How to Let B2B Customers Pay Invoices Online (Self-Service AR Portal) in 2026
To let B2B customers pay invoices online, give them a self-serve portal where every invoice, balance, and document lives in one place and they can pay by ACH, wire, check, or credit card without emailing anyone for a copy. A good portal removes the friction that delays payment, the lost invoice, the missing remittance details, the pending W-9, so customers pay the moment they are ready. That pulls days out of your cycle and takes the back-and-forth off your team.
Why should you let customers pay invoices online?
The reason is usually access rather than willingness. When a customer wants to pay but cannot find the invoice, does not have your bank details, or is waiting on a document, the payment stalls in someone's inbox until it gets sorted out by hand. Each of those handoffs is a delay you can design out. Put everything a customer needs to pay in one place and the delay disappears, and a tidy self-serve process signals that you are organized, which tends to move your invoices up the queue.
What does a good customer payment portal include?
The test is whether a customer can answer every question and complete payment without contacting you. That means:
- Every invoice with its current status, including payments already in transit.
- A clear balance view: open, current, and overdue, with invoice aging.
- Payment by more than one method, so the customer uses whatever their process requires.
- Payment history, so nobody has to ask what has been paid.
- Statements and credit memos, available on demand.
- Documents like your W-9, ready to download rather than requested by email.
- Autopay, so recurring invoices clear without a manual step each time.
How do customers pay online?
Give them a few rails and let them choose. Most B2B portals support ACH for the low-cost default, wire for large or international payments, check for customers who still work that way, and credit card for those who prefer to pay by card. The detail that matters is that paying should take a few clicks from the invoice itself rather than a separate login to a bank portal with your account number copied from an email. Autopay goes one step further: a customer enrolls once and future invoices are paid automatically.
Portal vs emailing invoices
The difference shows up in how many touches it takes to get paid.
| Emailing invoices | Self-service portal | |
|---|---|---|
| Finding the invoice | Customer emails to ask for a copy | Always available in the portal |
| Remittance and W-9 | Sent on request, often delayed | Downloadable any time |
| Paying | Off-platform, manual | A few clicks from the invoice |
| Status and history | Nobody is sure what is paid | Visible to both sides |
| Your team's effort | Repeated back-and-forth | Customers self-serve |
How do you roll out a customer payment portal?
Keep it simple so adoption is easy. Connect the portal to your invoicing so balances and statuses stay live, turn on the payment methods your customers use, and make sure documents like your W-9 are loaded so they are never a reason to stall. Then point customers to the portal in your invoices and reminders, and offer autopay to the accounts that pay you regularly. The goal is that a customer never has to email you to pay.
How does Monk do this?
Monk's Payment Hub is a branded self-serve portal for each customer. They see every invoice and its status, their balances and aging, payment history, statements, credit memos, and documents like your W-9, and they pay by ACH, wire, check, or credit card, or enroll in autopay. Because it runs on the same platform as collections and cash application, a payment made in the portal applies to the invoice and stops the follow-up automatically. More than $2B in receivables runs on Monk today. See the Payment Hub launch, and for the broader case, what a customer portal is and why it matters for AR.
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