Trust & Verification
A verifiable privacy promise. Not our words — your own eyes.
We Cannot Upload Your Data
Not because we promise — because of architecture. DevToolkit Pro has no backend server, no database, no API endpoints. Even if we wanted to upload, there's nowhere to send it.
Technical Architecture
Frontend Layer
React + Web Crypto API. All computation happens in your browser.
Service Worker
Caches all static assets. Every tool keeps working offline.
✗ Backend Server
Does not exist. No Express, no Lambda, no server-side code at all.
✗ Database
Does not exist. There is nowhere your input could be stored.
✗ Input Data Tracking
Your tool input enters no analytics script or server log.
How to Verify (30 seconds)
- 1Open any tool page on this site
- 2Press F12 to open browser DevTools
- 3Switch to the Network panel
- 4Use the tool normally (type text, click buttons)
- 5Observe: the page issues only ad and anonymous-stats requests; your input appears in none of them
Compared to Other Tool Sites
| Feature | DevToolkit Pro | BeJSON | tool.lu | CodeBeautify |
|---|---|---|---|---|
| Data flows to | 100% browser | Server | Server | Server |
| Input data uploaded | Never | Uploaded | Uploaded | Uploaded |
| Works offline | ✅ | ❌ | ❌ | ❌ |
| Tool input tracked | Never | Possibly | Possibly | Possibly |
Mathematical Privacy, Not Legal Privacy
Most websites say "we promise not to upload your data" — that's a legal promise you cannot verify. We say "we cannot upload your data" — that's an architectural fact you can verify yourself.
How This Site Stays Free
To keep the tools free, our pages carry ads (Google AdSense) and anonymous visit statistics (Google Analytics). These requests record page views only — they never contain, and have no access to, anything you type into a tool. All computation runs inside your browser; your input never leaves your device. You can inspect every one of these requests in the DevTools Network panel to verify this yourself.
FAQ
Why is there no AI feature?+
Any AI call requires sending your data to a server, which conflicts with our core "data never leaves your browser" promise. Instead, we use deterministic local algorithms (Schema inference, template libraries, Web Crypto API) to cover most of what AI would do.
How do favorites sync across devices?+
Favorites are stored in your browser's localStorage and never uploaded. You can export a backup from the favorites page and import it on another device.
What happens if your server goes down?+
Nothing. After your first visit, the Service Worker has cached all assets. Even if our servers go down, every tool keeps working.
Are there really no cookies?+
No tracking cookies. Theme and language preferences are stored in localStorage (never uploaded). Verify with uBlock Origin or DevTools → Application panel.