jsonsql.dev 100% client-side
← Back to tools

About jsonsql.dev

Who built jsonsql.dev?

Hi, I'm Son Nguyen, a software developer from Vietnam with over 10 years of experience building web applications. I built jsonsql.dev because I was tired of existing JSON tools that upload your data to servers, show intrusive ads, or lack the features I actually need.

Throughout my career working with APIs, microservices, and data pipelines, I've used dozens of online JSON tools. Most of them share the same problems: they send your data to a remote server for processing, they're cluttered with ads, and they only do one thing. I wanted a single, fast, private toolkit that covers every common JSON and developer task — so I built one.

Why is privacy important for developer tools?

Developers routinely paste sensitive data into online tools — API responses containing user PII, JWTs with auth tokens, configuration files with secrets. jsonsql.dev processes 0 bytes of user data on its servers. Every tool runs 100% in your browser using JavaScript. There is no backend, no API calls, no data collection. Your JSON, your JWTs, your Base64 strings — they never leave your machine.

This isn't just a privacy feature — it's a security requirement. When you paste a JWT into an online decoder, you're trusting that service with your authentication token. With jsonsql.dev, that trust is unnecessary because the data never leaves your browser.

What makes jsonsql.dev different?

jsonsql.dev offers 19 free tools across JSON manipulation and developer utilities — all in one place, all client-side. Here's what sets it apart:

  • 0 bytes uploaded — all processing happens in your browser, no server round-trips
  • 0 cookies set — no tracking, no analytics, no fingerprinting
  • 0 accounts required — open a tool and use it, no sign-up walls
  • 19 tools — JSON formatter, viewer, validator, converter, differ, query engine, schema generator, path finder, JWT decoder, Base64, URL encoder, hash generator, UUID generator, regex tester, and more
  • 3 query syntaxes — the flagship JSON Query tool combines JSONPath, SQL, and MongoDB query in one interface (no other online tool does this)

How does jsonsql.dev work?

jsonsql.dev is a static site built with Astro for server-side generation and Vue 3 for interactive tool components. When you visit a page, the HTML is already pre-rendered for fast loading and SEO. The interactive tool UI loads as a Vue component in your browser.

All data processing uses browser-native JavaScript APIs and well-tested open-source libraries:

  • Astro — static site generation, pre-rendered HTML for every page
  • Vue 3 — reactive interactive tool components
  • CodeMirror 6 — syntax-highlighted code editors with line numbers
  • Cloudflare Pages — global CDN hosting, no origin server

Because the site is served as static files from Cloudflare's global CDN, there is no application server that could receive or store your data. The architecture makes data collection physically impossible — not just a policy choice.

The flagship: JSON Query

jsonsql.dev is the only online tool that combines JSONPath, SQL, and MongoDB query syntax in one interface. No other site offers all three. Pick the syntax you know, paste your JSON, and get results instantly. Each syntax has its own dedicated sub-page with documentation, examples, and syntax references.

Page authored by Son Nguyen — last updated: April 2026