Versioning best practices in Rest API - Time & Space Complexity

Time Complexity: Versioning best practices

O(n)

Understanding Time Complexity

When we add versioning to a REST API, it changes how the system handles requests over time.

We want to know how the time to process requests grows as versions increase.

Scenario Under Consideration

Analyze the time complexity of handling API requests with versioning.

// Example: Simple version check in API request handler
function handleRequest(request) {
  switch(request.version) {
    case 'v1':
      return handleV1(request);
    case 'v2':
      return handleV2(request);
    default:
      return handleDefault(request);
  }
}
    

This code chooses the right version handler based on the request's version.

Identify Repeating Operations

Look for repeated checks or loops when processing versions.

• Primary operation: Checking the request version against known versions.
• How many times: Once per request, but the number of versions checked can grow.

How Execution Grows With Input

As the number of API versions increases, the time to find the right handler grows.

Number of Versions (n)	Approx. Checks
3	3 checks
10	10 checks
100	100 checks

Pattern observation: More versions mean more checks, so time grows linearly.

Final Time Complexity

Time Complexity: O(n)

This means the time to handle a request grows in direct proportion to the number of API versions.

Common Mistake

[X] Wrong: "Adding more versions won't affect request handling time because it's just a simple check."

[OK] Correct: Each new version adds another check, so handling time increases with more versions.

Interview Connect

Understanding how versioning affects request handling time helps you design APIs that stay fast as they grow.

Self-Check

"What if we used a dictionary or map to store version handlers instead of a switch? How would the time complexity change?"