Open NoteOne endless sheet of paper in your browser. Ink, code, molecules, spreadsheets, circuits — all on the same sheet, all staying on your machine.
the sheet keeps going →
double-click it: it writes
in the app, click the rail
and the sheet grows ↘
Draw real molecules
Draw on it. The pen rail is on the left; type n, o, cl to change element. Or press ⌕ and ask for anything — the formula, mass and name under the drawing are worked out live.
The > edge slides the live 3D companion open beside the drawing — drag it to spin, scroll to zoom, click two atoms for the distance, three for the angle, four for the twist. ⇩ exports transparent SVG / PNG artwork or copies ChemFig LaTeX; ✎ holds the size slider, labels, lone pairs. Every line of it is the app’s own code.
Flick a switch — watch the ones arrive
A half adder, running. Click the switches. Drag a lead out of any port. Drag new gates in from the rail.
⌕ inspects a component — its truth table lights the row it is standing on, and a custom gate’s table is yours to fill in. ▦ swaps in a full adder, a multiplexer, flip‑flops with a running clock. Wire a loop and the gates say so rather than pretending.
A terminal
on the paper
Twelve languages, coloured the way your editor colours them — and the cell below is the app’s own editor, so write in it: brackets close themselves, Enter keeps the indent, ⇥ and ⇧⇥ move whole blocks.
Six colour schemes. The default mixes its terminal out of the note’s
own ink and paper — flip this site’s theme and watch it follow.
```fences``` inside any text box get the same treatment.
The page does
the maths
Coordinate systems you draw in — functions like sin(2x)/x compiled by hand
(nothing is ever eval’d), vectors you pull out of the paper,
and matrices you throw at them: drop one on the plane and the basis walks in
from the identity while you watch. LaTeX between $$…$$ typesets itself,
no library at all.
Drop a spreadsheet
on the paper
A real .xlsx, .ods or .csv lands as a table — a workbook is a zip of XML
and the browser already has an unzipper, so no parser is vendored in. Cells take
=SUM(A2:B4); wire columns through nodes to scale and transform
them; drop the table on a coordinate system and it plots. And for numbers you want to
show: the legend under the chart is the editor. Try it.
Draw over
everything
Ink goes wherever you drag — over pictures, tables and plots alike, the pen thickening where you slow down like a real nib. And when you’re drawing form, wireframe guides — cube, sphere, torus — are construction lines to put your pen on top of, the far side dashed the way you’d build through a form on paper.
Wall charts that work
Logic circuits
Gates, flip-flops, a clock — no run button, the ones just run. There’s one working further up ↑
Chart of nuclides
All 3,558 nuclides from NUBASE2020, neutrons across, protons up. Press one for its half-life, branches, Q‑values — and the chain walked down to lead.
Periodic table
The reference card, on the page — tap an element for its mass, electronegativity and electron configuration, written along the foot.
FITS files
An astronomy .fits opens to its headers without reading the data — a 4 GB cube opens like a small one. Drag a table’s columns out and plot them.
Also on the shelves: five text styles, checklists, flip cards, stickies · pictures, video, .obj models, .pptx decks, attachments and folders · five wireframe solids · washi tape and stickers — every one of them drags, rotates, takes ink, prints, and travels in a backup.
Ask yourself, on index cards
Question on the front, answer on the back — cards are little boards, so equations, pictures and even live 3D land on them. Multiple choice marks itself. This deck is about the app — study it.
Leave with everything
There is no server to trust. The app is a folder; your notes live on your machine; and three doors are always open:
Export one .html
The whole note as one self‑contained page — flip cards that still turn with no script at all, videos riding inside. Send it to anyone, publish it anywhere.
Print / PDF
Through the browser’s own print dialog — equations, plots, molecules and working, exactly as they stand on the paper.
Back up / restore
The whole note — models, videos, attachments and all — as one .json snapshot you keep. Restore it on any machine and carry on.
No dependencies. No build.
No kidding.
Double‑clicking index.html has to open a working app — that
rule shaped everything underneath. No bundler, no npm, no frameworks; classic scripts whose
load order is the dependency graph.
One feature, one file
A feature’s markup, behaviour, toolbar, palette tile and stylesheet live together
in one file, and it announces itself with defineItem(). Nothing in the core
knows what a molecule or a plot is — it asks the registry. Adding a feature touches
two files: the new one, and one script line.
Hand‑rolled, on principle
- LaTeX typeset by 460 lines compiling to MathML — no library, nothing downloaded.
- A molecule is a small graph: SMILES, layout, 3D and VSEPR in ~1,000 lines that touch no DOM.
- The chart of nuclides is one table of masses — every Q‑value is subtraction, done as you press.
- Eigenvalues by Hessenberg + shifted QR; formulas share a hand‑written compiler — nothing is ever
eval’d. - A harness drives the app in headless Firefox — 1,805 assertions, plus 45 driving the real desktop shell.
The honest answers
Where does my work live?
On your machine — in the browser’s own storage, saved automatically as you work.
Back up gives you the whole note as one .json you keep; Restore
brings it back anywhere. Do it regularly if the note matters to you.
Does it need the internet?
No. It’s a folder — double‑click index.html, serve it, or use the
desktop app. Nothing you make is ever sent anywhere.
Is there a desktop app?
Yes — alpha builds for Linux, Windows and macOS on GitHub Releases. They are unsigned, so your OS will warn once; if that bothers you, build it from source — it is the same code.
Is it open source?
Yes — github.com/AlessioPop/open-note. The name was the hint.
Where do questions go?
opennotemail@gmail.com — or open an issue on GitHub.
Start a note
It opens in your browser, it works on your desk, and it’s already yours.
It’s just a folder — host it anywhere, or double‑click
index.html at home. Same app either way.