PM Payment study

Decision brief · 11 August 2026

Payment stack for an AI art credit product

Sell prepaid generation credits from Hong Kong or Singapore, accept global customers, and keep the first integration simple enough to operate safely.

See the recommendation Scope & method
source.jpgredesign / 04

PACK PURCHASE

60 credits
Paymentverified
Ledger+60
01 / Recommendation

Default choice

Start with Stripe Checkout.

It gives a new product the best balance of launch speed, global cards and wallets, strong developer tooling, and control over the credit ledger. Stripe is available to businesses in both Hong Kong and Singapore and supports charging in 135+ currencies.1, 2

Choose Airwallex instead when Hong Kong local conversion is central and FPS, Alipay, or WeChat Pay matter from day one. Choose Paddle instead when removing most global sales-tax administration is worth a higher transaction fee and less checkout control.

A
Fastest sensible launch

Stripe hosted Checkout + your own credit ledger

B
Asia-local payments

Airwallex + local methods + multi-currency wallet

C
Tax simplicity first

Paddle as merchant of record, subject to approval

02 / Pack economics

See the fixed-fee effect

Published standard domestic-card rates. This estimate excludes FX, tax, disputes, refunds, and negotiated pricing.

Business location
Rule of thumb

Use larger packs so the fixed transaction fee consumes less of each sale. Never set pack prices from competitors alone; start from generation cost, failure rate, support, tax, and target gross margin.

Estimated monthly processing

Airwallex3.30% + HK$2.35
HK$2,7935.70% effective
Stripe3.40% + HK$2.35
HK$2,8425.80% effective
Difference at this volumeHK$49 / monthPrice is only one criterion. Tax tooling, local methods, support, and implementation risk can outweigh this difference.

03 / Provider comparison

Six credible routes

Processor means your company remains seller of record. MoR means the provider resells the digital service and takes on substantial payment and indirect-tax responsibility.

ProviderModelPublished starting priceBest atTrade-offVerdict
StripeHK + SG
ProcessorHK: 3.4% + HK$2.35
SG: 3.4% + S$0.502		Fast integration, global cards, wallets, billing and tax add-onsYou own tax registrations, filings, disputes and credit liabilityBest default
AirwallexHK + SG
ProcessorHK: 3.30% + HK$2.35
SG: 3.30% + S$0.50; +0.3% international cards3, 4		Asian local methods, multi-currency collection and FXBroader finance platform; validate API/support fit for your teamStrong Asia option
PaddleGlobal digital
Merchant of record5% + US$0.50 per Checkout transaction5Tax registration, collection, filing and remittance bundledHigher fee, provider product approval, less payment controlBest for tax relief
Lemon SqueezyGlobal digital
Merchant of record5% + US$0.50; +1.5% international, +1.5% PayPal, +0.5% subscription6Simple digital-product setup; HK and SG bank payouts listedOutside-US card sales commonly reach 6.5% + US$0.50Easy, expensive
PayPalGlobal wallet
Processor / walletHK standard domestic commercial: 3.9% + fixed fee; cross-border additions vary7Buyer familiarity and a useful secondary walletComplex regional fee tables; weaker primary developer experienceAdd later
AdyenEnterprise global
ProcessorUS display: US$0.13 + payment-method fee; cards use Interchange++; minimum invoice may apply8Large scale, many markets, unified enterprise paymentsSales-led and usually excessive for an early-stage appRevisit at scale

Prices are not fully apples-to-apples. International cards, currency conversion, refunds, disputes, tax products, subscriptions, and negotiated rates can change the total.

04 / Market notes

Where the details change

HK

Hong Kong base

Lead with cards, Apple Pay, Google Pay, Alipay, and WeChat Pay. Airwallex explicitly lists FPS among its local methods. Hong Kong has no broad VAT or GST, but profits tax, business registration, and customer-country digital tax can still apply.

Evidence: Airwallex pricing, Hong Kong tax overview

SG

Singapore base

Enable cards, wallets, and PayNow where your provider supports it. Singapore GST is 9%; registration rules depend on turnover and where the supplier is established. Overseas digital suppliers have a two-threshold registration test.

Evidence: Stripe SG pricing, IRAS remote services

GL

Global customers

Show local currency where practical, but avoid unnecessary FX settlement. EU, UK, Australia, Canada, and other markets can tax B2C digital services at the customer location. A processor gives control; an MoR buys operational relief.

Operational conclusion from tax and provider sources below.

05 / Implementation blueprint

Payment is an event.
Credits are a ledger.

Do not update a balance because the browser reached a “success” page. Only a verified server-side webhook can create credits.

