Update test cohort

Deprecated. This page documents the v2 buyer API, which is closed to new API clients and switches off on 1 December 2026. Use V3 instead: see Move a v2 buyer REST integration to V3. The conversion endpoint, Log event, stays open.

PUT /api/v2/buyer/advertisers/{advertiserId}/test-cohorts/{cohortId} Updates an existing test cohort. All body fields are optional — send only what you want to change; omitted fields keep their current values.

Request

curl -X PUT https://api.apostra.com/api/v2/buyer/advertisers/12345/test-cohorts/cohort_abc123 \
  -H "Authorization: Bearer $SCOPE3_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "West Coast Treatment Group - Updated",
    "definition": {
      "type": "geo_region",
      "regions": ["US-CA", "US-OR", "US-WA", "US-NV"]
    },
    "estimatedSize": 62000
  }'

Parameters

Field	Type	Required	Notes
`advertiserId`	string	Yes	Path parameter — the owning advertiser
`cohortId`	string	Yes	Path parameter — the cohort ID
`name`	string	No	Cohort label (max 255)
`description`	string	No	Free-text description (max 1000)
`cohortType`	string	No	Free-form classification
`role`	enum	No	`TREATMENT`, `CONTROL`, `OBSERVATION`
`definition`	object	No	Targeting definition. `type` is required; additional fields vary by type
`estimatedSize`	integer	No	Size estimate for power analysis

Response

{
  "id": "cohort_abc123",
  "advertiserId": "12345",
  "name": "West Coast Treatment Group - Updated",
  "description": null,
  "cohortType": "geographic",
  "role": "TREATMENT",
  "definition": { "type": "geo_region", "regions": ["US-CA", "US-OR", "US-WA", "US-NV"] },
  "estimatedSize": 62000,
  "isActive": true,
  "createdAt": "2026-01-15T10:30:00Z",
  "updatedAt": "2026-03-20T14:45:00Z"
}

Returns the full cohort after the update.

Errors

400 VALIDATION_ERROR — invalid role or a definition missing its type.
404 NOT_FOUND — cohortId (or advertiserId) does not exist or is not visible to the authenticated account.

See Errors for the full error contract.

Measurement tasks

All measurement operations

Measurement overview

Pipeline, belief state, and concepts

Get test cohort

Read the current cohort

Start building

Core Concepts

Buyer operations

Seller operations

Cross-Cutting Reference

Buyer API reference

Seller API reference

Release Notes

Update test cohort

Request

Parameters

Response

Errors

Measurement tasks

Measurement overview

Get test cohort

​Request

​Parameters

​Response

​Errors

​Related

Measurement tasks

Measurement overview

Get test cohort

Request

Parameters

Response

Errors

Related