Offline developer tools that never leave your machine.
A JSON formatter, Base64 encoder/decoder, regex tester, JWT decoder and epoch converter — all in one popover, 100% offline. Nothing you paste ever leaves your machine.
{
"id": 7,
"tags": ["a", "b"]
} Five tools, one popover.
Open the Dev tools widget and switch between tabs: paste JSON to prettify or minify it, encode/decode Base64, decode a JWT into its header and payload, test a regex against sample text, or convert an epoch/Unix timestamp to a readable date. No context switch, no browser tab.
- JSON formatter — prettify & minify
- Base64 encoder/decoder and epoch/timestamp converter
- Lives in the same menu-bar icon as the rest of Toolbox
{
"alg": "HS256"
}
{
"sub": "7",
"role": "admin"
} Sensitive payloads stay on your machine.
Pasting a JWT, an API response or a config blob into a random online formatter means handing that data to someone else’s server. Dev Tools runs entirely locally — every tool works with no network calls, so your tokens and JSON never leave your computer.
- 100% offline — no server, no network calls
- Your JWTs and JSON stay on your machine
- In your menu bar, alongside the rest of Toolbox
The everyday utilities, in Toolbox.
If you’ve used DevToys, Boop or a pile of online formatters, this covers the day-to-day — JSON, Base64, JWT, regex and epoch — without pasting sensitive data into a website or juggling another standalone app. It rides along inside Toolbox, so it’s one menu-bar icon for your dev tools, notes, timers and clipboard.
- A free DevToys / Boop alternative
- Cross-platform, offline, no account
- Part of a whole toolbox, not a lone icon
d2Vic3RhcnRlZA==
Questions, answered.
Which tools are included?
A tabbed panel of everyday developer utilities: a JSON formatter (prettify & minify), a Base64 encoder/decoder, a regex tester, a JWT decoder, and an epoch/Unix-timestamp converter — all in one popover.
Does it work offline? Is my data sent anywhere?
Everything runs 100% locally, on your machine. Nothing is sent to any server — no network calls. That’s the point: pasting a sensitive JWT or JSON payload into a random website is a privacy risk, so these tools process it right where you are.
Can it decode JWTs and test regex?
Yes. The JWT decoder splits a token into its header and payload so you can read the claims, and the regex tester lets you check a pattern against sample text as you type — both offline.
Is it free?
Yes. Dev Tools is one of the widgets built into Webstarted Toolbox, which is free to download and use — no account required.
Does the JWT decoder verify the signature?
No — it decodes. It splits the token, shows the header and payload, and surfaces the time claims (exp, iat, nbf), but it does not check the signature (that needs the secret or public key). Use it to inspect a token, not to trust it as authentication.
macOS and Windows?
Both. It’s the same app on macOS 12+ and Windows 10+, so your dev tools live in the same menu-bar icon on either platform.
Get Webstarted Toolbox
Free to use. Dev Tools and every other widget included. macOS 12+ and Windows 10+.
One icon, many small tools
This is just one of the widgets in Webstarted Toolbox. Here are the rest: