What happens when you press Enter

Type a URL and hit Enter. In the next few hundred milliseconds, a precise sequence plays out — and knowing it turns the web from magic into machinery.

• 1. DNS — the browser asks: what IP address is example.com? (a global phone book, cached everywhere)
• 2. TCP/TLS — the browser opens a connection to that server and secures it (the padlock: HTTPS).
• 3. HTTP request — the browser asks for the page: 'GET /' plus headers describing itself.
• 4. HTTP response — the server replies with a status code and the HTML document.
• 5. Parse — the browser reads HTML top to bottom, building the page's map (the DOM).
• 6. Fetch subresources — CSS, JavaScript and images discovered in the HTML are each fetched the same way.
• 7. Render — styles are applied, layout is computed, JavaScript runs, pixels appear.

Status codes, the useful five

• 200 OK — here's the content you asked for.
• 301 / 308 — moved permanently; browsers and search engines update their links.
• 404 Not Found — the path exists in the URL scheme but no page lives there.
• 500 Internal Server Error — the server itself failed while producing the page.
• 429 Too Many Requests — you (or everyone) hit a rate limit; slow down.