Installment / BNPL schedule API

Generates an even installment / BNPL payment calendar (e.g. Pay-in-4) with an optional down payment and finance fee, fixing the final payment for penny rounding and reporting cost of credit. Answers 'What is my Pay-in-4 schedule?', 'What is the cost of credit?'.

Price$0.02per request

MethodPOST

Route/v1/commerce/installment-schedule

StatusLive

MIME typeapplication/json

Rate limit120/minute

Cache0s public

commerceinstallmentbnplpay-in-4financingschedulepayment-plancheckout

API URLhttps://x402.hexl.dev/v1/commerce/installment-schedule

Integration docs

Example request

{
  "principal": 100,
  "installments": 4
}

Example response

{
  "principal": 100,
  "installments": 4,
  "intervalDays": 14,
  "downPayment": 0,
  "financeFee": 0,
  "financeFeePct": 0,
  "totalRepayable": 100,
  "costOfCredit": 0,
  "schedule": [
    {
      "payment": 1,
      "label": "installment 1",
      "dueDay": 0,
      "amount": 25
    },
    {
      "payment": 2,
      "label": "installment 2",
      "dueDay": 14,
      "amount": 25
    },
    {
      "payment": 3,
      "label": "installment 3",
      "dueDay": 28,
      "amount": 25
    },
    {
      "payment": 4,
      "label": "installment 4",
      "dueDay": 42,
      "amount": 25
    }
  ],
  "interpretation": "4 payments of ~$25 every 14 days; total repayable $100 (cost of credit $0)."
}

Input schema

{
  "type": "object",
  "required": [
    "principal",
    "installments"
  ],
  "properties": {
    "principal": {
      "type": "number",
      "examples": [
        100
      ]
    },
    "installments": {
      "type": "integer",
      "examples": [
        4
      ]
    },
    "intervalDays": {
      "type": "integer",
      "examples": [
        14
      ]
    },
    "financeFeePct": {
      "type": "number",
      "examples": [
        0
      ]
    }
  }
}

Output schema

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