---
title: "API versioning and deprecation · Daniel Farina"
description: "Agent harnesses, evals, and the layer around the model."
canonical: https://danielfarina.com/developers/versioning/
last-updated: "2026-08-30"
---

# API versioning and deprecation · Daniel Farina

Source: https://danielfarina.com/developers/versioning/

# API versioning and deprecation

This is the deprecation policy for the danielfarina.com public API. Agents can treat it as stable documentation. Canonical URL: [https://danielfarina.com/developers/versioning](https://danielfarina.com/developers/versioning).

## Versioning

Breaking changes require a new major URL path. Current major: `/api/v1`. The `API-Version: v1` response header repeats that. OpenAPI field `x-api-lifecycle.current_major_version` is `v1`.

## Deprecation and Sunset headers

When an operation is deprecated we send RFC 9745 `Deprecation` (HTTP-date) and `Sunset` (HTTP-date) headers, and a `Link` with `rel="deprecation"` pointing at this page. Notice is at least 90 days before removal. v1 has no scheduled sunset.

## Non-breaking changes

Additive JSON fields, new GET paths under `/api/v1`, and new optional headers are not deprecations. Clients must ignore unknown fields.