Creates a subscription payment for a recurring product (frequencyInDays is set).
Returns a checkout URL to redirect your customer to.
For custom price products (isCustomPrice: true), provide priceCents and currency.
One-time products? Use
POST /api/payment/createinstead.
Documentation Index
Fetch the complete documentation index at: https://documentation.suby.fi/llms.txt
Use this file to discover all available pages before exploring further.
API key authentication
ID of a subscription product
"pro_sub456"
"customer@example.com"
Customer first name. Used to prefill checkout fields.
100"John"
Customer last name. Used to prefill checkout fields.
100"Doe"
Price in cents as a string.
Required when the product has isCustomPrice: true. Must NOT be provided for fixed-price products.
This price is locked for all future renewals.
"999"
Currency for the price. Required when priceCents is provided, ignored otherwise.
USD, EUR 255"sub_ref_001"
Extra fields shown on the checkout page to collect information from the customer
(e.g. Discord username, referral source, terms acceptance).
Fields are collected on the initial checkout only — renewal payments do not
re-prompt the customer. The initial payment webhook carries the responses in
context.customFieldsResponse; renewal webhooks have it set to null.
Maximum 10 fields per subscription.
10