Every brand we talk to wants the same thing at checkout: more confidence, less hesitation. Shoppers with multiple credit cards face a quiet moment of friction — "which card should I use?" — that costs you conversions. That hesitation has nothing to do with price. It's about uncertainty.
Today we're launching the SuperPay Merchant API — a free Checkout API and drop-in widget that surfaces the top 3 cards by reward rate for this purchase, right at the moment of decision. One row per card, ranked best first, each tappable to apply.
Why three, not one?
Different shoppers carry different wallets. Showing only "the" best card means most shoppers see a card they don't have. Showing the top 3 dramatically increases the odds the shopper recognizes one in their wallet — and the runner-ups double as discovery for cards worth applying for. The widget ranks by effective reward rate (descending), uses popularity as a tie-breaker, and prefers the lower-annual-fee card on the next tie.
Why Reward Visibility Matters
Shoppers carry an average of 3–4 credit cards. Each one has different reward rates for different categories. At checkout, that complexity becomes friction.
- A shopper who doesn't know which card to use hesitates, second-guesses, and sometimes abandons the cart entirely.
- A shopper who sees "Use your Chase Sapphire — earn $12.90 back" feels smart, buys with confidence, and comes back.
The SuperPay widget turns that moment of uncertainty into a moment of delight. Same purchase, same price — but the shopper feels like your checkout is working for them.
Show the Effective Cost, Right Under "Place Order"
Confidence climbs another notch when the shopper sees what the order actually costs after the rewards their top card will earn. Add one optional attribute (data-superpay-effective-cost-target) and an empty target div under your pay button, and the widget renders a single muted line: "Effective cost with SuperPay: $82.21 — after $5.24 rewards." It's strictly gated — cashback top pick only, positive reward only, known cart amount only, and the effective cost must stay non-negative (rewards are never shown as exceeding the order total) — so the number can never mislead. Points and miles top picks, $0 estimates, and missing totals all suppress the line silently.
How It Works in 30 Seconds
Two lines of code. That's the integration.
- Add the script tag to your checkout page — one line of HTML.
- Add the widget div where you want the card recommendation to appear.
SuperPay never touches your payment flow. Stripe, Shopify Payments, Adyen — whatever you already use — keeps processing the transaction. We just show the shopper their top 3 cards.
Who It's For
The Merchant API is built for any online merchant who wants a smarter checkout:
- E-commerce brands looking to reduce cart abandonment and lift average order value
- Considered-purchase categories (electronics, travel, home goods) where checkout confidence matters most
- Any merchant who wants to give shoppers a reason to feel great about completing the purchase
Distribution, Built In
Once you're live on the Merchant API, your brand becomes discoverable inside the SuperPay consumer app — surfaced to shoppers who are already optimizing their card spend. We're not just a checkout widget. We're a discovery channel that brings high-intent shoppers to your store.
Pricing
- $0 to install. One script tag, one div.
- $0 monthly. No fees, no per-call charges, no usage caps.
- No contract. No rev share. Cancel any time.
Get Started
Visit /for-merchants to provision a sandbox key in under a minute, or read the full Merchant Partner Guide (also downloadable as a PDF) for the complete walkthrough — code samples, security model, FAQs, and a launch checklist.
Questions about the API or want to discuss a custom integration? Email us directly at hello@superpayrewards.com. Same business day reply, every time.
SuperPay sits in the decision layer between the cart and the card. The Merchant API is how your brand gets there.