API Integration Guide

This guide covers everything a funder's development team needs to integrate with FoxCalc — from authentication to going live.

Overview

FoxCalc exposes a REST API for funders to create, update, and revoke offers. When an ISO submits their configured terms through the calculator, FoxCalc sends the submission back to the funder via a callback webhook.

Base URL: https://app.rbfoffercalc.com

Integration Flow

1. Authenticate — Send requests with API Key + HMAC signature
2. Create an offer — POST /api/v1/{funder}/offers with deal parameters
3. Share the calculator URL — Send the signed URL to the ISO
4. Receive submissions — FoxCalc POSTs the ISO's configured terms to your callback URL
5. Subscribe to webhooks — Get notified about offer lifecycle events

Quick Start

# Create an offer
curl -X POST https://app.rbfoffercalc.com/api/v1/fox/offers \
  -H "Content-Type: application/json" \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "X-Timestamp: $(date +%s)" \
  -H "X-Signature: COMPUTED_HMAC_SIGNATURE" \
  -d '{
    "deal_id": "DEAL-001",
    "merchant_name": "Acme Corp",
    "iso_name": "Best ISO",
    "purchase_price_floor": 10000,
    "purchase_price_ceiling": 50000,
    "buy_rate": 1.20,
    "max_upsell": 0.10,
    "base_frequency": "daily",
    "available_frequencies": ["daily", "weekly"],
    "num_payments_floor": 60,
    "num_payments_ceiling": 252
  }'

Response:

{
  "id": "uuid",
  "deal_id": "DEAL-001",
  "version": 1,
  "status": "active",
  "calculator_url": "/DEAL-001?sig=abc123&exp=1700000000"
}

The full calculator URL is https://app.rbfoffercalc.com{calculator_url}.