Payment Gateway Optimizer

SKILL.md

---
name: Payment Gateway Optimizer
description: Compare payment processors on fees, conversion rates, and regional coverage to optimize checkout success rates.
---

# Payment Gateway Optimizer

Build a data-driven payment gateway comparison and routing strategy tailored to your ecommerce business model, transaction volume, target markets, and product category — covering fee optimization, conversion rate improvement, multi-gateway routing, and regional payment method support.

## Quick Reference

| Decision | Strong | Acceptable | Weak |
|---|---|---|---|
| Fee structure analysis | Breaks down interchange, assessment, processor markup, and currency conversion separately | Lists total effective rate per gateway | Uses advertised headline rates only |
| Conversion rate comparison | Analyzes authorization rates by card type, region, and transaction value bracket | Compares overall approval rates across gateways | Ignores conversion metrics entirely |
| Regional coverage | Maps local payment methods, local acquiring, and currency support per market | Lists supported countries per gateway | Assumes all gateways work equally everywhere |
| Multi-gateway routing | Defines rules for primary/fallback routing by card type, amount, and geography | Suggests a primary + one backup gateway | Recommends single gateway for everything |
| Integration complexity | Evaluates SDK maturity, documentation quality, sandbox environments, and migration path | Notes API type and basic integration timeline | Ignores implementation effort |
| Total cost modeling | Projects 12-month costs including hidden fees, FX markup, chargeback fees, and volume discounts | Estimates monthly cost at current volume | Compares only per-transaction rates |

## Solves

- Overpaying on transaction fees due to wrong gateway choice for your volume tier and business model
- Low checkout conversion caused by missing local payment methods in target markets
- High decline rates from using non-local acquiring in international markets
- Revenue leakage from unfavorable currency conversion markups
- Single-gateway dependency creating unnecessary downtime and concentration risk
- Inability to compare gateways apples-to-apples across all cost dimensions
- Missed volume discount thresholds from splitting transactions across too many processors

## Workflow

### Step 1 — Gather Business Parameters
Collect the core metrics that drive gateway selection:
- Monthly transaction volume (count and GMV)
- Average order value and value distribution
- Target markets (current and planned)
- Product type (physical, digital, subscription, marketplace)
- Current gateway and pain points
- Technical stack (Shopify, WooCommerce, custom, etc.)

### Step 2 — Map Payment Method Requirements
For each target market, identify required payment methods:
- Card networks (Visa, Mastercard, Amex, local schemes like Cartes Bancaires, iDEAL, Boleto)
- Digital wallets (Apple Pay, Google Pay, Shop Pay, regional wallets)
- Bank transfers and real-time payment rails
- Buy Now Pay Later options
- Local payment preferences and market share data

### Step 3 — Build Fee Comparison Matrix
For each candidate gateway, calculate the true cost:
- Base transaction fee (percentage + fixed)
- Interchange-plus vs. blended pricing analysis
- Currency conversion markup
- Cross-border fees
- Chargeback and dispute fees
- Monthly/annual platform fees
- PCI compliance fees
- Payout timing and fees

### Step 4 — Analyze Conversion Performance
Evaluate each gateway's impact on checkout completion:
- Authorization rates by card type and region
- 3D Secure implementation and smart exemptions
- Network tokenization support
- Retry and recovery capabilities
- Checkout UX impact (redirect vs. embedded)

### Step 5 — Design Multi-Gateway Routing Strategy
Create intelligent routing rules:
- Primary gateway assignment by transaction characteristics
- Fallback routing for declined transactions
- Cost-based routing for high-value transactions
- Geographic routing for local acquiring benefits
- A/B testing framework for ongoing optimization

### Step 6 — Model Total Cost of Ownership
Project costs across scenarios:
- 12-month cost projection at current volume
- Cost at 2x and 3x growth scenarios
- Volume discount threshold analysis
- Migration cost estimation (development, testing, certification)
- Opportunity cost of conversion rate differences

### Step 7 — Create Implementation Roadmap
Plan the migration or multi-gateway setup:
- Integration timeline and milestones
- Testing and certification requirements
- Rollout strategy (percentage-based, geographic, or product-based)
- Monitoring and alerting setup
- Performance benchmarking plan

## Examples

### Example 1: DTC Fashion Brand Expanding to Europe

**Context:** US-based DTC fashion brand doing $2M/month GMV on Shopify, currently using Stripe only. Expanding to UK, France, Germany, and Netherlands. AOV $85. Seeing 12% decline rate on European orders.

