DataStays is a local-first toolkit for developers who handle sensitive data: format, validate, decode, convert and inspect payloads entirely in your browser, so what you paste never leaves your device.
Most online formatters and decoders upload whatever you paste to a server. For an API token, an internal payload, or a customer record, that is a quiet data-exfiltration risk. DataStays does the work in your browser instead, and makes that claim verifiable (see Privacy) and enforces it in the build.
When you format, minify, or validate JSON, the important JSON source details are preserved exactly: large integers, number forms, key order and duplicate keys all survive because those tools work on your source text rather than a parsed-and-restringified copy. Some tools that transform structure, like Flatten or Diff, work on parsed values. The JWT tool decodes and verifies locally and never transmits your token.
After your first visit, DataStays works with the network fully disabled — itself proof that the tools run on your device.