The Invoice Becomes the Shopping Cart in B2B Payments

Here’s proof. Take a look at where small and mid-sized businesses actually buy now. Analysts project Amazon Business to capture more than $80 billion in volume. A 2025 Capitol One study found that more than half (57%) of U.S. B2B buyers purchase through it and 39% purchase through Walmart Business.  Costco is growing its digital channel at double digits, quarter after quarter.

That’s not consumer behavior leaking into work. That’s the de facto head of SMB procurement filling her shopping cart with the products she needs to run the business. The breakroom supplies, the office gear, the everyday consumables, the long tail that never justified a purchase order. A growing portion now runs through a cart with a business account and a card on file.

The person who’s holding that card is the small and mid-sized business owner, already checking out on a virtual or commercial card, already living in the eCommerce/shopping cart world without calling it that. They just experience it as “buying on Amazon” rather than as the death of the invoice.

Read More: Big Tech Is Rewriting Procurement. The Rest of B2B Is Next

But that’s only the tail spend. The more telling move is happening in the strategic and planned spend, the materials that are the business.

A steel fabricator used to buy steel by calling five service centers and waiting for quotes. Now there’s Bryzos, where you type what you need, see real-time pricing, and place the order in under a minute. A manufacturer used to source chemicals through a sales rep and a negotiated contract. Now there’s ChemDirect, hundreds of thousands of products, near-perfect order rates, payment terms built in. These exchanges and others took the most negotiated, most relationship-bound, most invoice-heavy transactions in the industrial economy and turned them, more or less, into a cart.

The bigger suppliers build the cart into the buyer’s own procurement system. This is PunchOut, and it’s the unsung hero of B2B ecommerce. The supplier exposes a catalog. The buyer’s purchasers, sitting inside their own procurement platform, punch out to that catalog, see the products and the contract pricing negotiated for their account, fill a cart, and send it back into their approval flow. They only ever see what they’re authorized to buy, at the price already agreed. That’s the death of the invoice in real life. Instead of the supplier sending a bill, the buyer’s purchasing system handles the transaction. The catalog became the front door. The invoice never made it in.

Read More: B2B Selling Platforms Come of Age With Embedded Payments

And here’s the tell. Every one of these exchanges solved payments first, not last. Bryzos funds the seller automatically so nobody chases collections. ChemDirect lets the buyer pick terms and the supplier still gets paid. The exchange didn’t bolt a payment onto a marketplace. It built the marketplace around the payment. In a fragmented, nervous, trust-poor market, you can’t separate “find the supplier” from “pay the supplier safely.” The exchanges figured that out first because they had no choice.

So the cart didn’t stay in retail. The bill became a basket. The invoice is becoming the shopping cart. Procurement is becoming a line of code that runs inside the buying flow. And the two are meeting in the middle, at the cart, in a single click. Whoever owns that click owns the relationship, the data and the flow of funds. Everyone else becomes a feature. And features get commoditized over time.

Invoices Were Always a Contested Control Point

The invoice has always held an important job to be done in commerce. It’s the trigger. The seller decides when the bill goes out, what terms it states, what payment options it will accept. But the trigger was only ever half the control. The other half belonged to the buyer, who decided what actually happened next. Whether to pay on day five or day 95, whether to honor the stated terms or stretch them, which method to use, whether to route over the rail the seller wanted or just cut a check. The seller may have fired the starting gun. The buyer ran the race at whatever pace suited their cash position.

That split is one of the reasons that the invoice is losing its mojo. Control over the moment money moves was divided between the party who issued the bill and the party who paid it, and the gap between them is where the friction lives. The delay, the check-instead-of-ACH or instant payments, the net-30-that-becomes-net-75. In the invoice-intensive industries, most of the money never moved over the seller’s preferred rail at all. The control point was contested, and the buyer usually won the part that mattered.

Six invoice-intensive industries do a lot of this. Construction, manufacturing, transportation, professional services, administrative and support services, and wholesale trade run on the invoice the way retail runs on the register. Roughly seven trillion dollars in addressable sales moves annually in the U.S. through bills sent to buyers. The invoice isn’t a document in these industries. It’s the foundation.

When the bill becomes a shopping basket, the trigger and the payment happen simultaneously. The buyer doesn’t receive a bill and decide later how and when to pay. They pay at the moment of order, on the terms embedded in the cart. For the first time, the moment money moves has a single owner. The supplier. That’s what “own the click” actually means. Not a better invoice, but the end of the split that made the invoice weak.

Four Ways the Invoice Gets Eaten

Five hundred and sixty billion invoices aren’t going to disappear all at once. Not even close. But invoices will get disrupted, just like every other facet of payments and commerce. We can watch the disruption happen in four different ways. And all four are already happening.

The first is commoditization. Point-of-sale and accounts-payable platforms add invoicing to their offer. The invoice stops being a specialized document and becomes a generic feature inside a bigger platform, one checkbox among many. Whoever owns the platform now owns the invoice as a side effect.