**Step 1 — Business Parameters:**
- 23,500 transactions/month, $2M GMV
- AOV: $85 (range $30–$400)
- Markets: US (80%), UK (8%), France (5%), Germany (4%), Netherlands (3%)
- Product: Physical goods, no subscriptions
- Current: Stripe (US), processing all international through US acquiring
- Stack: Shopify Plus

**Step 2 — Payment Method Requirements:**

| Market | Cards | Local Methods | Wallets |
|---|---|---|---|
| US | Visa, MC, Amex | — | Apple Pay, Shop Pay |
| UK | Visa, MC, Amex | — | Apple Pay, Google Pay |
| France | Visa, MC, CB | Cartes Bancaires (60% share) | Apple Pay |
| Germany | Visa, MC | SOFORT, Giropay | PayPal (50%+ share) |
| Netherlands | Visa, MC | iDEAL (70% share) | — |

**Step 3 — Fee Comparison (monthly at current volume):**

| Component | Stripe Only | Stripe + Adyen EU | Stripe + Mollie EU |
|---|---|---|---|
| US processing | $42,800 | $42,800 | $42,800 |
| EU processing | $11,200 | $7,840 | $7,200 |
| Cross-border fees | $4,800 | $960 | $880 |
| FX conversion | $3,200 | $1,600 | $1,440 |
| Platform fees | $0 | $250 | $0 |
| **Monthly total** | **$62,000** | **$53,450** | **$52,320** |
| **Annual savings** | — | **$102,600** | **$116,160** |

**Step 4 — Conversion Analysis:**
- Current EU authorization rate: 78% (vs. 94% domestic US)
- Projected with local acquiring: 91% EU authorization rate
- Revenue impact: +13 percentage points × $480K EU GMV = ~$62,400/month recovered revenue
- 3DS smart exemptions: additional 2-3% conversion lift on low-risk EU transactions

**Step 5 — Routing Strategy:**
- US transactions → Stripe (primary)
- UK transactions → Adyen UK entity (primary), Stripe (fallback)
- EU transactions → Mollie (primary for iDEAL, SOFORT, Cartes Bancaires), Adyen (card fallback)
- Transactions >$300 → Route to gateway with lowest interchange-plus rate
- Failed transactions → Automatic retry on alternate gateway with 30-second delay

**Step 6 — TCO Projection:**

| Scenario | Stripe Only | Multi-Gateway |
|---|---|---|
| Current ($2M/mo) | $744,000/yr | $631,680/yr |
| At $4M/mo | $1,488,000/yr | $1,198,080/yr |
| Migration cost | $0 | $45,000 one-time |
| Break-even | — | 5.7 months |

**Step 7 — Implementation Roadmap:**
- Weeks 1-2: Adyen/Mollie sandbox integration and testing
- Weeks 3-4: Payment method configuration and 3DS setup
- Week 5: Staged rollout — 10% EU traffic to new gateways
- Weeks 6-7: Increase to 50%, then 100% of EU traffic
- Week 8: Implement automatic failover routing
- Ongoing: Weekly conversion rate monitoring, monthly fee reconciliation

---

### Example 2: B2B SaaS with Subscription Billing

**Context:** B2B SaaS platform billing $500K/month across 800 subscriptions. Mix of monthly and annual plans. Currently on Braintree. High involuntary churn from failed renewals. Customers in US, Canada, UK, Australia.

