Every Deresaw tool does its work inside your browser. The text you type and the photos and PDFs you add are processed on your own device and are not uploaded to us or anyone else. This page explains how that works, how we test it, and how you can check it yourself.
Last tested: 10 October 2026. Result: 68 of 68 tools sent nothing you entered or uploaded.
How it works
A normal website sends your file to its server, processes it there and sends the result back. Our tools are written in JavaScript that runs in the page itself, so the work happens on your computer or phone. Converting a photo, merging PDFs, decoding a token or running a loan calculation needs no server at all.
Some tools need a bigger piece of code, such as the open-source pdf-lib and PDF.js libraries for PDFs. Those are downloaded from cdnjs, a public code library, when the page opens: the same file for every visitor, requested before you add anything. Your files are never part of that request. The Currency Converter downloads the day’s exchange rates in the same way; the amounts you convert are not sent.
Nothing is saved, except in one tool: the Invoice Generator keeps your last draft and logo in your browser’s local storage so you can come back to them. That copy stays on your device, and the Clear button removes it.
How we test
A privacy claim is only worth something if it is checked, so we test every tool and record the result. We open each tool on its own in a Chromium browser with network logging on. We type sample text into every field, add generated test files (a JPEG, a PNG and a three-page PDF) to every upload box, and click every button except Clear, Remove and Print. Then we list every network request made after the page finished loading. A tool passes only if it made no request at all after loading. Tools that pass show “Tested” on their page. A new tool keeps a plain privacy note until it has been through the same test.
Check it yourself
- Open a tool and let the page finish loading.
- Open your browser’s developer tools (F12, or Ctrl+Shift+I; on a Mac, Cmd+Option+I) and choose the Network tab.
- Click the clear button in the Network tab so the list is empty, then use the tool: type, add a file, convert, download.
- Watch the list. Requests from the tool would appear there. You may still see requests from the advertising on the page (see below), but none of them carries your file.
An even simpler test: once a tool page has loaded, turn off Wi-Fi or mobile data and use it. Everything except the Currency Converter keeps working offline.
What else runs on the page
The site is free because it shows Google ads. Like most websites, the page loads Google’s advertising scripts, which make their own requests and may use cookies; you can see them in the Network tab. Our tools never pass what you type or upload to them. Our privacy policy explains the advertising and your choices.
Every tool, tested
🧮 Calculators
| Tool | Sends what you enter? | Loads from the internet | Saved in your browser |
|---|---|---|---|
| Age Calculator | ✅ No | Nothing | Nothing |
| BMI Calculator | ✅ No | Nothing | Nothing |
| Date Calculator | ✅ No | Nothing | Nothing |
| Discount Calculator | ✅ No | Nothing | Nothing |
| GPA Calculator | ✅ No | Nothing | Nothing |
| Loan Calculator | ✅ No | Nothing | Nothing |
| Percentage Calculator | ✅ No | Nothing | Nothing |
| Time Card Calculator | ✅ No | Nothing | Nothing |
| Tip Calculator | ✅ No | Nothing | Nothing |
💰 Finance
| Tool | Sends what you enter? | Loads from the internet | Saved in your browser |
|---|---|---|---|
| Car Loan Payoff Calculator | ✅ No | Nothing | Nothing |
| Coast FIRE Calculator | ✅ No | Nothing | Nothing |
