> ## Documentation Index
> Fetch the complete documentation index at: https://docs.engine.usesophic.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Versioning

> Learn about our versioning policy.

Our API is versioned using date-based versioning. The API version name is
based on the date when the API version was released. For example, the API version
`2026-01-01` was released on January 1, 2026.

## Current version

The current API version is **2026-01-01**.

## Specifying a version

Specify the API version using the `Api-Version` header:

```shell theme={"theme":"catppuccin-mocha"}
curl https://api.engine.usesophic.com/me \
  -H "Authorization: Bearer BEARER_TOKEN" \
  -H "Api-Version: 2026-01-01"
```

## Backwards compatible changes

The following changes are considered backwards compatible and will be available in all
supported API versions without requiring a version change:

* Adding new API resources
* Adding new optional request parameters to existing API methods
* Adding new properties to existing API responses
* Changing the order of properties in existing API responses
* Changing the length or format of opaque strings, such as resource IDs, error messages,
  and other human-readable strings (including adding or removing ID prefixes)
* Adding new event types
* Adding new enum values (so your integration must handle unknown values)
* Adding new error codes
* Changing the wording, formatting, or language of error `detail` messages

## Breaking changes

Any breaking changes will be released in a new API version. Breaking changes are changes
that can potentially break a well-written integration, including:

* Removing an entire operation
* Removing or renaming a parameter
* Removing or renaming a response field
* Removing or changing the meaning of an existing error code
* Adding a new required parameter
* Making a previously optional parameter required
* Changing the type of a parameter or response field
* Removing enum values
* Adding a new validation rule to an existing parameter
* Changing authentication or authorization requirements
* Changing the behavior or semantics of an operation (including sorting, pagination,
  rounding, idempotency, side effects, etc.)

## Version support policy

When a new REST API version is released, the previous API version will be supported for
at least **4 more months** following the release of the new API version. If your integration
is using a deprecated version, you will be notified by email, and our responses will include
a sunset header (`Api-Version-Sunset: <sunset date>`) containing the date that the version
you are using will be sunset.