  1. 01
    Create order

    Your server records pack ID, exact price, currency, user ID, and an idempotency key.

  2. 02
    Hosted checkout

    Redirect to Stripe Checkout or the chosen provider. Never collect raw card data yourself.

  3. 03
    Verify webhook

    Check the signature and provider event ID. Ignore duplicates and mismatched amounts or currencies.

  4. 04
    Write ledger entry

    Append a purchase grant. Keep an immutable history instead of only mutating one balance field.

  5. 05
    Consume atomically

    Reserve credits before generation; finalize on success and release or compensate on failure.

  6. 06
    Reverse safely

    Refunds and disputes create negative ledger entries, an account hold, or a manual review.

Credit terms

Make credits closed-loop

State that credits are non-transferable, have no cash value, and are redeemable only for your generation service. Publish expiry and refund rules clearly. Ask the provider to approve the model before launch.

Content risk

Protect the payment account

Require users to confirm rights to uploaded images. Enforce prohibited-content rules, preserve moderation evidence, rate-limit abuse, and define what happens when a generation is rejected.

06 / Offer design

A credit model that stays legible

Keep the first catalog small. These tiers are a structure, not price advice; calculate the numbers from your actual inference cost.

TRY

Starter

20 credits

Low commitment, but still large enough that fixed payment fees do not dominate.

CORE

Studio

60 credits

Your anchor pack. Offer a modest unit-price improvement, not a confusing bonus formula.

VOLUME

Pro

150 credits

Best unit economics. Add spend controls and invoices if small teams become a real segment.

Minimum pack price(generation cost + support + expected failures + payment fixed fee) ÷ (1 − payment % − tax − target margin)

07 / Launch order

Ship in four passes

  1. 1

    Confirm entity and underwritingApply with the actual website, refund policy, content policy, pricing, sample outputs, and clear credit terms.

  2. 2

    Launch one processorStripe Checkout, cards and wallets first. Add SG PayNow or HK-focused local methods only when customer data supports it.

  3. 3

    Instrument the funnelTrack checkout opened, payment completed, payment failed, refund, dispute, and credits consumed by country and method.

  4. 4

    Re-evaluate at evidence pointsConsider Airwallex for Asia conversion, Paddle for tax workload, or Adyen only after volume and market spread justify migration cost.

Method

Scope and confidence

This study assumes a Hong Kong or Singapore company selling its own non-transferable prepaid credits for web-based AI image generation. It excludes marketplace payouts, crypto, native mobile-app billing, and cash-equivalent stored value. Native iOS or Android apps require a separate review of Apple and Google in-app-purchase rules.

Provider pricing and availability are time-sensitive. Published list prices were checked on 11 August 2026. Product acceptance, reserves, payout timing, dispute pricing, and negotiated rates require a written quote or approved account. Tax notes are orientation, not legal or tax advice.

Evidence ledger

Primary sources

Official sources were preferred. All accessed 11 August 2026.

  1. 01
    Stripe global availability

    Lists Hong Kong and Singapore; primary source. High confidence.

  2. 02
    Stripe Hong Kong pricing · Singapore pricing

    Standard card rates, PayNow note, refund treatment, no setup/monthly fee; primary. High confidence.

  3. 03
    Airwallex Hong Kong pricing

    Card rates and listed local methods including FPS, Alipay, and WeChat Pay; primary. High confidence.

  4. 04
    Airwallex Singapore pricing

    Domestic and international card list rates and local-method claim; primary. High confidence.

  5. 05
    Paddle pricing

    5% + US$0.50 Checkout price and bundled tax/compliance positioning; primary. High confidence for list price.

  6. 06
    Lemon Squeezy pricing · fee details · payout countries

    Base and surcharge schedule; HK and SG bank payouts; primary. High confidence.

  7. 07
    PayPal Hong Kong merchant fees

    Domestic commercial and additional cross-border fee structure; primary. Medium-high confidence because several product-specific rates coexist.

  8. 08
    Adyen pricing

    Processing-fee-plus-method-fee model, Interchange++, no setup/monthly fee, minimum-invoice caveat; primary. High confidence.

  9. 09
    IRAS: GST and the digital economy

    Singapore GST framework for digital-economy supplies, with links to the current remote-service guidance; government primary source. High confidence.

  10. 10
    Hong Kong Inland Revenue: tax index

    Official overview of Hong Kong's tax system. Use a local adviser for the product-specific treatment; government primary source. High confidence for general framework.

  11. 11
    Stripe Tax pricing

    Tax Basic/Complete scope and published 0.5% calculation rate where registered to collect; primary. High confidence.

  12. 12
    Stripe supported currencies

    135+ presentment currencies and settlement caveats; primary. High confidence.