Mid-cycle plan proration API

Computes the unused credit on the old plan and the prorated charge for the new plan over the remaining days of a billing cycle, netting to an immediate charge or credit. Answers 'What do I owe for a mid-cycle upgrade?', 'How much credit for a downgrade?'.

Price$0.02per request

MethodPOST

Route/v1/commerce/subscription-proration

StatusLive

MIME typeapplication/json

Rate limit120/minute

Cache0s public

commercesubscriptionprorationsaasupgradedowngradebillingmid-cycle

API URLhttps://x402.hexl.dev/v1/commerce/subscription-proration

Integration docs

Example request

{
  "oldPlanPrice": 30,
  "newPlanPrice": 90,
  "cycleDays": 30,
  "daysRemaining": 20
}

Example response

{
  "oldPlanPrice": 30,
  "newPlanPrice": 90,
  "cycleDays": 30,
  "daysRemaining": 20,
  "prorationFraction": 0.6667,
  "unusedCreditFromOldPlan": 20,
  "proratedNewPlanCharge": 60,
  "netAmountDue": 40,
  "direction": "upgrade",
  "chargeOrCredit": "charge",
  "interpretation": "Charge $40 now (prorated $60 for new plan, less $20 unused credit)."
}

Input schema

{
  "type": "object",
  "required": [
    "oldPlanPrice",
    "newPlanPrice",
    "cycleDays",
    "daysRemaining"
  ],
  "properties": {
    "oldPlanPrice": {
      "type": "number",
      "examples": [
        30
      ]
    },
    "newPlanPrice": {
      "type": "number",
      "examples": [
        90
      ]
    },
    "cycleDays": {
      "type": "integer",
      "examples": [
        30
      ]
    },
    "daysRemaining": {
      "type": "integer",
      "examples": [
        20
      ]
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}