Devkit
Live: JSON, JWT, Base64, URL, Regex & Color tools

A modern toolbelt for developers.

Format JSON, decode JWT tokens, encode Base64 and URLs, test regex, convert colors, and more — a dozen everyday utilities in one polished app. Free forever, private by default, with every tool running locally in your browser.

JSON FormatterJWT DecoderBase64 StudioURL EncoderRegex TesterColor StudioBrowse all tools
No sign-up100% client-side
json-formatter
{"name":"Aurora",
"version":"2.4.1",
"active":true,
"tags":["fast","tiny"]}
"name": "Aurora",
"version": "2.4.1",
"active": true,
"tags": [
  "fast",
  "tiny"
]
Valid JSON4 ln · 89 ch
12 tools and counting

One toolbelt for every small developer task.

Beautifully crafted utilities for the things you do every day. Free, fast, and respectful of your data.

Live

JSON Formatter

Format, validate, and beautify JSON side-by-side.

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Live

JWT Decoder

Inspect headers, payloads, and signatures in real time.

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Live

Base64 Studio

Encode or decode text and small files instantly.

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Live

URL Encoder

Percent-encode and decode URL text with component or URI mode.

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Live

Regex Tester

Test patterns with live highlights and capture groups.

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Live

Color Studio

Convert between HEX, RGB, HSL, and OKLCH.

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Soon

UUID Generator

Bulk-generate v4 / v7 UUIDs with copy & download.

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Soon

SQL Formatter

Pretty-print SELECT, JOIN, CTE and more.

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Soon

YAML ↔ JSON

Round-trip convert between YAML and JSON.

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Soon

Markdown Preview

Live render with GitHub-flavored syntax.

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Soon

Diff Checker

Side-by-side text and JSON diff with sync scroll.

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Soon

Cron Helper

Build and explain cron schedules in plain English.

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Runs in your browser

No data ever leaves your device. Every tool works offline-first.

Built for speed

Instant formatting, parsing and conversion — no spinners, no waits.

Consistent design

One coherent UI, keyboard friendly, light & dark themes everywhere.

Free online developer tools — private by default

Devkit bundles the utilities developers reach for dozens of times a day: format and validate JSON, decode JWT tokens to inspect claims, encode or decode Base64 text, percent-encode URLs, test regex, and convert HEX, RGB, HSL, and OKLCH — without installing extensions or creating accounts.

Every tool is 100% client-side. Your payloads never leave the browser, which makes Devkit suitable for API responses, auth tokens, config files, and production debugging.

Live tools

Frequently asked questions

What is Devkit?

Devkit is a free collection of browser-based developer tools — including a JSON formatter, JWT decoder, Base64 encoder, URL encoder, regex tester, and color studio. Every tool runs locally in your browser so your data stays private.

Is Devkit free to use?

Yes. All tools are free with no signup, no rate limits, and no ads. You can use them as often as you need for work or personal projects.

Does Devkit upload my data?

No. Formatting, decoding, and encoding happen entirely on your device. JSON, JWTs, and Base64 payloads are never sent to a server.

Which tools are available right now?

JSON Formatter, JWT Decoder, Base64 Studio, URL Encoder, Regex Tester, and Color Studio are live today. More utilities — UUID generator, SQL formatter, YAML converter, and others — are on the roadmap.

Can I use Devkit offline?

After the page loads once, most tools continue to work offline because processing is client-side. You need an internet connection only for the initial visit.

How is Devkit different from other online formatters?

Devkit combines multiple everyday utilities in one consistent interface with dark mode, keyboard-friendly controls, and a privacy-first architecture — no accounts and no server-side processing.

How do I percent-encode a URL or query string?

Open the URL Encoder tool, paste your plain text, and choose Component mode for encodeURIComponent (query values) or URI mode for encodeURI (full URLs). Copy the encoded output for fetch calls, redirects, or API links.