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Web server: what it is, how it works, and Apache vs Nginx vs IIS
A web server takes a browser request and returns a page, file, or error. It’s both software (Apache, Nginx, IIS) and the machine or cloud where it runs.
Follow the chain from domain to DNS to HTTPS response, then pick Apache, Nginx, or IIS for the job — not nostalgia for outdated local packages.
In plain words
Library analogy: the reader (browser) asks for a book (URL); the librarian (web server) finds the material in storage and hands it over. Unlike one book checked out, a site can be “read” by thousands at once.
A sysadmin will say “hardware and network”; a developer — “software that serves HTTP”. Both are right.
Jobs and functions
The server accepts requests, may run a backend (PHP, Node, Python…), returns HTML/files, writes logs, can restrict access, and serve related roles (static delivery, proxy).
Typical loop:
- accept the request;
- find the resource or build a response via the app;
- return status and response body;
- log the hit;
- with HTTPS — keep an encrypted channel.
How a request flows
The user types an address or clicks a link. DNS turns the name into an IP. The browser sends an HTTPS request. The server handles it and returns a page or an error code (404, 500…).
For a site to open you need:
- hosting or a server with enough resources;
- web server software;
- a domain and DNS record;
- site files / an application;
- an HTTPS certificate (usually via Let’s Encrypt or the hosting panel).
Apache, Nginx, IIS
Apache — shared-hosting classic, modularity, familiar .htaccess. Nginx — strong on static and as a reverse proxy. IIS — Windows Server ecosystem.
In practice:
- small site on hosting — often Apache or Nginx “out of the box” from the panel;
- high load / microservices — Nginx (or analogue) in front of the app;
- corporate Windows stack — IIS.
Rough cheat sheet
| Software | Strengths | Where you often see it |
|---|---|---|
| Apache | Flexibility, .htaccess | Shared hosting, CMS |
| Nginx | Static, proxy, load | Prod, CDN setups |
| IIS | Windows integration | Corporate .NET environments |
Local stacks for development
OpenServer, XAMPP and similar packs suit beginners. Denver is long outdated — don’t aim at it in the 2020s. Teams more often use Docker or built-in framework environments.
Local is for breaking and fixing the site safely — not to replace production hosting.
Minimum to start:
- PHP/Node + DB per project needs;
- HTTPS in prod (locally — as needed);
- matching major versions with prod when possible.
Link to SEO and site availability
If the server returns 5xx, blocks bots, or slows TTFB, both people and indexing suffer. After a host change check response codes, redirects, and HTTPS.
After a move:
- home and key URLs return 200;
- www/non-www and http→https are consistent;
- sitemap and robots are reachable;
- no mass 404s on old paths.
FAQ
Is a web server a computer or a program?
Both meanings are alive: software that answers HTTP(S) requests, and the server environment (VPS/dedicated/cloud) where that software runs.
How does Apache differ from Nginx?
Both serve sites. Nginx is often a fast front (static, proxy); Apache is flexible and familiar on many shared hosts. In practice they’re often combined.
Why HTTPS?
It encrypts traffic between browser and server. Today it’s a baseline standard, plus a requirement of many browsers and search engines.
Does a small site need its own server?
Usually no: hosting/VPS from a provider is enough. Your own hardware makes sense for special loads and admin competence.
What is a local server for development?
An environment on your PC (Docker, OpenServer, XAMPP and analogues) to run the site without deploying to production.
Does the web server alone get you into TOP?
No. A healthy server keeps the site reachable and fast enough for people and crawlers. Rankings still need content and promotion — TOP planned for 2–6 months after start.
Need a hosting and uptime audit?
We’ll check server responses, HTTPS, and bottlenecks — so tech doesn’t eat SEO and ads.
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