Every tool you need,not one you don't.Free at the core.
Developer tools for JSON, PDF, regex, images, colors, and encoding — all running in your browser. No sign-up, no uploads, nothing leaves your machine.
Proof, not promises.
This JWT decoder runs entirely in your browser. Open your network tab — zero requests, every time.
{
"alg": "HS256",
"typ": "JWT"
}{
"iss": "devtoolbox.app",
"sub": "devtoolbox",
"name": "DevToolbox",
"tagline": "Privacy-first developer utilities, 100% client-side",
"tools": [
"json-formatter",
"jwt-decoder",
"base64",
"regex-tester",
"color-converter"
],
"role": "developer",
"iat": 1730864000,
"exp": 1730950400
}Explore by category
13 categories · 31 tools
Good tools get out of your way. Ours stay private, fast, and free.
No accounts, no uploads, no upsells — every tool runs on your machine, and nothing you touch ever leaves it.
— built quietly
The non-negotiables.
No servers in the loop — just fast, private tools that respect your data and your keyboard.
Private by default
Everything runs in your browser. There's no server to send your data to in the first place.
Instant
No uploads, no queues. Every tool runs at native speed the moment the page loads.
Keyboard-first
⌘K reaches any tool. Built for hands that would rather stay on the keyboard.
Works offline
Once a tool has loaded it keeps working — no connection required.
Questions,
answered
The short version: it's private, free, and yours to use. Still curious? The fastest answer is to open a tool and watch your network tab.
Browse all tools01Is my data private?
Yes. Every tool runs entirely in your browser. Nothing you paste, type, or upload is sent to a server — there is no server processing your content.
02Is it really free?
Yes. All 20 tools currently shipped are $0 — no trials, no credit card, no usage caps. Future heavier tools may sit behind a paid tier, but anything live today is open to use.
03Do I need an account?
No. There is no sign-up, no email wall, and no login. Open a tool and use it immediately.
04Does it work offline?
Once a tool's page has loaded it runs locally, so most tools keep working without a connection. Some heavier tools download a one-time module on first use.
05Can I use it for sensitive data?
Because processing is client-side and nothing is transmitted, these tools are well-suited to data you would not want to paste into a hosted service. Always follow your own organisation's policy.
Pick a tool. Get to work.
31 handcrafted developer utilities — free, private, and running entirely in your browser.