The second is embedding. Contract and e-signature tools bake the bill into the agreement. You sign, billing starts, and the invoice step goes away.  There was never a separate document. The money was wired into the contract.

The third is replacement. Service and business aggregators productize the invoice into a shopping cart module. The buyer doesn’t receive a bill and pay it. The buyer checks out. Same money, different mechanic, and the mechanic is a cart.

The fourth is specialization. Vertical software builds industry-specific billing that displaces the generalist invoice. Field-service software for the trades, shop software for auto repair, commerce networks for fashion and beauty. Each one solves a vertical’s billing better than a generic invoice ever could, and each one captures the payment in the process.

Regardless, all four mechanisms end in the same place. The standalone invoice becomes a feature inside someone else’s platform. The control point now sits with whoever owns the cart and the payment underneath it.

Procurement Is Just One More Thing That Gets Embedded

The exact same thing is happening to procurement, on the buyer’s side of the deal, at the exact same time.

Procurement used to be a place. In a big company it was a department, a team, a set of approvals you walked through before you were allowed to spend. In a small business it was the owner with a card and a shoebox of receipts. Either way, procurement was a gate. It sat between the buyer and the purchase.

Especially now with AI and agents, the gate is dissolving into code.

In the enterprise, the source-to-pay platforms turned procurement into embedded workflow. The approval, the card, the payment, the reconciliation now fire automatically inside the buying flow. The PunchOut catalog already enforces who can buy what, from which supplier, at which price. The virtual card appears when the workflow triggers it, with the exact limit, ready to use, and it disappears once the transaction clears. Nobody walks through a gate. A rule makes it so. Procurement got absorbed into the cart.

For the small and mid-sized business, the gate was never a department, so the embedding comes from the other direction. Their suppliers’ invoices are becoming carts they check out of. Their own buying moves onto Amazon Business and the vertical exchanges, where the procurement logic, the catalog, the terms, the approval, the payment, the reconciliation, lives inside the platform instead of inside a person. The owner stops doing procurement. The platform does it invisibly, in the background.

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The invoice is being embedded on the sell-side. Procurement is being embedded on the buy-side. And they meet in the middle, at the cart, in a click. A productized invoice coming from the seller and an embedded procurement decision coming from the buyer turn out to be the same event. The bill the seller used to send and the approval the buyer used to grant collapse into a single checkout.

That’s the move. Top-of-wallet became top-of-agent. Now top-of-cart becomes top-of-the-entire-money-movement-relationship.

The Virtual Card Is the Thing That Carries the Money Through

None of this works without something to carry the money through the embedded moment. That something is increasingly the virtual card. And this is where our own data gets specific, because we’ve been measuring it for three years.

Start with the problem the card solves. PYMNTS Intelligence found in the September 2025 Accounts Payable Tracker that more than two-thirds of businesses (68%) still key invoices by hand. Think about that. In an economy this digital, the back office is still typing bills into a system one line at a time. That’s the friction the card removes. Fully managed payment services let firms process invoices up to four times faster, cut late-payment penalties and get real-time visibility into cash flow.

Now the working capital piece, because this is the heartbeat of it. The Growth Corporates Working Capital Index, the third annual PYMNTS Intelligence study with Visa Commercial Solutions, has collectively surveyed more than 3700 CFOs and treasurers across 23 countries and 10 industry verticals in those three years. In 2026, we found that working capital efficiency unlocked an average of $19 million in savings for middle-market firms last year. Not from borrowing more. From moving money smarter. The most efficient performers paid a meaningful share of their invoices ahead of schedule, which sounds backwards until you see the logic. Early payment locks in pricing, secures inventory during shortages and buys leverage with suppliers when competitors are slower to move. The virtual card is what makes paying early cheap and fast enough to be worth it.

Read More: The Growth Corporates Working Capital Index 

We also found that CFOs now reach for working capital to fund unplanned growth rather than to plug an emergency, and a majority use corporate and virtual cards specifically to reduce days sales outstanding and accelerate cash flow. The card isn’t a payment method anymore. It’s a working capital instrument. It’s an advantage no other rail carries built in. An ACH push moves money. A check moves money slowly and sees increasing incidences of fraud. A virtual card moves money and extends payables and feeds the data, all in one motion.

With AI and intelligent agents sitting in the buying flow, the payment method becomes a decision, not a default. The agent optimizes at the transaction level, weighing fees, terms, supplier behavior, rebate tiers and cash position to pick the right rail and the right timing for this purchase. Card here for the working-capital advantage and the rebate. ACH there because the supplier won’t take the card. Early payment on the invoice where the discount beats the cost of capital. That’s a level of optimization no AP clerk works out by hand. The card plus the model is what turns the back office into a profit center, and the virtual card wins more of those decisions precisely because working capital is baked into it.

