---
title: "/2026-01/marketing-solutions/audiences/estimate-size"
method: POST
path: "/2026-01/marketing-solutions/audiences/estimate-size"
tags: ["Audience"]
---

# /2026-01/marketing-solutions/audiences/estimate-size

`POST /2026-01/marketing-solutions/audiences/estimate-size`

## Request

- Base URL: `https://api.criteo.com`
- URL: `https://api.criteo.com/2026-01/marketing-solutions/audiences/estimate-size`
- Auth: OAuth 2
  - Authorization code: `https://api.criteo.com/oauth2`
  - Client credentials
  - Token URL: `https://api.criteo.com/oauth2/token` scopes: `MarketingSolutions_Audience_Manage`
- TypeScript: <https://skmtc.dev/criteo/apis/criteo-api/docs/2026-01/marketing-solutions/audiences/estimate-size/post.ts> (a function with typed inputs; its response is checked against the schema)

Gets the size estimation of a non existent audience. An error is returned when size calculation is not supported.

## Request body

- AudienceEstimateSizeInputV1: Input to estimate the size of an audience.
  - `data` AudienceEstimateSizeEntityV1Resource: A top-level object that encapsulates a Criteo API response for a single value
    - `attributes` AudienceEstimateSizeEntityV1: Audience of people of interest for a marketer.
      - `advertiserId` string, required: Advertiser associated to the audience
      - `algebra` AlgebraNodeV1, nullable, required: Node in the audience algebra definition.
        - `and` AlgebraNodeV1[], nullable
        - `audienceSegmentId` string, nullable
        - `not` AlgebraNodeV1 (recursive)
        - `or` AlgebraNodeV1[], nullable
    - `type` string

## Response `200`

Success or partial success

- AudienceSizeEstimationV1Response: A top-level object that encapsulates a Criteo API response for a single value
  - `data` AudienceSizeEstimationV1Resource, nullable: A top-level object that encapsulates a Criteo API response for a single value
    - `attributes` AudienceSizeEstimationV1, nullable: Audience size estimation
      - `size` integer, nullable
    - `type` string, nullable
  - `errors` CommonProblem[], nullable
    - `code` string, nullable: A machine-readable error code, expressed as a string value.
    - `detail` string, nullable: A human-readable explanation specific to this occurrence of the problem
    - `instance` string, nullable: A URI that identifies the specific occurrence of the problem.
    - `source` object, nullable: A machine-readable structure to reference to the exact location(s) causing the error(s)
    - `stackTrace` string, nullable
    - `title` string, nullable: A short human-readable description of the problem type
    - `traceId` string, nullable: The request correlation ID this problem comes from.
    - `traceIdentifier` string, nullable: The request correlation ID this problem comes from. (deprecated, use traceId instead)
    - `type` 'unknown' | 'access-control' | 'authentication' | 'authorization' | 'availability' | 'deprecation' | 'quota' | 'validation', nullable: The problem's category.
  - `warnings` CommonProblem[], nullable
    - `code` string, nullable: A machine-readable error code, expressed as a string value.
    - `detail` string, nullable: A human-readable explanation specific to this occurrence of the problem
    - `instance` string, nullable: A URI that identifies the specific occurrence of the problem.
    - `source` object, nullable: A machine-readable structure to reference to the exact location(s) causing the error(s)
    - `stackTrace` string, nullable
    - `title` string, nullable: A short human-readable description of the problem type
    - `traceId` string, nullable: The request correlation ID this problem comes from.
    - `traceIdentifier` string, nullable: The request correlation ID this problem comes from. (deprecated, use traceId instead)
    - `type` 'unknown' | 'access-control' | 'authentication' | 'authorization' | 'availability' | 'deprecation' | 'quota' | 'validation', nullable: The problem's category.

---

[API](https://skmtc.dev/criteo/apis/criteo-api.md) - [All operations](https://skmtc.dev/criteo/apis/criteo-api/llms.txt) - [OpenAPI document](https://skmtc.dev/criteo/apis/criteo-api/revisions/c1721589426a?raw)