CommetCommet
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Adjust balance POSTApply an Offer to a subscription PUTCancel subscription POSTChange plan POSTCreate a recovery payment link for a past due subscription POSTCreate subscription POSTGet active subscription GETGet subscription by ID GETList subscriptions GETPause subscription POSTPreview plan change POSTReactivate a past due or canceled subscription POSTRemove an Offer from a pending checkout DELETEResume subscription POSTRevoke scheduled pause DELETETop up balance POSTRevert scheduled cancellation POSTUpdate payment method POSTUpdate subscription pause PATCH
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Change plan

Upgrade or change billing interval immediately, optionally applying an Offer. Scheduled changes do not accept offers.

POST
/subscriptions/{id}/change-plan

Upgrade or change billing interval immediately, optionally applying an Offer. Scheduled changes do not accept offers.

Authorization

ApiKeyAuth
x-api-key<token>

In: header

Path Parameters

id*string

Header Parameters

Idempotency-Key?string

Unique key used to safely retry this write for 24 hours without applying it twice.

Length1 <= length <= 200

Request Body

application/json

TypeScript Definitions

Use the request body type in TypeScript.

Response Body

application/json

application/json

application/json

application/json

application/json

application/json

application/json

application/json

application/json

application/json

curl -X POST "https://example.com/subscriptions/string/change-plan" \  -H "Content-Type: application/json" \  -d '{}'
{  "outcome": "requires_checkout",  "requiresCheckout": true,  "checkoutUrl": "https://commet.co/checkout/example_plan_change_token",  "object": "plan_change",  "livemode": false}
{  "error": {    "type": "validation_error",    "code": "validation_error",    "message": "The request contains an invalid parameter.",    "doc_url": "https://commet.co/docs/api-reference/2026-08-27/errors/validation_error.md"  }}
{  "error": {    "type": "authentication_error",    "code": "unauthorized",    "message": "A valid API key is required.",    "doc_url": "https://commet.co/docs/api-reference/2026-08-27/errors/unauthorized.md"  }}
{  "error": {    "type": "billing_error",    "code": "payment_failed",    "message": "The payment could not be completed.",    "doc_url": "https://commet.co/docs/api-reference/2026-08-27/errors/payment_failed.md"  }}
{  "error": {    "type": "authentication_error",    "code": "forbidden",    "message": "You do not have permission to perform this operation.",    "doc_url": "https://commet.co/docs/api-reference/2026-08-27/errors/forbidden.md"  }}
{  "error": {    "type": "not_found_error",    "code": "not_found",    "message": "The requested resource was not found.",    "doc_url": "https://commet.co/docs/api-reference/2026-08-27/errors/not_found.md"  }}
{  "error": {    "type": "conflict_error",    "code": "idempotency_in_progress",    "message": "A request with this idempotency key is still being processed.",    "doc_url": "https://commet.co/docs/api-reference/2026-08-27/errors/idempotency_in_progress.md"  }}
{  "error": {    "type": "rate_limit_error",    "code": "rate_limited",    "message": "Too many requests. Retry after the interval specified in the Retry-After header.",    "doc_url": "https://commet.co/docs/api-reference/2026-08-27/errors/rate_limited.md"  }}
{  "error": {    "type": "internal_error",    "code": "internal_error",    "message": "An unexpected error occurred while processing the request.",    "doc_url": "https://commet.co/docs/api-reference/2026-08-27/errors/internal_error.md"  }}
{  "error": {    "type": "internal_error",    "code": "idempotency_unavailable",    "message": "Idempotency storage is temporarily unavailable. Retry with the same idempotency key.",    "doc_url": "https://commet.co/docs/api-reference/2026-08-27/errors/idempotency_unavailable.md"  }}

Cancel subscription POST

Cancel immediately or at period end and return the updated subscription.

Create a recovery payment link for a past due subscription POST

Generates a hosted, signed recovery link that lets the customer pay the outstanding renewal charge for a past_due subscription. Unlike reactivate, which charges server-to-server, this returns a link the merchant can deliver through their own email, SMS, or dashboard. The link carries a self-contained signed token and stays valid until the charge is paid or the subscription is no longer past due.

newPlanId?string
Length1 <= length
newBillingInterval?string

Value in

  • "weekly"
  • "monthly"
  • "quarterly"
  • "yearly"
successUrl?string
Formaturi
offerId?string
Length1 <= length