PortableWeb is an open file format for interactive documents. It packages
the HTML, CSS, JavaScript, and media of an experience into a single .pweb file
that runs on any device, fully offline — sandboxed, with no server, no web origin, and
no app store — and still opens years from now. Built by hand, or with any AI tool.
Build me an interactive 3D periodic table.
A web app, treated like a document.
Saved, copied, shared, and run on any platform — fully offline. And as AI models mature, they’ll generate .pweb directly.
The problem
AI-assisted tools have changed the economics of building interactive web content. A simulation, a small game, or a data-rich presentation that used to take days of skilled work is now generated in minutes — by the million. None of it has a natural place to live.
The first question every engineer asks: why not just use what exists?
Requires infrastructure and a live connection. Wrong tool for ephemeral, single-use, or personal content — and it vanishes the day the host goes dark.
Developer accounts, review cycles, ongoing maintenance. Fine for long-lived commercial software; absurd for the volume of artifacts being made today.
Portable and archival, but it flattens everything. A game loop, a live simulation, or a 3D model simply cannot survive the trip.
A ZIP is just files. Nothing says how it’s identified, what runs first, what’s sandboxed, or what a viewer must enforce. PortableWeb is exactly that discipline — built on top of ZIP.
Its scripting is an enhancement to a reading experience, not a general runtime. It can't meaningfully represent a game or a real-time simulation.
Designed as a network transport optimization, not a portable execution environment. No offline-first model; never achieved broad implementation.
Fully interactive, but tied to a live server and a web origin. Installing one doesn’t make it yours — the model says nothing about content that has no server at all.
No existing format treats interactive web content as a portable, self-contained, immediately runnable unit.
The solution
A PortableWeb bundle (.pweb) packages the HTML, CSS, JavaScript, and media
of an interactive experience into one file. A compatible viewer opens it in its
own sandboxed window — on desktop, mobile, or anywhere — entirely offline,
with no deployment, no web origin, and no browser required.
It behaves like a document. You can save it, copy it, email it, archive it, or AirDrop it across the room. It works the first time and the thousandth, and it doesn’t expire when a CDN goes dark.
The format is content-model agnostic: a bundle can hold a game, a presentation, a simulation, a 3D experience, a scientific model, a report, or a book.
Anatomy of a bundle
Rename any .pweb to .zip and unpack it with anything. No proprietary
container, no hidden state, no DRM. Its strength is in discipline, not complexity — a
mimetype marker lets a tool identify a bundle from its first ~80 bytes, exactly
as EPUB does.
application/vnd.portableweb+zip.
Design principles
A bundle carries everything it needs. No CDN dependency. No broken script tags in five years. No surprise network calls. The bundle is the unit of preservation.
No filesystem access, network off by default, storage scoped per bundle. Permissions are declared upfront in the manifest and enforced by the viewer, deny-by-default.
Each spec version freezes a stable subset of the web platform. A v1.0 bundle renders identically in any v1.0 viewer, indefinitely. New features ship in new versions; old bundles never break.
A bundle is a file. No host, no account, no subscription, no platform. You can copy it, archive it, mail it, or seal it in a time capsule. It belongs to whoever holds it.
How it differs
| Format | Interactive? | Offline? | Self-contained? | No server / origin? |
|---|---|---|---|---|
Limited | Yes | Yes | Yes | |
| Webpage / URL | Yes | No | No | No |
| PWA | Yes | After install | No | No |
| EPUB | Partial | Yes | Yes | Yes |
| .pweb | Yes, fully | Always | Yes | Yes |
What it’s for
A real home for the millions of interactive things AI tools create. Stop deploying ephemera; start saving artifacts.
Decks with real interactivity, sent as a file. The natural successor to PDF for anything more than text.
Interactive lessons and simulations that work offline, on any device — and still work next year, and the year after.
Models, visualizations, and reproducible figures that stay explorable — not screenshots of something that used to run.
Journals, calculators, planners, trackers. Tools you keep as files instead of renting as subscriptions.
