articles / Tools
Developer tools
These are the small conversions and lookups that come up constantly during development: validating a blob of JSON, decoding a Base64 string, encoding a value for a URL, generating an identifier, or making sense of a Unix timestamp. Each one is a single-purpose tool that does its job and gets out of the way.
Everything here runs as JavaScript in your own browser. The text you paste is never sent to a server, logged, or stored anywhere, which makes these safe to use on values you would not want to paste into a random website. They also keep working with the tab offline once the page has loaded.
JSON formatter & validator
Pretty-print and validate JSON. Errors are reported with a position.
Base64 encode / decode
Unicode-safe Base64 using the browser's text encoder.
URL encode / decode
Percent-encode a component for safe use in a query string, or decode one.
UUID generator
Version 4 UUIDs from the browser's cryptographic random source.
Unix timestamp converter
Convert a Unix timestamp (seconds or milliseconds) to a readable date, both local and UTC.
Private by design
There are plenty of online formatters and decoders, but most of them send whatever you paste to a server. For anything that might contain a token, a customer record, or an internal payload, that is a quiet risk. These tools avoid it entirely by doing the work locally: the UUID generator uses the browser's cryptographic random source, the Base64 and text tools use the standard encoder built into the platform, and nothing leaves the page.
They are intentionally minimal rather than feature-packed. If you need something more advanced, the cheatsheets cover the underlying APIs, and the articles explain the concepts behind them in depth.