Guides
Payments guides for software platforms
Plain-English guides to how ACH bank payments and card payments work and the rules your platform follows, reviewed October 2026.
Bank payments
ACH payment guides
ACH payments move money between US bank accounts over the ACH Network. If your platform is adding bank payments, start with these ACH guides: how a payment moves, what authorization you need, what happens when a payment comes back, and whether Nacha’s fraud monitoring rules reach you.
How ACH payments work, including Same Day ACH
The parties in an ACH payment, how credits differ from debits, how entries settle between banks, and the Same Day ACH processing windows and limits.
ACH authorization requirements
What to collect before you debit a customer’s bank account, how authorization differs by SEC code, and where account validation, micro-entries and prenotes fit.
ACH return codes
What the common return codes mean, the windows for sending returns, the return-rate limits Nacha monitors, and what to do after each kind of return.
Nacha fraud monitoring rules
Who Nacha’s fraud monitoring rules cover, whether they reach a platform that sends ACH payments for its customers, and the dates that matter.
Costs and disputes
Fees, disputes and cards
These guides cover what card and ACH payments cost, how a card chargeback differs from an ACH return, and which company does what when a card payment moves. Read them before you decide how to price payments for your customers or how your team will handle disputes.
Credit card processing fees explained
Interchange, network fees and markup, how common pricing models differ, and where surcharging rules stand as of October 2026.
ACH processing fees explained
What an ACH payment costs, what returns and the Same Day Entry Fee add, and how ACH costs compare with card processing fees.
Chargebacks vs ACH returns
Who starts a chargeback and who starts an ACH return, the time limits on each, whether you can respond, and the monitoring thresholds that apply.
Payment gateway vs payment processor
What a payment gateway does, how it differs from a processor, and where acquirers, card networks and issuers fit as a card payment moves to settlement.
Product decisions
Choosing methods and models
Three decisions shape how payments fit into your software: which methods to offer your customers, how PCI DSS applies to what you build, and which payments model suits your business.
ACH vs credit card
How cost, speed, certainty and dispute risk compare, and which payments in your software suit a card and which suit a bank payment.
PCI compliance for SaaS platforms
What PCI DSS asks of a platform and of the merchants who use it, and how the way you build payments changes your PCI scope.
PayFac vs ISO
How payment facilitators, ISOs and PayFac-as-a-Service differ on risk, settlement and network rules, and what each model asks of your platform.
How to use these ACH and card payment guides
Each of these payment processing guides is based on primary sources where available, shows its last-reviewed date (October 9, 2026) and a Sources list, and labels any figure taken from a secondary source. Read how we write our guides.
Payment rules change, so confirm the details with your provider or the rule source before you act on them. The guides explain how payments and their rules work; they are not legal advice.
Looking for a single term? The payments glossary defines card, ACH and platform terms in plain English. For short answers, see common questions about card and ACH payments.
Talk to BrainMerchant
Turn what you have read into a payments plan
BrainMerchant processes credit card and ACH payments for software platforms. Tell us which of these topics matter most to your platform, and we’ll walk you through what adding card and ACH processing with BrainMerchant looks like.