Most JSON tools are built around one file at a time. That fits about half the jobs we actually do. The other half — and arguably the harder half — is about comparing JSON: two API responses, three config files, ten logs. That's where Jsonize's multi-file tab system quietly becomes the most useful feature on the page.

How the tabs work

When you open or drop more than one file, Jsonize renders a tab bar above the viewer. Each tab is one JSON document. Click to switch, hit the x on a tab to close it, or use Clear All to reset. Each tab remembers its own search query, its expand/collapse state, and whether you're in card view or code view. Switching tabs is instant.

The Load More button lets you add additional files at any time, keeping the existing ones. That sounds trivial until you realize how often you end up wanting to add a fourth file halfway through a debugging session.

Workflow 1: Comparing API responses

You're debugging why a frontend started misbehaving. You suspect the response shape changed. You curl the endpoint in staging and prod, save each as a .json, drop both into Jsonize, and flip between tabs. The same field is right there in the same position in both views — your eye immediately catches what's different.

With pretty formatting and per-tab search, this takes about 30 seconds. Doing it in a pair of IDE tabs usually takes longer because you're fighting with formatting, word wrap, and syntax coloring.

Workflow 2: Diffing configs across environments

Open config.dev.json, config.staging.json, and config.prod.json in three tabs. Use the same search in each ("database", "rateLimit", "featureFlag") and spot-check how values drift. This is a surprisingly common source of production incidents — a flag that's on in staging but off in prod, a timeout that's 30s here and 5s there.

Workflow 3: Hunting through a batch of logs

Structured JSON logs (one object per line) usually get dumped into a folder during an incident. You can load several of them into Jsonize at once, scan for the correlation ID in each tab, and piece together the story without bouncing between text editors. The Code View mode is especially handy here — it preserves the structure while staying compact enough to scroll through quickly.

Workflow 4: Reviewing fixtures and seed data

Test fixtures live or die by consistency. Open every fixture involved in a failing test in its own tab, flip through them, and check that IDs line up, references resolve, and shape matches. You don't need to check out a branch or fire up your editor — just drag and drop.

Workflow 5: Handing off a review

You've prepared three example payloads for a colleague's review. Share a link to Jsonize, tell them to drop all three in, and describe the differences. No back-and-forth uploads, no screenshots, no worry about what service holds the data — because there's no service.

Tips that make this much faster

• Drop multiple files at once. The upload area accepts multi-selects from your OS file picker and multi-file drag-and-drop. No need to load them one by one.
• Name your files. The tab label is the filename. prod-user.json beats data (3).json every time.
• Per-tab search. Each tab's search box filters just that tab. Makes it trivial to answer "is this key in both files?"
• Expand / Collapse All. The Ctrl/Cmd + E and Ctrl/Cmd + W shortcuts work per tab — great for normalizing your view before comparing.
• Close what you don't need. The tab bar stays compact, but big payloads do use memory. Close old tabs when a session gets heavy.

Underrated feature: Everything in multi-file mode is still entirely client-side. You can open a dozen files full of production data with zero concern about where they're going.

The bigger point

"One JSON at a time" is a UX default, not a law of nature. Most real debugging is comparative, and the tools that make comparison cheap pay for themselves in minutes. Jsonize's tabs exist because juggling tabs in your browser's address bar, or hopping between IDE windows, is the kind of friction that slowly grinds a workday down. A single page with real tab support fixes that.