For libraries, museums, journals, and individuals who need interactive content to outlive any host.
The AI wave
AI tools now generate interactive applications, lessons, simulations, dashboards, and reports in minutes — and most of that work disappears behind a temporary deployment or an expiring share link.
PortableWeb gives AI-generated interactive work a durable, shareable home. The artifact stops being a URL someone else hosts and becomes a file you own.
The format is vendor-neutral: any model or tool that emits HTML, CSS, and JavaScript can
emit a .pweb. As models mature, they’ll produce the finished, portable
file directly — usable everywhere the moment it exists.
Who it’s for
A file format doesn’t pick its users — but a few groups feel the gap today:
Try it now
The PortableWeb app runs entirely in your browser — open and render any
.pweb, pack a project folder into a bundle, validate one against the spec,
or scaffold a new project. No install, no account, and nothing ever leaves your device.
It’s an early-preview reference viewer — here to prove the format
end to end, while native viewers for desktop and mobile are in development.
.pweb anywhere onto the window — it opens sandboxed, full-screen..pweb bundle in one click..pweb or .zip.Install it in Chrome or Edge and .pweb files open on double-click — no browser step.
Standards & openness
PortableWeb isn’t a private format. The container and manifest are specified in an IETF Internet-Draft, and the broader format — sandbox, storage, signing, and a genuinely new offline peer-to-peer channel — is being developed in a W3C Community Group, open to anyone.
Portable Web Content Format CG. Container, manifest, viewer conformance, storage, and inter-bundle communication. Anyone may join.
draft-selvaraj-portableweb-format — the container format, manifest schema, security considerations, and the application/vnd.portableweb+zip media type.
Roadmap
The ZIP layout, the mimetype convention, the manifest schema, the media-type registration. Specified in the IETF draft, with the first example bundles public.
The formal sandbox spec and the frozen subset of HTML/CSS/JS allowed per version. First cross-platform reference viewer.
Per-bundle isolated storage, cryptographic signing, and a permission-gated local channel (Bluetooth, Wi-Fi Direct) for offline multiplayer and collaboration — a capability no existing format has.
From v1.0 forward, bundles render correctly in any v1.0-compatible viewer, forever. New features ship in v1.x and v2.x without breaking old bundles.
Directions under discussion for the ecosystem:
Where the project stands
draft-selvaraj-portableweb-format — the container, manifest, and media type.
Portable Web Content Format CG — open to anyone; no W3C membership required.
Spec (CC-BY 4.0), example bundles, and open-source tooling, all developed in public on GitHub.
Play with .pweb files today: open, pack, validate, and scaffold bundles — entirely in your browser. Open the app.
Reference viewers for desktop and mobile, so a .pweb opens on double-click — no browser step.
FAQ
No. PortableWeb is a file format plus viewers. Viewers use the platform’s existing web engine to render bundles — nobody is shipping a new one.
The container is ZIP, deliberately — like EPUB and DOCX. What makes it a format is the discipline on top: a mimetype marker, a manifest, a defined entry point, and sandbox rules every viewer must enforce.
No. Bundles are fully self-contained and run offline. Network access is off by default, and only possible if declared in the manifest and granted by the user.
No. There is no filesystem access, storage is isolated per bundle, and all permissions are deny-by-default and enforced by the viewer.
Yes. Any HTML, CSS, and JavaScript works. Add a manifest.json, zip it per the spec — or point the web app’s Pack tool at your project folder.
Yes — full scripting, inside the sandbox. Real interactivity is the whole point of the format.
Yes. The specification is CC-BY 4.0, the tooling is MIT, and everything is developed in public at the IETF, the W3C, and on GitHub.
Yes. The format is vendor-neutral — any model or tool that emits web content can produce a bundle, and the spec is written so models can eventually emit .pweb directly.
Get involved
Whether you’re a developer, educator, researcher, archivist, AI builder, or standards contributor — the spec is young, and your ideas can shape PortableWeb from the beginning.