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ANVISoftware Solutions

Web API Development

Intermediate18-24 hours5 modules18 lessons

Design and build APIs other developers can use without asking you questions: clear contracts, honest errors, pagination, versioning and documentation.

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Prerequisites

  • ASP.NET Core basics: routing, controllers, dependency injection

Technologies

About this course

Building an endpoint that returns data is straightforward. Building an API that a mobile team can consume for two years without confusion is a different skill, and that is what this course is about.

You will design contracts before implementations, separate the shapes you expose from the shapes you store, and settle on one error format that every endpoint honours. These decisions look like overhead on day one and save considerable time by month three.

The course covers the operational side too: paginating large collections, versioning without breaking existing callers, documenting with OpenAPI, and securing endpoints so authorisation is enforced rather than assumed.

Course roadmap

All 18 lessons are written and available.

Module 01

API Foundations

What an API is, and the HTTP vocabulary you need to design one that behaves predictably.

4/4 ready
  1. 01What Is an API?Explain what an API is, who consumes it, and why the contract matters more than the implementation.12 min
  2. 02HTTP MethodsChoose between GET, POST, PUT, PATCH and DELETE, and respect safety and idempotency.15 min
  3. 03Status CodesReturn the code that accurately describes what happened.16 min
  4. 04JSON and SerialisationControl how objects are converted to and from JSON.16 min

Module 02

Designing the Contract

Decide what you expose before you decide how to build it.

5/5 ready
  1. 01REST Principles, Applied PragmaticallyApply REST where it helps and depart from it deliberately where it does not.17 min
  2. 02Designing Resources and URLsModel endpoints around resources with predictable, stable addresses.16 min
  3. 03DTOs and Why Not to Expose EntitiesSeparate the shapes you expose from the shapes you store.18 min
  4. 04Request ValidationReject invalid requests at the boundary with clear, specific messages.17 min
  5. 05A Consistent Error FormatDefine one error response shape every endpoint honours.16 min

Module 03

Working with Collections

Endpoints that return lists need paging, filtering and sorting before the data grows.

3/3 ready
  1. 01PaginationPage large collections, and compare offset and cursor approaches.18 min
  2. 02Filtering and SortingLet callers narrow and order results without enabling abuse.17 min
  3. 03SearchingOffer text search that performs acceptably as data grows.17 min

Module 04

Documentation and Change

Make the API understandable, then change it without breaking the people using it.

2/2 ready
  1. 01OpenAPI DocumentationProduce accurate machine-readable documentation from your code.16 min
  2. 02VersioningIntroduce breaking changes without breaking existing consumers.18 min

Module 05

Security and Testing

Protect the endpoints, then prove the protection works.

4/4 ready
  1. 01Authenticating API CallersVerify caller identity with tokens, and validate them correctly.18 min
  2. 02Authorizing RequestsEnforce what each caller may do, including ownership checks on records.19 min
  3. 03Testing an APITest endpoints end to end, including authorisation and failure paths.18 min
  4. 04API PerformanceMeasure latency and remove the common causes of slow endpoints.19 min

Projects for this course

Intermediate

Employee Management API

A production-shaped web API: validated, paged, documented, secured, backed by a real database and covered by tests.

25-35 hours
Intermediate

Blog API

A smaller API focused on relationships, slugs, publishing state and search.

15-20 hours

On completion

What you should take away

  • An API is a contract, and contracts are easier to honour when written down first
  • DTOs protect you from having your database schema become your public interface
  • Consistent errors and pagination are what make an API pleasant to consume
  • Versioning is a planning decision made before the first breaking change, not after

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