> ## Documentation Index
> Fetch the complete documentation index at: https://developer.kalixo.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Versioning

> How the API and event payloads evolve.

The current API version is `2026-10-01`. Every event carries it in `api_version`.

Kalixo makes **additive** changes without a new version: new endpoints, new optional
request fields, new response fields, new event types, new enum values (for example a
new `decline_code` or payment method `type`). Build your integration to ignore unknown
fields and event types.

Breaking changes (removing or renaming fields, changing meanings) ship only with a new
API version, announced in the [changelog](https://developer.kalixo.io/checkout/changelog.md) at least six months ahead.

Kalixo.js follows semantic versioning on `https://js.kalixo.io/v1/`. The `v1` path always
serves the latest compatible release.


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