The Change Customer Test and Control Group API lets you manually move a customer between two groups — the TEST group and the CONTROL group.

Here is what these groups mean: when a brand runs a campaign, not every customer receives it. Capillary's Engage+ platform automatically divides customers into two groups. Customers in the TEST group receive the campaign communications — emails, SMS, and offers. Customers in the CONTROL group receive nothing. This division exists so brands can compare the behaviour of both groups after the campaign and measure whether the communication actually drove any results.

This division is based on two values assigned to every customer:

Score — A number between 1 and 100 that is automatically assigned to a customer when they are first registered into the Test & Control system.
Test Ratio — A number between 1 and 100 configured at the organisation level. It represents the percentage of customers who should receive campaign communications. For example, a test ratio of 70 means 70% of customers are in the TEST group and 30% are in the CONTROL group.

The logic is simple: if a customer's score is less than or equal to the test ratio, they are in the TEST group and will receive campaigns. If their score is greater than the test ratio, they are in the CONTROL group and will not receive anything.

Now, while this division happens automatically, there are times when a brand needs to move a specific customer from one group to the other. For example, a support agent may need to ensure a particular customer starts receiving campaigns, or a brand may want to exclude a specific customer from all communications. This API reads the customer's current group and moves them to the opposite one — if the customer is in the TEST group, they are moved to CONTROL, and if they are in the CONTROL group, they are moved to TEST.

Example: A brand runs a holiday sale campaign offering 20% off to all customers in the TEST group. A loyal customer contacts support saying they never received the offer. The support agent checks the customer's group and finds they were automatically placed in the CONTROL group — meaning they were excluded from the campaign. The agent calls this API to move the customer to the TEST group so they start receiving campaign communications going forward.

Example request

curl --location --request PUT \
  'https://{host}/v2/tnc/change/customers/{customerId}' \
  --header 'Authorization: Basic {base64_encoded_credentials}'

Prerequisites

Requires access to the Customer API access group.
The customer must already have a Test & Control score assigned. Use the Assign Customer to Test and Control Group API first if the customer has never been assigned.

Path parameters

Field	Type	Required	Description
`customerId`	Long	Yes	Unique internal ID of the customer whose Test and Control group needs to be changed.

Request body

This endpoint does not require a request body.

API Quick Reference

PUT /v2/tnc/change/customers/{customerId}

Response
   └─ root (object)
       ├─ SCORE       (number)
       └─ TEST_RATIO  (number)

Example response

Customer moved to TEST group

{
  "SCORE": 0,
  "TEST_RATIO": 95
}

Customer moved to CONTROL group

{
  "SCORE": 101,
  "TEST_RATIO": 95
}

Response parameters

Field	Type	Description
`SCORE`	Integer	The customer's updated score after the group change. Returns `0` if the customer was moved to the TEST group, and `101` if the customer was moved to the CONTROL group.
`TEST_RATIO`	Integer	The organisation's configured test ratio. Represents the percentage of customers in the TEST group. If `SCORE` is less than or equal to `TEST_RATIO`, the customer is in the TEST group. If `SCORE` is greater than `TEST_RATIO`, the customer is in the CONTROL group.

Error and warning codes

Code	Type	Description
400	Error	Request is malformed — verify that the `customerId` path parameter is a valid numeric value.
401	Error	Missing or invalid `Authorization` header. Provide valid Basic Auth credentials.
500	Error	Internal server error. Retry the request after a short delay.