| Compound Interest Calculator | ✅ No | Nothing | Nothing |
| Debt Snowball vs Avalanche Calculator | ✅ No | Nothing | Nothing |
| Hourly to Salary Calculator | ✅ No | Nothing | Nothing |
| Investment Fee Calculator | ✅ No | Nothing | Nothing |
| Invoice Generator | ✅ No | pdf-lib (code) | Your draft, on this device only |
| Loan Comparison Calculator | ✅ No | Nothing | Nothing |
| Markup vs Margin Calculator | ✅ No | Nothing | Nothing |
| Mortgage Calculator | ✅ No | Nothing | Nothing |
| Mortgage Payoff Calculator | ✅ No | Nothing | Nothing |
| Pay Raise Calculator | ✅ No | Nothing | Nothing |
| Savings Goal Calculator | ✅ No | Nothing | Nothing |
| VAT & Sales Tax Calculator | ✅ No | Nothing | Nothing |
🔄 Converters
| Tool | Sends what you enter? | Loads from the internet | Saved in your browser |
|---|---|---|---|
| Currency Converter | ✅ No (downloads exchange rates only) | Exchange rates | Nothing |
| Number Base Converter | ✅ No | Nothing | Nothing |
| Temperature Converter | ✅ No | Nothing | Nothing |
| Time Zone Converter | ✅ No | Nothing | Nothing |
| Unit Converter | ✅ No | Nothing | Nothing |
✍️ Text Tools
| Tool | Sends what you enter? | Loads from the internet | Saved in your browser |
|---|---|---|---|
| Case Converter | ✅ No | Nothing | Nothing |
| Diff Checker | ✅ No | Nothing | Nothing |
| Lorem Ipsum Generator | ✅ No | Nothing | Nothing |
| Password Generator | ✅ No | Nothing | Nothing |
| Remove Duplicate Lines | ✅ No | Nothing | Nothing |
| Word Counter | ✅ No | Nothing | Nothing |
👨💻 Developer Tools
| Tool | Sends what you enter? | Loads from the internet | Saved in your browser |
|---|---|---|---|
| Base64 Encode / Decode | ✅ No | Nothing | Nothing |
| Color Converter | ✅ No | Nothing | Nothing |
| Cron Expression Tester | ✅ No | Nothing | Nothing |
| Hash Generator | ✅ No | Nothing | Nothing |
| JSON Formatter & Validator | ✅ No | Nothing | Nothing |
| JSON to CSV Converter | ✅ No | Nothing | Nothing |
| JWT Decoder | ✅ No | Nothing | Nothing |
| Regex Tester | ✅ No | Nothing | Nothing |
| Unix Timestamp Converter | ✅ No | Nothing | Nothing |
| URL Encode / Decode | ✅ No | Nothing | Nothing |
| UUID Generator | ✅ No | Nothing | Nothing |
| YAML to JSON Converter | ✅ No | js-yaml (code) | Nothing |
🖼️ Image Tools
| Tool | Sends what you enter? | Loads from the internet | Saved in your browser |
|---|---|---|---|
| Blur Image | ✅ No | Nothing | Nothing |
| Compress Image to KB | ✅ No | Nothing | Nothing |
| EXIF Remover | ✅ No | Nothing | Nothing |
| HEIC to JPG Converter | ✅ No | heic2any (code) | Nothing |
| Image Compressor | ✅ No | Nothing | Nothing |
| Image Converter | ✅ No | Nothing | Nothing |
| Image Cropper | ✅ No | Nothing | Nothing |
| Image Resizer | ✅ No | Nothing | Nothing |
| Passport Photo Maker | ✅ No | Nothing | Nothing |
| QR Code Generator | ✅ No | qrcode-generator (code) | Nothing |
📄 PDF Tools
| Tool | Sends what you enter? | Loads from the internet | Saved in your browser |
|---|---|---|---|
| Add Page Numbers to PDF | ✅ No | pdf-lib (code) | Nothing |
| Compress PDF | ✅ No | PDF.js, pdf-lib (code) | Nothing |
| Image to PDF | ✅ No | pdf-lib (code) | Nothing |
| Merge PDF | ✅ No | pdf-lib (code) | Nothing |
| PDF Metadata Remover | ✅ No | pdf-lib (code) | Nothing |
| PDF to Image | ✅ No | PDF.js (code) | Nothing |
| PDF to Text | ✅ No | PDF.js (code) | Nothing |
| Reorder PDF Pages | ✅ No | PDF.js, pdf-lib (code) | Nothing |
| Rotate PDF | ✅ No | PDF.js, pdf-lib (code) | Nothing |
| Sign PDF | ✅ No | PDF.js, pdf-lib (code) | Nothing |
| Split PDF | ✅ No | pdf-lib (code) | Nothing |
| Watermark PDF | ✅ No | PDF.js, pdf-lib (code) | Nothing |