That online JSON converter you paste prod data into? It's uploading it.

We've all done it. You've got a chunk of JSON — an API response, a config file, a database export — and you need it as YAML or CSV right now. So you Google "json to yaml", click the first result, paste your data in, and copy the output.

Here's the uncomfortable part: a lot of those converters POST your input to a backend. Open the Network tab next time — you'll often see your payload flying off to a server you know nothing about. If that JSON contained an API key, a customer email, or an internal hostname, it just left your machine.

Let's fix that. Here are ways to convert data formats without uploading anything.

Option 1: Do it in code (Node / browser)

If it's a one-off and you already have a terminal open, you rarely need a website at all.