The Payment Gateway Buying Guide

The 8-week procurement timeline

Week 1: Requirements

• GMV, average ticket, transaction count, refund rate, dispute rate.
• Channel mix: online vs in-person vs invoice.
• Card mix: domestic vs international, consumer vs commercial.
• Volume seasonality (Q4 ecommerce spike, summer travel).
• Hard requirements: split payments, multi-currency, 3DS, hosted UI, recurring.

Week 2: Shortlist

• Run the cross-vendor calculator with your real numbers.
• Include 1 published-rate flat (Stripe or Square), 1 published-rate IC+ (Helcim or Stax), 1 quote-only enterprise (Adyen or Worldpay) if your volume justifies.
• Do not put 8 vendors on the shortlist. The marginal vendor adds engineering time without changing the answer.

Week 3-4: RFP

Use the 27-question RFP template. Demand line-item pricing, not just headline rates.

Week 5: Technical bake-off

• Sandbox account on each shortlisted vendor.
• Run 5 reference flows: payment, refund, dispute, recurring renewal, webhook reliability.
• Time-to-first-tokenisation and developer-experience scoring (1-5 per criterion).
• Authorisation-rate test on 100 reference cards if your acquirer-rate matters.

Week 6: Pricing negotiation

• Above $80K/mo, ask for an interchange-plus offer regardless of which model you came in on.
• Push back on monthly minimums, PCI fees, statement fees, batch fees.
• Ask for FX margin reduction explicitly (Stripe will move on 1% above $5M/yr exposure).
• Negotiate the contract term: 12-month tends to beat multi-year on flexibility, but 24-36 month commitments win on rate.

Week 7-8: Legal review and onboarding

• Check the early-termination clause carefully. Some processors impose 12+ months of estimated fees if you leave.
• Check the reserve clause. Standard for high-risk, surprising for standard merchants.
• Onboarding takes 1-2 weeks for KYB / underwriting before you can take live transactions.

Related

• RFP template
• Implementation cost
• Quote-only vendor handling