API Versioning & LTS Policy

Versioning Scheme

qr3.app uses URL-based versioning: /v1/, /v2/, etc.

https://qr3.app/v1/codes
                    ^^^
                    Version prefix

The current stable version is v1 LTS .

Version Lifecycle

New         → Stable (LTS) → Maintenance → End-of-Life
 Beta phase    Active           Fixes only    Discontinued
 (0–3 months)  (12+ months)     (6 months)    (after)

Version	Status	Support until	Notes
v1	✅ Stable (LTS)	Min. March 2027	Current production version
v2	📋 Planned	—	Roadmap: Phase 5+

Breaking vs. Non-Breaking Changes

Non-breaking (no version bump)

Adding new optional request fields
Adding new response fields
New endpoints
New enum values for existing fields
Performance improvements
Bug fixes

Breaking (new major version)

Removing or renaming fields
Changing field types
Changing status codes
Removing endpoints
Changing authentication scheme

Deprecation Notice

Deprecated endpoints send response headers:

HTTP/1.1 200 OK
Deprecation: true
Sunset: Sat, 01 Mar 2027 00:00:00 GMT
Link: <https://docs.qr3.app/en/api/versioning>; rel="deprecation"

LTS Guarantees (v1)

For the current LTS version v1:

No breaking changes during the LTS period
Security fixes within 72 hours
Bug fixes within 14 days
Advance notice of at least 6 months before End-of-Life
Migration guides published before v2 GA

Changelog

Changes are documented in the API response:

GET /v1/changelog

For detailed release notes, see the Versioning Guide.

Contact

Questions about the API lifecycle? Email [email protected].