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jsonforge.app

About jsonforge.app

Last updated: September 2026

jsonforge.app (https://jsonforge.app) is an independent project: a focused set of free, browser-based tools for working with JSON and the formats that surround it. It grew out of a simple frustration — needing to quickly format, inspect, or convert a chunk of JSON, and having to choose between a bloated online "toolbox" that wanted an account, a desktop app to install, or pasting production data into a site that quietly POSTs it to a server. None of those felt right for something as routine as pretty-printing an API response.

So jsonforge.app is deliberately narrow. Each tool does one job — a formatter, a visual tree explorer, a table / CSV / Excel converter, a repair tool for broken JSON, an escape / unescape utility, JSON↔XML and JSON↔YAML converters, a diff / compare view, a visual editor, an inspector for stats and duplicate keys, a fake-data generator, a placeholder-image and placeholder-API service, code generators for a dozen languages (TypeScript, Go, Rust, Python, Java, Kotlin, C#, PHP, and more), and a visualizer for Google Maps Timeline exports. There is no dashboard, no project concept, and nothing to configure.

There's a second reason the toolset looks the way it does: a lot of it grew out of testing real applications. The fake-data generator, the placeholder API, and the placeholder-image service exist because building or testing an app usually means you need a believable user object, a working endpoint, or a stand-in image before the real backend is ready — and reaching for a full mocking framework for that is overkill. These tools are the shortcuts that testing kept demanding, cleaned up and made public.

Everything runs in your browser

Most JSON tools online ask you to paste sensitive data — API responses, auth tokens, config files, customer records — into a form that gets sent to a server somewhere. jsonforge.app doesn't do that. Every tool runs entirely in your browser using JavaScript's built-in JSON parser and client-side libraries. The site is a static front end backed by a small edge function layer that only ever serves the placeholder API and generated images; there is no endpoint that accepts the JSON you paste in, no database, and no logging of tool input. Nothing you paste is uploaded, logged, or stored by us — not as a policy choice we could reverse, but because no server-side code path to do it exists.

A practical consequence: the tools keep working with your network disconnected, they're safe to use on data you're under contract not to share, and the only third-party requests a tool page makes are for map tiles (on the Timeline visualizer, and only for the provider you pick) and, once the site is approved for it, display ads.

How the tools are built

  • One shared page shell wraps every tool, so each one ships with the same breadcrumb, structured data, keyboard support, and light/dark theming — no tool can regress those.
  • Every tool page carries hand-written documentation: what the tool is for, step-by-step usage, worked examples, common mistakes, and an FAQ. That text is specific to each tool, not spun boilerplate.
  • The parsing and conversion logic is unit-tested, and the interface is fully localized into English, Spanish, French, Portuguese, and Indonesian.
  • A companion Chrome extension, "JSON Viewer by jsonforge.app", formats raw JSON responses in the browser tab itself. It follows the same rule as the site — all formatting is local, and it transmits nothing.

What we believe

  • Developer tools should be fast, free, and not require an account.
  • Your data is your data — a formatter doesn't need to see it to format it.
  • A tool that does one thing well beats a bloated do-everything dashboard.
  • Documentation is part of the tool, not an afterthought.

How this site is funded

jsonforge.app is free to use and funded by unobtrusive display advertising. We don't sell your data (we don't have any of it to sell), ads are kept out of the tools' working area, and ad placement never comes before the tools working correctly. See our Privacy Policy for details on how ads and cookies work here, and our Terms of Service for the terms that apply when you use the site. If you'd like a deeper background on the format itself, the blog has long-form guides on JSON, JSON Schema, API design, and related topics.

Who's behind this

jsonforge.app is built and maintained by Robioki Denis, Founder & Engineer. GitHub · LinkedIn · Instagram.

Get in touch

Found a bug, hit a Timeline or export file the parser choked on, want a new tool or an existing one improved, or have a business inquiry? Email hello@jsonforge.app — a short description of what you were doing and, where you can share it, a sample input is enough to act on. Tool requests are genuinely welcome; several of the converters here started as one.