Web Development · Intermediate level

Intermediate level · Module 4: Back-End Basics with Node.js and Express · Lesson 1 of 3

Clients, Servers and REST

Understand how front ends talk to back ends and design endpoints that follow REST conventions.

In this lesson you will

  • Explain the client–server model
  • Design RESTful endpoints with suitable methods and status codes

Key concepts

client and serverresource and endpointHTTP methodsstatus codes

The lesson

The front end runs in the user's browser; the back end runs on a server, holds the data and enforces the rules. They communicate over HTTP, usually exchanging JSON.

REST organises an API around resources: GET /api/courses lists courses, GET /api/courses/7 returns one, POST /api/enquiries creates an enquiry. Methods describe the action and paths name the resource.

Status codes tell clients what happened: 200 OK, 201 Created, 400 Bad Request for invalid input, 404 Not Found and 500 for unexpected server errors.

Step by step

  1. List the resources the training centre needs.
  2. Design endpoints with methods and paths.
  3. Choose status codes for success and failure cases.
  4. Write example JSON for each response.

Practice activity

Write the API design for the training centre system.

Expected result: A design with endpoints, methods, status codes and example JSON for each.

Check your understanding

  1. Which method and path would create an enquiry?

    Show answer

    POST /api/enquiries.

  2. What does status 201 mean?

    Show answer

    A resource was created.

Taught live by an instructor — online or in person. Free course lessons are for self-study and do not lead to a certificate — see registration options.