HTTP / HTTPS

The Hypertext Transfer ProtocolHTTP (Hypertext Transfer Protocol) is the protocol through which browsers and servers exchange web content. HTTPS is the encrypted, secure variant of this protocol.Open glossary entry → (HTTP) governs how browsers or crawlers request web pages from a server and how the server responds. HTTPS (HTTP Secure) is the encrypted variant: data transfer is secured, which matters for privacy and trust and should be the standard today.

With every request, the server returns an HTTP status code describing the outcome:

• 200 – success,
• 301 / 302 – redirectA redirect forwards users and search engines from one URL to another. It can be permanent (301) or temporary (302) and transfers signals to the target URL.Open glossary entry →,
• 404 – not found,
• 403 / 429 – access denied or too many requests.

For search engine optimisationSearch Engine Optimization (SEO) covers all measures that help a website become more visible in unpaid (organic) search results.Open glossary entry →, status codes are revealing because they show what bots actually receive. Server logs reveal whether crawlers such as GooglebotGooglebot is Google's web crawler, which fetches web pages to crawl and index them for Google Search.Open glossary entry → or AI crawlersAI crawlers are automated bots that fetch web pages for AI providers in order to find content, make it available for search functions, retrieve it for answers, or, depending on the provider, use it for model training.Open glossary entry → get successful responses or are blocked, for example by 403 and 429 errors.