> This page is for version v2025-04-21.
> 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.

# Create Evaluation Set

POST https://api.extend.ai/evaluation_sets
Content-Type: application/json

Evaluation sets are collections of files and expected outputs that are used to evaluate the performance of a given processor in Extend. This endpoint will create a new evaluation set in Extend, which items can be added to using the [Create Evaluation Set Item](https://docs.extend.ai/2025-04-21/developers/api-reference/evaluation-set-endpoints/create-evaluation-set-item) endpoint.

Note: it is not necessary to create an evaluation set via API. You can also create an evaluation set via the Extend dashboard and take the ID from there.


Reference: https://docs.extend.ai/2025-04-21/developers/api-reference/evaluation-set-endpoints/create-evaluation-set

## Authentication

- `Authorization` header (bearer token, required) — Bearer authentication of the form `Bearer <token>`, where token is your auth token.

## Request

### Headers

- `x-extend-api-version` ("2025-04-21", optional, default: 2025-04-21) — API version to use for the request. If you do not specify a version, you will either receive a `400 Bad Request` or be set to a previous legacy version. See [API Versioning](https://docs.extend.ai/2025-04-21/developers/api-versioning) for more details.

### Body (application/json)

This endpoint expects an object.

- `name` (string, required) — The name of the evaluation set. Example: `"Invoice Processing Test Set"`
- `description` (string, required) — A description of what this evaluation set is used for. Example: `"Q4 2023 vendor invoices"`
- `processorId` (string, required) — The ID of the processor to create an evaluation set for. Evaluation sets can in theory be run against any processor, but it is required to associate the evaluation set with a primary processor. Example: `"dp_Xj8mK2pL9nR4vT7qY5wZ"`

## Response

### 200

Successfully created evaluation set

- `success` (boolean, required)
- `evaluationSet` (EvaluationSet, required) — The EvaluationSet object represents an evaluation set in Extend. Evaluation sets are collections of files and expected outputs that are used to evaluate the performance of a given processor in Extend.

## Errors

### 400 Bad Request Error

Bad Request

- `success` (boolean, optional)
- `error` (string, optional) — Error message

### 401 Unauthorized Error

Unauthorized

- `success` (boolean, optional)
- `error` (string, optional) — Error message

## Types

### EvaluationSet

The EvaluationSet object represents an evaluation set in Extend. Evaluation sets are collections of files and expected outputs that are used to evaluate the performance of a given processor in Extend.

- `object` (string, required) — The type of response. In this case, it will always be `"evaluation_set"`.
- `id` (string, required) — The ID of the evaluation set. Example: `"ev_2LcgeY_mp2T5yPaEuq5Lw"`
- `name` (string, required) — The name of the evaluation set. Example: `"Invoice Processing Test Set"`
- `description` (string, required) — A description of the evaluation set. Example: `"Q4 2023 vendor invoices for accuracy testing"`
- `processorId` (string, required) — The ID of the processor associated with this evaluation set. Example: `"dp_Xj8mK2pL9nR4vT7qY5wZ"`
- `createdAt` (string, required) — The time (in UTC) at which the evaluation set was created. Will follow the RFC 3339 format. Example: `"2024-03-21T15:30:00Z"`
- `updatedAt` (string, required) — The time (in UTC) at which the evaluation set was last updated. Will follow the RFC 3339 format. Example: `"2024-03-21T16:45:00Z"`

## Examples

**Request**

```json
{
  "name": "My Evaluation Set",
  "description": "My Evaluation Set Description",
  "processorId": "processor_id_here"
}
```

**Response**

```json
{
  "success": true,
  "evaluationSet": {
    "object": "evaluation_set",
    "id": "ev_2LcgeY_mp2T5yPaEuq5Lw",
    "name": "Invoice Processing Test Set",
    "description": "Q4 2023 vendor invoices for accuracy testing",
    "processorId": "dp_Xj8mK2pL9nR4vT7qY5wZ",
    "createdAt": "2024-03-21T15:30:00Z",
    "updatedAt": "2024-03-21T16:45:00Z"
  }
}
```