Why versioning prevents breaking changes in Rest API - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to specify the API version in the URL path.

Rest API

GET /api/[1]/users

Drag options to blanks, or click blank then click option'

Av1

Bversion

Capi

Dusers

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'version' or 'api' instead of the version number.

API versioning is often done by including the version number in the URL path, like /api/v1/.

2fill in blank

medium

Complete the code to add a new field in version 2 of the API without breaking version 1.

Rest API

{
  "name": "Alice",
  "email": "[e-mail]",
  "[1]": "123-456-7890"
}

Drag options to blanks, or click blank then click option'

Aphone

Bversion

Cage

Daddress

Attempts:

3 left

💡 Hint

Common Mistakes

Changing existing fields or removing fields in version 1.

Adding a new field like phone in version 2 keeps version 1 unchanged, preventing breaking changes.

3fill in blank

hard

Fix the error in the versioning header to specify the API version correctly.

Rest API

Accept: application/json; version=[1]

Drag options to blanks, or click blank then click option'

Aversion2

Bv2

C1.0

D2

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'v2' or 'version2' which may not be recognized.

The version in the Accept header is usually a simple number like 2 without extra letters.

4fill in blank

hard

Fill both blanks to create a new API version path and keep the old one working.

Rest API

GET /api/[1]/products  # old version
GET /api/[2]/products  # new version

Drag options to blanks, or click blank then click option'

Av1

Bv2

Cversion1

Dversion2

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'version1' or 'version2' which is less common.

Using v1 and v2 in the URL path allows both versions to work side by side.

5fill in blank

hard

Fill all three blanks to show how versioning prevents breaking changes by supporting multiple versions.

Rest API

responses = {
  "[1]": {"status": 200, "data": {...}},
  "[2]": {"status": 200, "data": {..., "[3]": "new field"}}
}

Drag options to blanks, or click blank then click option'

Av1

Bv2

Cextra_info

Ddeprecated

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'deprecated' as a field name or mixing version keys.

This shows version 1 response without the new field, and version 2 response with the added extra_info field, preventing breaking changes.

Practice

1. Why is versioning important in REST APIs?

easy

A. It makes the API run faster.

B. It reduces the number of API endpoints.

C. It allows clients to use old API features without breaking when new changes happen.

D. It automatically fixes bugs in the API.

Solution

1. Step 1: Understand the role of versioning

   Versioning separates different stages of an API so changes don't break existing clients.

2. Step 2: Identify the benefit for clients

   Clients can keep using the old API version safely while new versions add features or fix bugs.

3. Final Answer:

   It allows clients to use old API features without breaking when new changes happen. -> Option C

4. Quick Check:

   Versioning prevents breaking changes = B [OK]

Hint: Versioning keeps old and new APIs separate to avoid breakage [OK]

Common Mistakes:

• Thinking versioning speeds up the API
• Believing versioning reduces endpoints
• Assuming versioning fixes bugs automatically

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

easy

A. /api/users/v1

B. /api/v1/users

C. /v1api/users

D. /api/users?version=1

Solution

1. Step 1: Identify common versioning URL patterns

   Versioning is usually done by adding a version segment like /v1/ after the base API path.

2. Step 2: Check each option

   /api/v1/users uses /api/v1/users which is the standard and clear way to version APIs.

3. Final Answer:

   /api/v1/users -> Option B

4. Quick Check:

   Version in URL path = A [OK]

Hint: Version usually appears as /v1/ in the API path [OK]

Common Mistakes:

• Putting version after resource name
• Combining version and resource without slash
• Using query parameters for versioning (less common)

3. Given this API change: adding a new required field to the user creation endpoint without versioning, what is the likely result for existing clients?

medium

A. The API will automatically update clients to send the new field.

B. Existing clients will continue working without any issues.

C. The API will ignore the missing field and use a default silently.

D. Existing clients will break because they don't send the new required field.

Solution

1. Step 1: Understand impact of adding required fields without versioning

   Adding a required field means clients must send it or the API rejects the request.

2. Step 2: Predict behavior for old clients

   Old clients don't send the new field, so their requests fail, causing breakage.

3. Final Answer:

   Existing clients will break because they don't send the new required field. -> Option D

4. Quick Check:

   Adding required field breaks old clients = D [OK]

Hint: New required fields break old clients without versioning [OK]

Common Mistakes:

• Assuming API auto-fills missing required fields
• Thinking old clients keep working unchanged
• Believing API updates clients automatically

4. You have an API with versioning: /api/v1/users and /api/v2/users. You accidentally remove a field in v2 that clients still use in v1. What is the best fix?

medium

A. Keep the field in v1 and remove only in v2 to avoid breaking v1 clients.

B. Remove the field from both versions immediately.

C. Remove the field from v1 and v2 but notify clients to update.

D. Merge v1 and v2 into a single version without the field.

Solution

1. Step 1: Understand versioning purpose

   Versioning allows old clients to keep using old API features safely.

2. Step 2: Apply versioning to field removal

   Removing a field only in v2 keeps v1 stable for clients still using it.

3. Final Answer:

   Keep the field in v1 and remove only in v2 to avoid breaking v1 clients. -> Option A

4. Quick Check:

   Remove features only in new versions = A [OK]

Hint: Remove features only in new versions, keep old stable [OK]

Common Mistakes:

• Removing fields from all versions at once
• Merging versions and breaking old clients
• Ignoring impact on old clients

5. You want to add a new optional feature to your API without breaking existing clients. Which versioning strategy best supports this?

hard

A. Create a new version (e.g., /api/v2) with the feature, keep /api/v1 unchanged.

B. Add the feature directly to /api/v1 and remove old features.

C. Change the API URL to /api/users without version and add the feature.

D. Force all clients to update to the new feature immediately.

Solution

1. Step 1: Identify safe way to add features

   Adding a new version keeps old clients working and adds new features safely.

2. Step 2: Evaluate options

   Create a new version (e.g., /api/v2) with the feature, keep /api/v1 unchanged. creates /api/v2 with new feature and keeps /api/v1 stable, preventing breakage.

3. Final Answer:

   Create a new version (e.g., /api/v2) with the feature, keep /api/v1 unchanged. -> Option A

4. Quick Check:

   New version for new features = C [OK]

Hint: Add features in new versions, keep old stable [OK]

Common Mistakes:

• Changing old versions directly
• Removing old features immediately
• Not using versioning at all