Guides

The tools do a job. These explain the problem behind it — written to be read once and remembered, not to rank for a keyword.

JSON, YAML and CSV — choosing the right one Three formats for the same data, each good at a different job. The failure modes are more instructive than the feature lists. Thu May 07 2026 00:00:00 GMT+0000 (Coordinated Universal Time) · 8 min Why you should never paste a secret into an online tool The convenience of a web-based decoder is real. So is the fact that you have just handed someone a credential. Thu Apr 02 2026 00:00:00 GMT+0000 (Coordinated Universal Time) · 6 min When a regular expression becomes a denial of service A pattern that works perfectly in testing can hang a server on an input twenty characters long. Here is why, and how to spot one before it ships. Thu May 28 2026 00:00:00 GMT+0000 (Coordinated Universal Time) · 8 min How to verify a downloaded file with SHA-256 Publishers print a checksum next to the download link. Here is what it is actually protecting you from, and how to check it on any operating system. Thu Apr 16 2026 00:00:00 GMT+0000 (Coordinated Universal Time) · 7 min

Why these exist

Every tool on this site solves a narrow problem, and a narrow problem is usually a symptom of a wider one. A JWT decoder is useful; knowing why you should not paste a live token into a random website is more useful. A hash generator computes a checksum; knowing what a matching checksum actually proves — and what it does not — is the part that changes how you work.

These guides are the second half. They are written from experience with the failure modes rather than assembled from other articles, they name the specific traps, and they do not pad.