About sde.tools

What this site is

sde.tools is a free collection of 84 small utilities for software developers, DevOps engineers and system administrators: encoders and decoders, format converters, hash and key generators, network calculators, and reference sheets. They are grouped into 9 categories and each one has its own page, so you can bookmark the tool you use rather than the site.

There is no account, no sign-up and no paid tier. Every tool is usable the moment its page loads.

How the tools work

The tools are JavaScript that runs in your browser. When you paste a token into the JWT decoder or a password into the bcrypt generator, the computation happens on your device and the input is not sent to our servers. That matters for the things developers routinely paste into tools like these: access tokens, private keys, configuration files and customer data.

The site itself does use analytics to count page views, and a small number of tools fetch public resources they need. The privacy page lists exactly what is and is not collected.

How the site is built

sde.tools is built with Next.js and React and served as static pages.

• Every tool is a statically generated page with its own URL, so it loads quickly and can be linked to directly.
• The most used tools have a written guide below them explaining the underlying format or algorithm, with worked examples and the tool's known limits.
• The tools' logic is covered by an automated test suite.

Accuracy and limits

These are convenience tools. They are tested, but they are not a substitute for the reference implementation of a standard or for a security review. Where a tool deliberately does less than you might expect, its guide says so: for example, the JWT decoder shows a token's contents but does not verify its signature.

If you find a wrong result or a bug, please report it.