I just wanted to sketch a database schema. Five tables, a couple of foreign keys, nothing fancy.

I opened the usual suspects, and every single one met me with the same wall: create an account, confirm your email, maybe pick a plan, then you can draw a box. For a thirty-second sketch.

So I did the most predictable developer thing imaginable and built my own. It's live at erdiagram.dev — free, and you can start drawing the moment the page loads. No signup, no modal, nothing in the way.

This is the why , plus the three technical decisions I'd actually defend in a code review:

The browser is the backend for guests (so there's no signup wall).

Canvas instead of DOM/SVG for the renderer.

A boring last-write-wins sync protocol instead of CRDTs.

Let's get into it.

1. The one rule: it has to work before you have an account

The whole project hangs on a single principle: the editor works before you sign up.

That sounds trivial, but it shaped a surprising amount of the architecture.…