> This page is for version v2024-12-23.
> For other versions, use one of these documentation indexes:
> - v2026-02-09 (default): https://docs.extend.ai/2026-02-09/llms.txt
> - v2025-04-21: https://docs.extend.ai/2025-04-21/llms.txt
> - v2024-12-23: https://docs.extend.ai/2024-12-23/llms.txt

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.extend.ai/llms.txt
> Use this file to discover all available pages before exploring further.
>
> ## API version
> The current API version is `2026-02-09`, served at the site root (no version prefix in URLs).
> If this page URL contains `/2025-04-21/` or `/2024-12-23/`, you are reading an older API version.
> Prefer the current docs at https://docs.extend.ai/llms.txt unless the user explicitly needs that older version.
> Do not treat older-version pages as the source of truth for new integrations.

# API Versioning

## Overview

The Extend API uses versioning to ensure that your integration remains stable as we evolve our API. The version is specified using the `x-extend-api-version` header in your requests.

## Backwards-compatible Changes

We consider the following changes to be backwards-compatible:

1. Adding new APIs
2. Adding new optional request parameters to existing APIs
3. Adding new properties to existing API responses

## Specifying a Version

To specify an API version, include the `x-extend-api-version` header in your requests.

The API version is specified in the format `YYYY-MM-DD` and corresponds to the date of the release that introduced the breaking changes.

```curl
curl -X POST https://api-prod.extend.app/workflow_runs \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "x-extend-api-version: 2025-04-21" \
-H "Content-Type: application/json" \
-d '{ ... }'
```

*Important*: If you don't specify a version:

* When using an API key made before April 21, 2025, you'll automatically use the legacy version (`2024-12-23`)
* When using an API key made after April 21, 2025, you will receive an error and be required to specify an API version.
* Some organizations may default to a legacy version for backward compatibility predating the introduction of the `x-extend-api-version` header. Reach out to the Extend team if you need to change this.

*Note: The `v1` prefix on the routes is legacy and will be deprecated in the future. We recommend specifying the version using the `x-extend-api-version` header.*

## Webhook Endpoints

When you create a webhook endpoint in the Extend dashboard, you will be prompted to select the API version you'd like to use. All webhook notifications sent to that endpoint will include the same API version in the `x-extend-api-version` header, ensuring consistency in payload formats.

We strongly recommend keeping the versions defined on your webhook endpoint in sync with the version specified in your requests.

## API Version Changelog

| Version      | Status  | Release Date      | Changes                                                                                                                                                                                                                                                                                     |
| ------------ | ------- | ----------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `2025-04-21` | Current | April 21, 2025    | Exposed more granular control to several endpoints that use processor configurations. Breaking changes for the processor config schema. Also changes the splitter output shape slightly. [See our migration guide for details.](/2024-12-23/developers/migrating-to-2025-04-21-api-version) |
| `2024-12-23` | Legacy  | December 23, 2024 | Minor, backwards incompatible change: excel files now have their own file type EXCEL and data output shape that is distinct from CSVs. To migrate to new API version, if you are consuming the parsed data from all file types make sure to begin handling EXCEL separately.                |
| `2024-11-14` | Legacy  | November 14, 2024 | Significant, backwards incompatible change: New processor config format which is not fully backwards compatible with `"2024-07-30"`. See [here](/2024-12-23/developers/guides/processor-configs) for new processor config schema.                                                           |
| `2024-07-30` | Legacy  | July 30, 2024     | Added support for webhook event subscriptions plus a suite of new endpoints for managing processors. And fully deprecated the legacy snake case `workflow_run` keys in favor of camel case.                                                                                                 |
| `2024-02-01` | Legacy  | February 1, 2024  | Initial API version with support for workflows.                                                                                                                                                                                                                                             |