Acronyms you will see around the site
Every three-letter mystery, decoded. Type to filter.
The plain-text language browsers and servers use to request and serve pages.
HTTP over an encrypted (TLS) connection. The S stands for Secure.
The cryptography behind HTTPS. SSL is the older name; the protocol used today is really TLS.
The phone book that turns domains into IP addresses.
The transport layer underneath HTTP.
Server processing time, end to end.
The header that locks browsers to HTTPS.
A header that limits what your page is allowed to load.
Rules about which other domains may read your responses from JavaScript.
Meta tags that control how your link looks when shared on social platforms.
What Google or Bing returns for a query.
Filters incoming traffic and can block scrapers, bots, or attacks.
2xx is success, 3xx is redirect, 4xx is a client error (like 404), 5xx is a server error.
A POST request your monitoring sends to a URL you own when something happens, so your own code can react to events like downtime.
A signature computed from a shared secret. Webhook payloads carry one so receivers can prove the sender is genuine.
The period from a confirmed failure to recovery. Status pages list incidents; uptime percentages are calculated from them.
If an alert isn't acknowledged within a set time, a second contact is notified automatically so outages never sit unseen.
A shareable page showing live state, 30-day uptime, and incident history for chosen sites.
The list inside an SSL certificate of every hostname it covers. www and non-www must both be listed (or use a wildcard).
Definitions only get you so far; the acronyms come alive in the guides. SSL, TLS, HSTS, CSP, HMAC and SAN get the full story in the security guide, while DNS, TCP and TTFB are timed stage by stage in the performance guide.
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