Developer Tools
Format, encode, generate โ the everyday coding utilities.
About developer tools
Developer tools are the small utilities you reach for a dozen times a day and never think about until one is missing โ pretty-printing a minified API response, decoding a JWT to see why an auth check is failing, generating a batch of UUIDs for test fixtures, or checking whether a colour pair actually passes contrast requirements.
Every tool in this category runs entirely in your browser. That is a deliberate choice rather than a technical shortcut: the things developers paste into online formatters are frequently production API responses, staging tokens and config files containing real credentials. Pasting those into a server-side tool means handing them to someone else's log files. Here the parsing happens locally, so nothing is transmitted.
If you are picking between similar tools: use the JSON Formatter when you need to validate as well as indent, since it reports the position of a syntax error rather than just failing. Use the JWT Decoder for inspecting claims and expiry, but remember it decodes rather than verifies โ a decoded token tells you what it claims, not whether the signature is valid. Reach for the Hash Generator when comparing checksums, and the Color Contrast Checker before shipping any interface change that touches text colour.
Frequently asked questions
Is it safe to paste production data into an online formatter?
Not usually โ most online formatters post your input to a server, where it may be logged. The tools in this category are the exception: they run in your browser, so the data never leaves your machine. You can verify this by opening your browser's network tab and watching for outbound requests while you use one, or by disconnecting from the network and confirming the tool still works.
Does the JWT Decoder verify the token signature?
No, and no browser-based tool honestly can. Verifying a signature requires the signing secret or public key, which you should never paste into a web page. The decoder shows you the header, payload and expiry so you can debug what a token claims. Signature verification belongs in your backend.
Which formatter should I use for a config file?
Match the tool to the syntax: the YAML Formatter for Kubernetes manifests, CI pipelines and Docker Compose files; the XML Formatter for build files and legacy config; the JSON Formatter for package manifests and API payloads. Using a JSON formatter on YAML will simply fail, since indentation-significant syntax cannot be reformatted by a brace-aware parser.
Are generated UUIDs and passwords genuinely random?
They use the browser's Web Crypto API, which is a cryptographically secure random source โ the same one used for real key generation, not Math.random(). That makes them suitable for production identifiers and passwords.