Versioning Naming

About

Version naming defines how API versions are represented in endpoints, documentation, and contracts. It ensures:

Predictability → Clients instantly know which version they’re using.
Clarity → Developers can differentiate between versions without confusion.
Stability → Older versions remain accessible while newer versions evolve.

Without clear naming, breaking changes become hard to track and clients may unknowingly use deprecated versions.

Core Principles

1. Be Explicit About Versions

Never rely on “hidden” versioning logic - make version identifiers visible in URLs, headers, or media types.

Bad:

/users

(Version unknown - may change without warning)

Good:

/v1/users

(Clear which version is being used)

2. Use a Consistent Version Format

Major-only for large breaking changes: v1, v2
Semantic versioning (optional for APIs): v1.2.3
No leading zeros → Avoid confusion (v01 is bad)
Always lowercase ‘v’ + number for URLs

Bad:

/Version1/users
/v01/users

Good:

/v1/users
/v2.1/users

3. Match Version Naming to Versioning Strategy

URI versioning → /v1/resource
Query parameter versioning → /resource?version=1
Header-based versioning → Accept: application/vnd.company.v1+json
Content negotiation versioning → Embed in media type.

Example (Header-based):

Accept: application/vnd.myapi.v2+json

4. Keep Version Naming Short and Clear

Avoid overly descriptive version strings - the API docs should describe the changes, not the version name.

Bad:

/v1_release_candidate_final/users

Good:

/v1/users

5. Use Sequential Numbers

Do not skip version numbers unless there’s a clear release reason (e.g., internal version dropped for stability reasons).

Version Naming by Strategy

A. URI Versioning

Most visible and easy to cache.

GET /v1/customers
GET /v2/customers

Good for: Public APIs, long-term support. Bad for: Clients that need frequent upgrades - changing URIs breaks bookmarks and code.

B. Query Parameter Versioning

GET /customers?version=1

Good for: Prototyping, quick changes. Bad for: Cache efficiency - versions may get mixed in caches.

C. Header Versioning

GET /customers
Accept: application/vnd.company.v1+json

Good for: Clean URIs, enterprise APIs. Bad for: Less discoverable, requires good documentation.

D. Media Type Versioning

Accept: application/vnd.mycompany.orders-v2+json

Good for: Highly structured APIs with many data formats. Bad for: Complexity - can confuse new developers.