Versioning best practices in Rest API - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is API versioning?

API versioning is the practice of managing changes in an API by assigning version numbers. It helps clients know which version they are using and ensures backward compatibility.

beginner

Name two common ways to include version information in a REST API.

1. In the URL path (e.g., /v1/users)
2. In the HTTP header (e.g., Accept: application/vnd.example.v1+json)

intermediate

Why is semantic versioning important in API versioning?

Semantic versioning uses a format like MAJOR.MINOR.PATCH to communicate the type of changes: major for breaking changes, minor for new features without breaking, and patch for fixes. This helps clients understand impact before upgrading.

intermediate

What is a backward-compatible change in API versioning?

A backward-compatible change means the new API version does not break existing clients. Examples include adding new optional fields or endpoints without removing or changing existing ones.

beginner

Why should you avoid breaking changes in minor or patch versions?

Breaking changes can cause existing clients to fail. Minor and patch versions should only add features or fix bugs without breaking compatibility to keep clients working smoothly.

Which of the following is a common way to specify API version?

A In the URL path like /v1/resource

B In the database schema

C In the client’s local storage

D In the server’s file system

API versions are often included in the URL path to clearly indicate which version the client is using.

What does a major version change usually indicate?

A No changes at all

B New features without breaking changes

C Bug fixes only

D Breaking changes that may require client updates

Major version changes signal breaking changes that might require clients to update their code.

Which header is commonly used to specify API version?

A Content-Type

B User-Agent

C Accept

D Authorization

The Accept header can specify the desired API version using media type versioning.

What should you do if you want to add a new optional field to an API response?

A Increase the major version

B Increase the minor version

C Remove an existing field

D Do not change the version

Adding new optional fields is a backward-compatible feature and fits a minor version increase.

Why is it important to keep old API versions available for some time?

A To allow clients to upgrade at their own pace

B To confuse clients

C To increase server load

D To avoid writing documentation

Maintaining old versions lets clients upgrade when ready, avoiding sudden breaks.

Explain the main strategies for versioning a REST API and when to use each.

Think about how clients specify which API version they want.

Describe semantic versioning and why it matters for API versioning.

Consider how version numbers communicate change types.

Practice

1. What is the main reason to use versioning in a REST API?

easy

A. To hide the API from users

B. To make the API faster

C. To reduce the number of API endpoints

D. To keep the API stable and avoid breaking existing clients

Solution

1. Step 1: Understand API stability

   Versioning helps keep the API stable by allowing changes without breaking existing users.

2. Step 2: Identify the main goal of versioning

   The main goal is to avoid breaking existing clients when the API changes.

3. Final Answer:

   To keep the API stable and avoid breaking existing clients -> Option D

4. Quick Check:

   Versioning = Stability [OK]

Hint: Versioning protects old users from breaking changes [OK]

Common Mistakes:

• Thinking versioning makes API faster
• Believing versioning reduces endpoints
• Assuming versioning hides the API

2. Which of the following is a correct way to include versioning in a REST API URL?

easy

A. /api/v1/users

B. /api/users/v1

C. /v1/api/users

D. /users/api/v1

Solution

1. Step 1: Identify common versioning URL pattern

   The standard practice is to put the version right after the base API path, like /api/v1/.

2. Step 2: Check each option

   Only /api/v1/users follows the common pattern where version is after /api/.

3. Final Answer:

   /api/v1/users -> Option A

4. Quick Check:

   Version in URL path = /api/v1/ [OK]

Hint: Version usually goes right after /api/ in URL [OK]

Common Mistakes:

• Placing version after resource name
• Putting version before /api/
• Adding version at the end of URL

3. Given this API request header: Accept: application/vnd.example.v2+json, what version of the API is being requested?

medium

A. Version 3

B. Version 1

C. Version 2

D. No version specified

Solution

1. Step 1: Analyze the Accept header format

   The header uses media type versioning with 'v2' indicating version 2.

2. Step 2: Identify the version number

   The 'v2' in 'application/vnd.example.v2+json' means version 2 is requested.

3. Final Answer:

   Version 2 -> Option C

4. Quick Check:

   Header v2 means API version 2 [OK]

Hint: Look for 'v' followed by number in Accept header [OK]

Common Mistakes:

• Ignoring 'v2' and assuming version 1
• Confusing media type with version
• Assuming no version if not in URL

4. You have an API that uses URL versioning like /api/v1/resource. You want to upgrade to version 2 but keep version 1 working. What is the best fix if your current code overwrites the version path and breaks v1?

medium

A. Create separate routes for /api/v1/resource and /api/v2/resource

B. Remove version from URL and use query parameters instead

C. Only keep /api/v2/resource and delete /api/v1/resource

D. Use the same code for both versions without changes

Solution

1. Step 1: Understand versioning goal

   Versioning allows multiple versions to coexist so old clients keep working.

2. Step 2: Fix route handling

   Separate routes for each version keep both versions working without conflict.

3. Final Answer:

   Create separate routes for /api/v1/resource and /api/v2/resource -> Option A

4. Quick Check:

   Separate routes = keep versions working [OK]

Hint: Keep old and new versions on separate routes [OK]

Common Mistakes:

• Overwriting old version routes
• Removing version info completely
• Using same code for different versions

5. You want to design an API versioning strategy that allows clients to specify the version either in the URL path or in a custom header. Which approach best follows versioning best practices?

hard

A. Ignore versioning and always use the latest API version

B. Support both methods but clearly document and prefer one as primary

C. Allow clients to mix URL and header versions freely without restrictions

D. Use query parameters for versioning only

Solution

1. Step 1: Understand consistency in versioning

   Best practice is to be consistent and clear about versioning methods.

2. Step 2: Choose a primary versioning method

   Supporting both but preferring one and documenting it helps developers avoid confusion.

3. Final Answer:

   Support both methods but clearly document and prefer one as primary -> Option B

4. Quick Check:

   Clear, consistent versioning = best practice [OK]

Hint: Pick one versioning method as main, document it well [OK]

Common Mistakes:

• Mixing versions without clear rules
• Ignoring versioning and breaking clients
• Using only query parameters without reason