The mid-market is where the gap is widest, and the opportunity with it. The same index found loan rejection rates climbing sharply from 4% to 27% as banks lag on digital-first, tailored offerings. Traditional underwriting doesn’t fit the cash flow reality of a small or mid-sized firm. As JOOR’s CFO put it to me, it isn’t about creditworthiness, it’s that these businesses don’t fit the models banks built for someone else. So alternative lenders and embedded finance step into the void. That’s the structural reason virtual cards and embedded credit are growing fastest exactly where the banks are weakest.

The small business buyer is already in the cart, on a card. Our study with Mastercard found nearly half of small businesses are highly interested in cutting their reliance on cash, even as cash and checks still run many of the workflows they live in. Larger SMBs, retail firms and urban businesses already treat the card as a central operating tool. Smaller and rural firms face more friction and need more support. That unevenness is the map of where the volume is still sitting, waiting.

Read More: Supplier Enablement Programs Accelerate Virtual Card Use

The runway is enormous, because adoption is still early. Our work with WEX found nearly nine in ten firms adopting or pursuing virtual cards, while real penetration sits at a small fraction of eligible spend. The intent is nearly universal. The execution has barely started.

That gap is the whole opportunity.

Suppliers Lead. Agents Accelerate.

So who wins, and why is this finally the moment it happens?

Here’s the reality. For all the talk of cards eating B2B, commercial cards are still less than 3% of global B2B payments. U.S. virtual card volume reached an estimated $662 billion in 2025, growing 25% in a year, against something like $17.6 trillion still moving over ACH. The card hasn’t won. It’s barely begun.

For thirty years the answer was supposed to be persuasion aimed at the buyer. Digitize the back office. Sell the CFO on cards and the rebate. Talk procurement into changing how it pays. It never fully worked because the buyer had no good reason to move and suppliers had no incentive to accept an expensive card payment.  The invoice and the payments workflow that it triggered was good enough for the person receiving it.

Today, and in an agentic world, the shift isn’t coming from the buyer. It’s coming from the supplier.

Suppliers are the ones with the urgent reason to change, because the supplier who is easy to find, easy to buy from and easy to pay wins the business, and the supplier who makes you call for a quote and wait for an invoice loses it.

Put your catalog online and a buyer finds you at a search box instead of through a salesperson. Expose real-time pricing and the buyer orders in a minute instead of a week. Build payment into the checkout and you get funded on the spot instead of chasing a check for sixty days.

Discoverability, self-service and pay-enablement aren’t conveniences. They’re how a supplier captures demand that used to take five phone calls to shop. Getting found and getting paid were never separate moves. They were the same move, and the supplier who made it captured the buyer.

So suppliers keep migrating to where the demand is, and the demand keeps moving to the cart. Grainger has spent years rebuilding its business around eCommerce because that’s where its buyers now start. The vertical exchanges productize the most negotiated transactions in the industrial economy because a carted, pay-enabled storefront wins the order. The big distributors PunchOut straight into the buyer’s system because being inside the buyer’s procurement flow beats sitting in an inbox waiting to be opened. None of this was forced on anyone. Suppliers did it because it works.

Agentic commerce is what will turn that migration into a stampede. When buyers start delegating purchases to agents, being carted and API-native stops being an advantage and becomes the price of being transactable at all.

An agent buys from the supplier whose catalog it can read, whose price it can see, whose checkout it can complete and whose credential it can settle, instantly, inside the flow. The supplier who is still sending PDFs and waiting on checks or an ACH payment doesn’t lose the deal on the merits. It never enters the consideration set, because the agent can’t see it, can’t read it and can’t pay it.

And agents don’t shop at human pace. They source, reorder and settle continuously, across thousands of line items, faster than any sales desk could return a quote. The supplier built for that speed gets bought on repeat. The one that isn’t gets stranded.

That is what finally what could unlock the spend sitting at less than 3%. Not a better pitch to CFOs, but suppliers racing to be findable, buyable and payable in one motion, and agents rewarding the ones who got there. The credential that wins inside that flow is the smart one, the rail an agent can optimize, that carries working capital, settles with a guarantee and reports its own data. The virtual card has a shot at winning those decisions not because anyone convinced a buyer to pay using one, but because it’s the instrument a machine reaches for when the supplier has made everything else easy.

This is why the explosive growth probably won’t come from where the volume sits today. Not from the Fortune 500 treasury teams who already have working capital and lines of credit and process. It comes from the small and mid-sized businesses already buying in carts and already holding cards, and from the platforms that put their suppliers online, collapse the invoice into a checkout, and underwrite the buyer off-carted activity.

The long tail of SMB spend, the part the banks never served and the invoice never digitized, is exactly the part this supplier-led, agent-accelerated shift is built to reach. The penetration is low because suppliers only recently had the tools and the reason to move. Now they have both.

In this world, the invoice doesn’t get improved. It gets booted, left behind by the suppliers who moved to where the buyers were going, until it looks as quaint as the typewriter that once tapped out the checks that used to pay them. The cart is what replaces it, the agent is what runs it, and the smart credential is what carries the money through.

That’s not only the future of B2B payments. It’s the end of the artifact that defined its past.

Until NEXT time.

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