Overview

Add a new member to a group subscription. The subscription must have available seats for the new member.

Example: Add a new employee to a corporate subscription when they join the company.

Conditional Requirements

Condition	Required Fields
Always	`subscription_id`, `customer_id`
Subscription must be	A valid membership-type subscription on the current site
Customer must not be	Already a member of the same subscription
Subscription must have	Available member seat capacity

Validation Constraints

Field	Constraint
`customer_id`	Must exist under the current site and account
`customer_id`	Must not already be a member of the subscription (unique per subscription)
`customer_id`	Subject to the subscription's `member_seat_capacity` limit
`subscription_id`	Must reference a membership-type subscription
`address_id`	Must belong to the specified customer (validated via `exists:address,id,user_id,{customer_id}`)
`old_provider_id`	Must be unique per account

Pending Member Activation

If a pending invitation already exists for the customer's email on this subscription, the store endpoint activates that pending membership instead of creating a new one. In this case, the response returns 200 OK instead of 201 Created.

201Created.

400Validation error.

401Unauthenticated.