there's no client framework involved), that's all in How BrainShare Works (Behind the Scenes).

The bigger thing

I think most people's second brains will never leave their hard drive, and that's a quiet loss for everyone.

Not because everyone should publish everything, that broke personal blogs in 2015 and it'll break this too if we aren't careful. But because there's a missing middle. A curated slice, shared with a specific audience, on your own terms. That middle is where the value compounds.

The dream is many brains, lightly composed. Mine linking to yours. Yours linking to a friend's. ULIDs hold each note's identity so the links survive renames and reorgs. Federation is opt-in subscription, not a global feed. None of it is a wiki. None of it is a timeline. The longer version of that bet is in Many Brains, One Web.

It might not work. The noise floor might still win. But the primitives are right and I want to see what happens.

What I'd actually love from you

Install it. Publish your first slice, a folder, a project, your weekly reading, your notes from a course, whatever you have lying around. Send me the URL. I'll read it. Maybe we link to each other's notes. If something breaks, tell me. If something feels off, tell me that too.

I built this as a beginning. "Better" is going to come from people who try this and tell me exactly where it cracks.

The Obsidian community plugin store submission is open as PR #12449. While that's in review, install via BRAT (MachoMaheen/brainshare). Source is on GitHub at MachoMaheen/brainshare, MIT-licensed, fork-friendly, contribute-friendly.

Thanks for reading this far. It means more than the analytics will ever show.

Maheen 14 May 2026