How to compare two versions of a text, config file or code, and read the diff
“What changed?” is hard to answer by eye. Here’s how a diff works, when to compare line by line or word by word, and how to read the results in the…
Jimel S.·4 min read
HTTP status codes explained for site owners: 2xx, 3xx, 4xx and 5xx
Every response starts with a three-digit code that browsers mostly hide but search engines and uptime monitors read first. Here’s what each family…
Jimel S.·4 min read
XML sitemaps search engines can read: limits and common errors
One unescaped character can stop a crawler reading the rest of your sitemap. Here’s what belongs in an XML sitemap, the limits set by sitemaps.org…
Jimel S.·4 min read
Heading structure: one H1, no skipped levels, and why it matters
Headings are how readers skim a page and how assistive technology moves around it. Here’s what the HTML standard and WCAG ask for, what Google…
Jimel S.·4 min read
How to write titles and meta descriptions that fit Google’s search results
Google cuts titles and snippets to fit the screen, and sometimes writes its own. Here’s what Google’s documentation actually says, and how to…
Jimel S.·4 min read
UUIDs explained: v4 vs v7, and when to use them as database IDs
A UUID is a 128-bit ID anyone can create without asking a central server. Here’s how to read one, the difference between random version 4 and…
Jimel S.·4 min read
Base64 vs URL encoding: what each is for, and the mistakes that break things
Base64 and URL encoding both turn data into “safe” characters, but they solve different problems, and neither hides anything. Here’s when to use…
Jimel S.·4 min read
Unix timestamps explained: seconds vs milliseconds, time zones and 2038
A log says 1794398400, a database says 1794398400000, and a scheduled job runs an hour early. Here’s what a Unix timestamp really is, how to tell…
Jimel S.·4 min read
Email not arriving? Check where a domain’s mail goes with MX records
When messages bounce or vanish, start with two DNS checks: the MX records that say where a domain’s mail is delivered, and the reverse DNS of the…
Jimel S.·4 min read
What is my IP address? Public vs private, IPv4 vs IPv6, and what sites can see
Your settings say 192.168.1.23, but the support desk wants a different number. Here’s the difference between private and public addresses, how IPv4…
Jimel S.·4 min read
Is your website down? A layer-by-layer troubleshooting guide for site owners
When your site stops loading, work through it in the same order a browser does: DNS, connection, certificate, HTTP response and content. This guide…
Jimel S.·4 min read
Leaked an API key? How to rotate secrets without breaking production
Your hosting platform was breached, a .env file reached GitHub or a laptop went missing. Here’s the order to rotate secrets in, how to swap keys…
Jimel S.·4 min read