* https://sendgrid.com/docs/ui/account-and-settings/billing/ * https://www.programmableweb.com/category/billing/api * https://shopify.dev/docs/admin-api/rest/reference/billing * https://developers.docusign.com/esign-rest-api/reference/Billing/ * https://docs.fastly.com/api/account * https://developer.akamai.com/api/core_features/invoicing/v2.html * https://ideas.digitalocean.com/ideas/DO-I-2318