Made for frontend developers
Free browser tools for building and testing web apps.
Inspect JWTs, generate edge-case test data, and turn JSON into TypeScript and Zod. Your tool inputs are processed on your device.
Find a developer tool
Start with a development task
All tools →JWT Decoder & Inspector
Decode, inspect, and validate JSON Web Tokens securely in your browser. Includes RFC claim hints and auth chaos simulation.
Open toolMock Data Generator
Generate users, orders, invoices, and difficult strings. Adjust the amount of messy data, build a custom schema, and export JSON or CSV locally.
Open toolJSON to TS & Zod
Convert JSON into TypeScript types and Zod schemas in your browser. Handle nested objects, mixed arrays, and optional fields; copy the generated code.
Open toolPrepare the assets for your interface
Try a font on your own text
Open font studio →Useful workflows, from input to output
Test an API integration
Start with an API response fixture, generate a schema, then use messy mock records to exercise validation and error states.
Prepare an image for the web
Resize to your layout, convert to WebP, and inspect the final file size before downloading.
Share a document
Combine images with the image-to-PDF converter, or merge existing PDFs locally.
Understand how the tools work
Read the implementation guides, inspect the source, and see which features use a network connection.