Hand it over. It gets signed. It's yours. Upload anything and get one proper
document you fully control — no PDF headache, no DocuSign, no subscription.
HTML is the sweet spot: open, simple, yours.
SHA-256 sealed · Ed25519 verifiable · nothing leaves your device
Agreement
I
The idea
One format that just works — everywhere, forever.
PDFs fight you. Word locks you in. HTML is the open, universal, signable middle: it opens on every device, weighs nothing, and you hold the whole file.
01
Proper documents
An algorithmic engine cleans any upload into real semantic HTML — headings, lists, tables, the Momentum document look. Not a screenshot of a page. A document.
02
You sign. You own.
Sign in your browser and download a single self-contained file with a SHA-256 integrity seal. No account, no service, no one between you and your document.
03
Nothing leaves the device
Conversion and signing run entirely in your browser. Your file is never uploaded. Complete control isn't a feature here — it's the architecture.
II
Why HTML
Why trust HTML as a document?
A document should outlive the app that made it, open on anything, and be
something you can actually read and check yourself. That is HTML — not a web page,
the document itself, in the open.
You can read it yourself
It's plain text. Open it in any editor and the whole document is right there — no binary blob, nothing hidden, nothing that needs one specific app to decode.
No owner. No lock-in.
HTML is an open standard that belongs to no company. A .docx needs Microsoft, a PDF needs Adobe. HTML outlives any vendor — and any subscription.
Opens everywhere — still will in 30 years
Every device with a browser reads it. An HTML file from decades ago still opens perfectly today. That is what durable actually means.
One file carries everything
Text, layout, structure, signature and integrity seal — all in a single self-contained file. You don't need the program that made it. The document stands on its own.
Proof, not trust-me
Because it's open, anyone can independently recompute the SHA-256 hash and verify the Ed25519 signature. You trust the math, not a logo.
It's what everything already runs on
Email, apps, and AI agents are all HTML underneath. Make the document HTML and it drops straight into the systems — and the agents — that already exist.
The web made HTML universal. The next step is everything else — documents,
contracts, records — built on the same open foundation. One format you can read, own,
and prove. That is the future Momentum Simplicity is built for.
III
Convert & sign
Drop a file in. Get a document out.
Supports .docx, .md, .html, .txt, .csv, .xlsx, .ods, .odt, .rtf and .pptx — one file or many. It converts in front of you: no upload, no wait. You can also just paste text with Ctrl+V.
1Your document
Converted locally in your browser.
Drop files or clickTap to open a document.docx · .md · .html · .txt · .csv · .xlsx · .ods · .odt · .rtf · .pptxYour file never leaves this device — or paste text with Ctrl+VYour file never leaves this device
Momentum Velocity — our own model — reads the document and answers. This one sends the document's text to Momentum's AI (the read above stays on your device). Nothing is stored.
Live document previewsealed
Your document appears here
Drop a document on the left — it appears here, clean and signable.
Momentum converts it into clean, semantic HTML — the same document you'll download. Sign it if you like; the signature and a tamper-evident seal are baked right in.
IV
The real target
Built for AI agents first.
Every AI module that needs to read, produce or sign a document can pull it through one clean engine. Same pipeline as this page — callable, deterministic, safe-by-default. Vibecoding gets documents for free.
→
One engine, two doors
The website and the agent API share the exact conversion + sanitize + seal pipeline. What you see here is the same thing an agent calls.
→
Safe by default
Untrusted documents become HTML with every script and handler stripped at the gate. Agents can convert hostile input without converting hostile behaviour.
⌁
The gated line
Free for humans, metered for machines. The agent/API tier is the income line — wired through one choke point, verified by the Momentum License Service.
V
Pricing
Free for people. A license for machines.
The whole app — convert, edit, sign, own — is free in your browser, forever. The paid line is the metered agent API: the same engine, called by your automations. No account, no lock-in; a license is a cryptographic token you hold.
Free
£0 · forever
Everything, in your browser. Your files never leave the device.
For people who want white-label exports and to back the project.
Everything in Free
White-label exports — your document, no generator tag
Priority on new features
One license, verified by cryptography — no account
The income line
API · Agent
—
The /api/convert endpoint — every automation pulls documents through one clean, safe engine.
Everything in Pro
Programmatic POST /api/convert → clean, sealed HTML
Higher rate & volume limits
Authenticate with x-momentum-license — no forgeable key
Have a license?
Paste your Momentum license token to activate it on this device. It is verified locally, with cryptography — the token never leaves your browser.
API quickstart — convert a document from code
curl -X POST https://momentum-simplicity.vercel.app/api/convert \
-H "content-type: application/json" \
-H "x-momentum-license: <your license token>" \
-d '{"filename":"contract.docx","contentBase64":"<base64 of the file>","sign":true}'
Returns clean, sanitised HTML (plus a SHA-256 seal when sign:true). Untrusted input is stripped at the same fail-closed gate the browser uses — one engine, two doors. The endpoint is dark until switched on for launch.