Internet Object Playground

An interactive editor for Internet Object — a schema-first, JSON-compatible data format that carries the same data in a fraction of the bytes.

Write a schema, write a document, and watch it parse, validate, and expand into JSON as you type. No install, no signup.

▶ play.internetobject.org

• See the savings. Every document shows how much smaller it is than the equivalent JSON — the example above is 71.95% smaller.
• Convert JSON to IO. Paste any JSON and the playground infers a schema and rewrites it in Internet Object form.
• Separate schema from data. Toggle the schema into its own pane to see how IO keeps structure out of the payload.
• Catch errors as you type. Parse and validation errors are listed as you go; click one to jump straight to it in the editor.
• Share what you build. Any document can be turned into a link that restores the exact editor state.
• Learn from examples. A library of samples covers the basics through to schemas, collections, and edge cases.

It stays responsive on large documents by parsing in a Web Worker, works on mobile, and follows your system's light or dark theme.

The fastest way to understand Internet Object is to see it hold your data.

Hit JSON to IO, paste any JSON object or array, and the playground works out a schema from the shape of your data, then rewrites the document against it — keys lifted out into the schema, values left as a compact positional row. You get back a working Internet Object document and the schema that describes it, ready to edit, plus the size difference against the JSON you started from.

It handles nested objects, arrays, and collections, and infers types (string, number, bool, date) from the values it finds. The feature is marked Experimental: schema inference is a best guess at intent, so treat the result as a strong first draft rather than a finished schema — you will often want to tighten a type, mark a member optional, or name things better.

npm install
npm run dev          # http://localhost:4000

The playground builds against the internet-object library in a sibling folder (../io-js2). To point it somewhere else:

npm run config-io -- ../path/to/library

Note: the library is a local file: dependency, which package managers copy rather than link. After changing the library, rebuild it and re-install here (npm install --force) or the playground will keep bundling the previous copy.

Built with React 19, TypeScript, MUI, Monaco, and Vite. The playground is versioned by publish date (YYYYMMDD), stamped into the build and printed in the browser console.

• Accessibility — WCAG 2.1 AA, keyboard navigation, screen readers
• Web Worker — how background parsing keeps the editor responsive
• Security — audit guidelines, and the quick reference

For the format itself, see the specification.

Copyright © 2019–2026 ManiarTech® (Maniar Technologies).

The Internet Object Playground is licensed under the GNU Affero General Public License v3.0 (AGPL-3.0-only).

You are free to use, study, modify, and self-host it. The one condition: if you run a modified version of the playground and let anyone else use it over a network, you must make your modified source available to those users under the same license. In short — host it freely, but give your changes back.

Note: this copyleft applies to the playground only. The internet-object library itself is separately licensed under the permissive Apache License 2.0, so using Internet Object in your own application places no obligations on you — commercial or closed-source use is fine, and it carries an explicit patent grant.

Internet Object is a trade name and unregistered (common-law) trademark of Maniar Technologies. The AGPL grants rights to the code, not to the name or the logos — so if you publish a fork or host a modified instance, please give it your own name and branding.