---
title: "Versioning · API docs · CheckAnySite"
description: "The API version is in the path. Within v1 we only add fields, values and codes; we never remove or rename them."
url: "https://docs.checkanysite.com/versioning"
---

Concepts

# Versioning

The API version is in the path. Within v1 we only add fields, values and codes; we never remove or rename them.

## The version in the path

The version is part of every endpoint’s path: `https://api.checkanysite.com/v1`. A change that would break existing clients comes as a new version alongside v1, never within it.

## What can change

- We may add fields, enum values and error codes, so your code should ignore ones it doesn’t know.
- We don’t remove or rename anything without the notice described below.
- The machine-readable description, [openapi.json](https://api.checkanysite.com/v1/openapi.json), is built from the same definitions as these pages, so the two always match.

## Deprecations

We announce anything we retire from v1 at least 6 months before it stops working, in two places:

- On the [changelog](https://checkanysite.com/changelog), in an entry marked API that says what changes, from when, and what to use instead.
- On every response it affects: a `Deprecation` header (RFC 9745) with the date it was deprecated, and a `Sunset` header (RFC 8594) with the date it stops working.

```text Headers on a deprecated response
Deprecation: @1798761600
Sunset: Thu, 01 Jul 2027 00:00:00 GMT
```

Log these headers alongside your errors, so a retirement never takes you by surprise.

## Signature and score versions

What we detect improves over time, so each result names the signature list and score formula that produced it, in `versions`. The current versions are signatures 0.6.1 and score 1.1. The [changelog](https://checkanysite.com/changelog) lists what each version changed, including our mistakes.