# Versioning

The version is part of every path: `/v1/...`. Version 1 is used by the PROradius web and mobile apps as well as by
integrations, so it only ever receives **additive** changes.

## What can change in v1

- New endpoints.
- New optional request fields and query parameters.
- New fields in responses.
- New webhook topics and new fields in webhook payloads.

## What never changes in v1

- Existing fields keep their name, type and meaning.
- Existing endpoints are not removed.
- A request that works today keeps working.

## Write tolerant clients

- Ignore response fields you do not know.
- Do not fail on unknown values in string fields such as `status` or `created_via`; treat them as "other".
- Do not depend on the order of keys in JSON objects.

## Webhook payload version

Each webhook endpoint is stamped with a payload version (`api_version`, currently `2026-09-01`) when you create it.
Every delivery carries it in the envelope. The stamp lets a payload evolve later without breaking endpoints that
already exist.

## Changes

New fields and endpoints are listed in the [Changelog](/changelog/).