Choose the tool you need
Developer tools
- JSON to ERDPaste your database schema JSON and get an interactive ERD.
- API TesterSend an HTTPS request from your browser and read the JSON response.
- JSON Field ExtractorPaste a JSON array and a field path to get a flat array of the matching values.
- JWT InspectorDecode a JWT, read its claims in local time, and verify an HMAC signature offline.
General tools
- QR Code & Barcode GeneratorTurn any text into a coloured QR code or barcode, then export PNG, JPG or SVG.
- SVG Recolor & OptimizerUpload an SVG, recolour it with a visual palette, and strip out unused code.
- Photo Metadata Viewer & ScrubberSee the GPS coordinates and serial numbers hidden in a photo, then strip them without touching a pixel.
- Genogram & Ecomap MakerMap a family across three generations, then map the systems around it. Export PNG, JPG or SVG.
- Text Format CleanerStrip messy HTML styling, fullwidth characters and hidden characters from pasted text.
- Excel Column TransferMatch rows by key and copy columns from one Excel into an existing form, formatting intact.
Finance tools
- Compound Interest CalculatorSee how principal, rate and contributions compound into a year-by-year schedule.
- Freelance Rate CalculatorEnter your target income, insurance and fixed costs to find your minimum viable hourly rate.
- Cash Conversion Cycle CalculatorTurn receivables, inventory and payables into DSO, DIO, DPO and the days you fund yourself.
- Household Cash Cycle CalculatorWork out how many days of ordinary spending you have to bridge yourself, and how much cash that needs.
- Unit Price ComparatorEnter the price and size of a few products and see which one is actually cheaper per unit.
How it works
Every tool runs entirely in your browser — nothing you paste is sent to a server. Check the network tab in devtools if you want to confirm that yourself. No analytics are installed here, and no user profile gets built.
There are no accounts, so nothing syncs across devices. Because there’s no backend, API Tester can only reach services that allow cross-origin requests — that’s a browser limitation, not a missing feature, and no proxy will be added to work around it. Some tools keep your last input in local browser storage so you can pick up where you left off; clearing it removes the data.
Missing a tool, or found a bug? Contact us.