The people spoke. We listened. You can now copy JSON from fknjsn.

Source: Dev.to

When I launched fknjsn.com — a local‑first JSON comparison tool with no backend, no tracking, and a name your mum wouldn’t approve of — I expected maybe twelve people to use it. Mostly me. Possibly my future self debugging the same API at 2 am.

Instead, something unexpected happened. People from 15 countries started showing up:

Australia, United States, Netherlands, India, United Kingdom, Poland, Germany, Spain, Pakistan, Guatemala, Hong Kong, Romania, Italy, Singapore, Saudi Arabia.

A truly global coalition of developers who are tired of pasting secrets into online formatters and hoping for the best. And they all wanted the same thing.

“Let me copy the damn JSON”

You could paste JSON in, format it, filter it, compare two payloads side by side—all without a single byte leaving your browser. But when you wanted to actually take the result with you, you were selecting text like an animal.

Developers from across four continents were independently arriving at the same frustration, which honestly felt like a UN resolution against bad clipboard UX.

What’s new

You can now copy filtered and formatted JSON with one click. That’s it. That’s the feature.

• Filter a nested payload down to the three keys you care about → copy
• Format some minified nightmare into something readable → copy
• Compare two responses, find the diff, grab the clean version → copy

It respects whatever state your JSON is in. If you’ve filtered it, you get the filtered result. If you’ve formatted it, you get the formatted output. Not the original. Not some re‑serialized approximation. What you see is what you copy.

paste → format → filter → copy → done → go outside

Revolutionary stuff. Also known as “finishing the job.”

Still no backend

Same architecture as before. Your JSON never leaves your browser. No server. No database. No shareable URLs that attackers can scrape. No save feature that quietly publishes your AWS credentials to a guessable endpoint for five years.

Just localStorage, a copy button, and the basic respect of not uploading your data to someone else’s computer.

Try it

fknjsn.com — paste, format, filter, copy. Everything stays local.

The source is still a single HTML file. View source still works. The trust model is still “don’t trust me, verify it yourself.”

Now with 100 % more clipboard support, by popular international demand.

The name is pronounced exactly how you think it is. And apparently, developers in 15 countries all think the same thing.