---
title: "Start an audience size job"
method: POST
path: "/models/{modelId}/size"
---

# Start an audience size job

`POST /models/{modelId}/size`

## Request

- Base URL: `https://api.hightouch.com/api/v1`
- URL: `https://api.hightouch.com/api/v1/models/{modelId}/size`
- Auth: HTTP bearer

Start a background job to compute audience size.

## Path parameters

- `modelId` number, double, required

## Response `200`

Ok

- union
  - StartAudienceSizeJobOutput
    - `jobId` string, required
  - ValidateErrorJSON
    - `message` 'Validation failed', required
    - `details` object, required
  - 'Internal Server Error'

## Other responses

- `401`: Unauthorized
- `403`: Forbidden
- `404`: Not Found
- `422`: Validation Failed
- `500`: Something went wrong

## Changes

- **2026-09-16** `8cbdd0fc09d2`: 1 info
  - endpoint added

[Operation history](https://skmtc.dev/hightouch/apis/hightouch-api/changes/models/:modelId/size/post.md)

---

[API](https://skmtc.dev/hightouch/apis/hightouch-api.md) - [All operations](https://skmtc.dev/hightouch/apis/hightouch-api/llms.txt) - [OpenAPI document](https://skmtc.dev/hightouch/apis/hightouch-api/revisions/7f9793951e4f?raw)