The web as a general platform

Objectives

By the end of the lesson, you can distinguish the internet from the web, explain why the web touches most areas of computing, and you know the shared example of the course, Kurzuspont.

Why is the web worth studying?

Today an IT professional meets the consequences of web decisions even if they never write HTML. A data analyst gets data from an API, an operations engineer watches the response time of a web service, a security specialist examines a login flow, a mobile developer communicates with server-side endpoints. Basic web knowledge is therefore a common professional language: it is how different fields understand each other.

The course does not teach a framework. Concrete tools change quickly, while the principles behind them (how the client communicates with the server, what an address means, how we protect data, what makes a service fast) stay valid for decades. We build on these.

Internet and web: two different things

In everyday language we use the two words as synonyms, but professionally they are different layers.

The internet is the worldwide system of interconnected computer networks. Its job is to deliver data packets from one machine to another, regardless of what they are used for. Web traffic is part of the internet, but so are email, file transfer, online games, and the background communication of most mobile apps.

The web (World Wide Web, WWW) is a service running on the internet. It is built on three simple ideas:

1. Addressable resources: every document, image, or piece of data has an address (URL, Uniform Resource Locator).
2. A common communication rule: the client and the server talk to each other using HTTP (Hypertext Transfer Protocol).
3. Hypertext: documents can point to each other with links, and a link is an address.

An analogy: the internet is the road network and its vehicles, while the web is one of the services that run on this road network, for example a postal service. The roads remain without the postal service, and other services (such as email) travel on the roads too.

flowchart TB
    subgraph Internet["Internet: an interconnected system of networks"]
        direction LR
        Web["Web: addressable resources, HTTP, hypertext"]
        Mail["Email"]
        Files["File transfer"]
        Games["Online games"]
    end

The diagram shows containment: the web is one service of the internet, it is not identical to it.

The web as a platform

A platform is a common base on which many kinds of solutions can be built without the builders having to produce the base again. The web is like this: anyone can build a service on it, and users do not have to install a separate program. Three properties make it attractive:

• a browser is available on almost every device;
• the standards are open, anyone can implement a browser or a server from them (see lesson 1.5);
• an address is enough for someone to reach the service.

In an IT system, the web can play several roles:

Role	What does it mean?	Example
User interface	People use the functions of the system here	university study system
Communication layer	Programs exchange data through web APIs (Application Programming Interface)	calling a payment provider
Publication surface	Display of documents, news, public data	news portal, regulations
Integration medium	Systems built with different technologies connect through standard interfaces	external login

flowchart LR
    Person[User] -->|uses in a browser| UI[Web interface]
    UI --> Service[Web service]
    Other[Another program] -->|connects through an API| Service
    Service --> Data[Data and functions]

So the same service gives people an interface and programs a connection point.

Who meets web concepts?

Field	Why are web fundamentals important?
Software development	Many applications connect to web APIs, admin interfaces, or online services.
Databases, data analysis	Data often comes from web services and appears in browser interfaces.
Cybersecurity	A large share of the most common attack surfaces are web-based: login, forms, the browser, APIs.
Networks, operations	Web traffic, name resolution, encryption, and availability are daily tasks.
Mobile development	Mobile apps typically talk to the backend through web APIs.
Artificial intelligence	Models and services are often reached through web APIs.
IoT (Internet of Things), embedded systems	Devices often use a web control interface or a cloud service.

The principle is simple: if a system communicates with people or other systems over the internet, we will most likely meet web concepts.

Web decisions have real consequences

The quality of a web service directly affects its users. A badly designed login is a security risk. A slow page causes business loss and annoyance. An interface that ignores accessibility excludes people. Opaque data handling raises legal and ethical questions. The subject therefore gives not only technical knowledge, but also a set of viewpoints for judging responsible digital services.

Worked example: introducing Kurzuspont

The examples of the course all run through one fictional service. Kurzuspont is a university course catalogue and enrolment interface, with the address kurzuspont.example. (According to RFC 2606, the .example ending is a top-level domain reserved for documentation examples, so it does not point to a real site.)

Kurzuspont performs the following tasks:

• students can browse and search the announced courses;
• after logging in they can enrol in a course and cancel the enrolment;
• the instructor sees the list of enrolled students;
• the system is also connected to external services (email, university authentication).

From chapter to chapter we look at the same service through different eyes: how the browser requests the list of courses (chapters 2–3), how the request reaches the server (4), in what form it receives the data (5), how the page is displayed (6), how the student stays logged in (7), how the system can be protected (8), what makes it usable and fast for everyone (9), and what happens when thousands arrive at once as enrolment opens (10).

This is not your project: Kurzuspont shows how the concepts appear in a coherent system.

Common misconceptions

Statement	Clarification
"The internet and the web are the same."	The internet is the network infrastructure; the web is the service built on URLs, HTTP, and hypertext that runs on it.
"Web programming is only for web developers."	Web systems connect many areas of computing.
"The subject is only about HTML and how pages look."	The web is a system of communication, security, data, browsers, and services.
"Technologies change fast, so the subject becomes outdated quickly."	Concrete tools change; protocols and principles are far more lasting.

In brief

• The internet is the system of networks; the web is the service built on addresses, HTTP, and hypertext that runs on it.
• The web is a general platform: it can be an interface, a communication layer, a publication surface, and an integration medium.
• It touches many areas of computing, so web literacy is a common professional language.
• The course guides you through one fictional example, the Kurzuspont university course catalogue.

Review questions

1. Give an example of an internet service that is not part of the web, and justify it!
2. What are the three ideas the web is built on?
3. What roles can the web play in a university study system?
4. Why can basic web knowledge be useful even for someone who never builds a web page?

Learning resources

• How the web works (MDN) — a short overview of clients, servers, DNS, and HTTP.
• A short history of the web (CERN) — the official timeline of the origins of the web.