Understanding API Versioning: A Simple Guide -Part 1 : Theory
Tags: csharp, beginners, computerscience, api
Published: 2024-06-05 12:31:14

APIs (Application Programming Interfaces) are a crucial part of modern software development. They allow different software systems to communicate with each other, enabling the integration of various services and functionalities. But as software evolves, so do the APIs. This is where API versioning comes into play. In this article, we’ll explore what API versioning is, why it’s important, and how to implement versioning is on [part 2 for this article](https://dev.to/muhammad_taimur/understanding-api-versioning-a-simple-guide-part-1-c-code-1p0e).


## **What is an API?**


Before diving into versioning, let’s quickly understand what an API is. An API is like a waiter in a restaurant. Just as a waiter takes your order and brings back your food from the kitchen, an API takes your request, communicates it to a server, and returns the server’s response to you.

For example, when you use a weather app, the app sends a request to a weather API, which then returns the current weather data.


## **Why Do We Need API Versioning?**


As software and applications grow, APIs need to evolve. New features are added, old ones are modified, and sometimes deprecated. These changes can break existing integrations if not managed properly. This is where API versioning helps.

API versioning allows developers to introduce changes without disrupting the existing API consumers (clients). It helps maintain backward compatibility while rolling out improvements and new features.


## **How Does API Versioning Work?**


API versioning involves assigning different versions to an API. Each version can have different endpoints or functionalities. Here’s a simple example:

Let’s say we have a GET /weather endpoint that returns weather data. Over time, we might want to add new data fields or change the format of the response. Instead of modifying the existing endpoint, we create a new version.

**Example:**

- Version 1 (v1):

`GET /api/v1/weather
Response: { "temperature": 25, "humidity": 60 }`

- Version 2 (v2):

`GET /api/v2/weather
Response: { "temp": 25, "hum": 60, "wind_speed": 10 }`


In this example, v2 introduces a new field (wind_speed) and changes the field names (temperature to temp, humidity to hum). Clients using v1 are unaffected by these changes.

## **Common API Versioning Strategies**

Below are the 3 most common ways of API Versioning used by developers

**1. URL Path Versioning**

This method includes the version number in the URL path.

`GET /api/v1/resource
GET /api/v2/resource`

**2. Query Parameter Versioning**

This method includes the version number as a query parameter.

`GET /api/resource?version=1
GET /api/resource?version=2`

**3. Header Versioning**

This method specifies the version number in the request header.

`GET /api/resource
Headers: { "API-Version": "1" }`

To visualize this concept, here’s a simple wording:

Client 1 requests data using v1 endpoint.
Server responds with data in v1 format.
Client 2 requests data using v2 endpoint.
Server responds with data in v2 format.

This separation ensures that changes in v2 do not affect clients using v1. Hence both Apis works as expected.

## **Conclusion**

API versioning is essential for maintaining the stability and reliability of APIs as they evolve. It allows developers to introduce new features and improvements without breaking existing clients. By understanding and implementing API versioning, you can ensure a smooth transition and continued compatibility for your API consumers.

Whether you choose URL path, query parameter, or header versioning, the goal remains the same: to manage changes effectively and keep your API robust and user-friendly.

Happy coding!

Feel free to ask questions or share your thoughts in the comments below! If you found this article helpful, don’t forget to like and share it.