**Step 1 — Business Parameters:**
- 800 active subscriptions, ~2,400 transactions/month (including retries)
- $500K monthly recurring revenue
- AOV: $625/transaction (range $49–$2,500/month)
- Markets: US (60%), Canada (15%), UK (15%), Australia (10%)
- Product: Digital SaaS, monthly and annual subscriptions
- Current: Braintree, 8.2% involuntary churn rate

**Step 2 — Payment Method Requirements:**

| Market | Primary Methods | Subscription Support |
|---|---|---|
| US/Canada | Visa, MC, Amex, ACH | Card-on-file, ACH recurring |
| UK | Visa, MC, Direct Debit | GoCardless/BACS Direct Debit |
| Australia | Visa, MC, BECS | BECS Direct Debit |

**Step 3 — Fee Comparison:**

| Component | Braintree | Stripe Billing | Stripe + GoCardless |
|---|---|---|---|
| Card processing | $16,250 | $17,250 | $13,800 |
| ACH/Direct Debit | $480 | $640 | $320 |
| Subscription mgmt | $0 | $0 | $150 |
| Failed payment retries | $1,200 | $800 | $600 |
| **Monthly total** | **$17,930** | **$18,690** | **$14,870** |

**Step 4 — Conversion Analysis:**
- Current renewal success rate: 91.8%
- Stripe smart retries: projected 95.5% renewal rate
- Adding Direct Debit for UK/AU: projected 97.1% for those regions
- Revenue impact of reducing involuntary churn from 8.2% to 4.5%: $18,500/month saved

**Step 5 — Routing Strategy:**
- US/Canada card subscriptions → Stripe Billing with smart retries
- US high-value (>$500/mo) → Offer ACH with discount incentive ($5/mo off)
- UK subscriptions → GoCardless BACS Direct Debit (primary), Stripe card (fallback)
- Australia subscriptions → Stripe with BECS Direct Debit where available
- Failed card renewals → Dunning sequence: retry day 1, 3, 5, 7 with card updater

**Step 6 — TCO Projection:**

| Metric | Current (Braintree) | Optimized (Multi-Gateway) |
|---|---|---|
| Processing costs | $215,160/yr | $178,440/yr |
| Revenue lost to churn | $492,000/yr | $270,000/yr |
| **Effective annual cost** | **$707,160** | **$448,440** |
| Migration cost | — | $30,000 one-time |

**Step 7 — Implementation:**
- Weeks 1-3: Stripe Billing migration (sandbox testing, subscription import)
- Weeks 4-5: GoCardless integration for UK Direct Debit
- Week 6: Card updater and smart retry configuration
- Weeks 7-8: Dunning email sequence setup and testing
- Week 9: Staged migration — new subscriptions first
- Weeks 10-12: Migrate existing subscriptions in batches
- Ongoing: Weekly churn monitoring, monthly gateway performance review

## Common Mistakes

1. **Comparing headline rates only** — Advertised rates exclude interchange markup, cross-border fees, FX conversion, and platform fees. Always calculate the effective total rate for your specific transaction profile.

2. **Ignoring authorization rates** — A gateway that is 0.3% cheaper but has 5% lower authorization rates costs far more in lost revenue. Always factor conversion into total cost analysis.

3. **Overlooking local payment methods** — In many European and Asian markets, local methods account for 50-70% of transactions. Failing to support them means losing the majority of potential customers.

4. **Using single-gateway architecture** — Single points of failure in payment processing directly impact revenue. Even a 99.9% uptime SLA means 8.7 hours of downtime per year.

5. **Not negotiating volume discounts** — Most gateways offer custom pricing above $50K/month. The difference between standard and negotiated rates can be 0.3-0.5% on every transaction.

6. **Choosing based on developer experience alone** — A beautiful API doesn't compensate for poor authorization rates or missing payment methods in your target markets.

7. **Ignoring payout timing** — The difference between T+2 and T+7 payout cycles significantly impacts cash flow, especially for high-volume businesses. Factor working capital cost into comparisons.

8. **Treating 3D Secure as binary** — Modern gateways offer smart 3DS with exemptions for low-risk transactions. A gateway that blanket-applies 3DS to everything will tank your conversion rate.

## Resources

- [Output Template](references/output-template.md) — Structured gateway comparison and routing strategy deliverable
- [Fee Calculation Reference](references/fee-calculation-reference.md) — Detailed fee structures and calculation methods for major gateways
- [Regional Payment Methods Guide](references/regional-payment-methods.md) — Payment method coverage and market share by region
- [Quality Checklist](assets/quality-checklist.md) — Comprehensive review checklist for gateway optimization deliverables