Create an installment payment plan
Creates an installment payment plan for a customer account, optionally
linked to an order. Installments and auto-charge settings are part of the
request body. Requires payments:write scope. Idempotent via the
Idempotency-Key header.
Authorizations
API key issued per entity via Settings > Developers > API Keys.
Each key carries scopes (e.g. orders:read, products:write).
Bearer token format: Authorization: Bearer ark_live_ent_
Test keys use ark_test_ent_. Both are issued per entity
via Settings > Developers > API Keys.
Headers
Client-generated unique key for idempotent POST/PATCH/DELETE operations. Max 255 chars. On retry with the same key, the original response is returned without re-executing the operation. Keys expire after 24 hours. Pattern: or --.
255Body
Customer account the plan bills.
Total amount the plan covers.
Optional order the plan settles.
Stored payment method for auto-charge.
Installment schedule (sequence, amount, due_date).
Response
Payment plan created.
An installment payment plan for a customer account, optionally linked to an order. Mirrors public.payment_plans.
payment_plan active, completed, cancelled Installment schedule rows when expanded.

