Automating High-Value Vendor Invoices: Using AI to Transition Bulk Spend to Card

Types of vendor spend

In the ecosystem of B2B payments, vendor spend typically falls into two major categories:

1. Recurring expenses: High-frequency subscriptions that bill on a fixed schedule (e.g., SaaS tools or utility bills). We previously covered this type of spend type in a another blog post.‍
2. Invoice-based payments: Payments for specific service periods, inventory, or large-scale multi-year contracts.

While recurring spend is a natural fit for card adoption, the real "whale" of commercial payments lies in invoice-based spend. Today, leaders in the industry like Ramp are already adopting agentic AI to assist clients with paying vendor invoices. In this article, we explore how automation and Agentic AI are enabling a seamless transition of these high-value vendor invoices to card, unlocking significant revenue and efficiency for issuers and their clients.

Why target vendor invoice spend?

While recurring payments offer frequency, invoice-based spend offers scale. Targeting this segment provides several strategic advantages:

• Higher Interchange Revenue: Companies spend bulk sums on inventory, major software agreements, or multi-year deals. Because the transaction sizes are massive, the interchange earned from these payments is far more lucrative than a standard recurring subscription.
• Capturing Untapped Volume: These are often the most difficult expenses to move to card because many vendors prefer ACH or wire to avoid fees.
• The Intelligence Requirement: Success in this area requires being "smart." You need systems that can identify which vendors actually accept card and which do not, ensuring a high success rate for the end user.

Payment Link Automation

One of the most common ways to pay a vendor invoice is through a public payment portal. These links are often hosted by a payment processor like Stripe, Square, or Intuit, and require the user to manually choose their payment modality.

How Browser AI Agents Solve the Friction

By utilizing Browser AI Agents—such as Browser-use or Claude combined with Stagehand or Playwright—the payment process can be fully automated.

• The Workflow: Once a client provides their login or invoice details, the system spins up a remote browser (via providers like Hyperbrowser or Browserbase) and logs into the portal on the client’s behalf.
• Solving Complex Flows: These agents are capable of navigating multi-page checkouts and handling real-world obstacles like CAPTCHA solving that typically break traditional automation scripts.

Vendor Card Delivery via Form or Email

Not all vendors have a dedicated portal. Many legacy or mid-market companies accept card payments through more manual channels, such as an Accounts Receivable (AR) email address or via a phone call.

• Agentic Voice AI: For vendors who only take card details over the phone, modern voice AI can complete these flows securely. These agents can call the vendor, navigate phone trees, and provide card details through a secured line.
• Secure Links: Alternatively, AI can automate the delivery of card details via secure forms or encrypted email channels, ensuring the data is handled according to PCI standards while removing the manual work for the accounting team.

The Billing Portal Challenge

Major vendors, such as Salesforce, provide dedicated billing portals where clients manage invoices for quarterly or yearly service periods. Automating these presents a two-part challenge:

1. Permissioned Access: Gaining authorized entry into the client’s specific vendor account.
2. Updating Payment Methods: Automatically navigating to the correct "Payment Settings" menu and updating the preferred card on file for future billing cycles.

Solving Portal Authentication

Because there are no common APIs or OAuth mechanisms to access billing portals today, browser automation is the only scalable solution.

A robust solution involves collecting user login information through a secure workflow and then using a remote browser infrastructure. AI agents are critical here because they can handle the multitude of login flows present in modern security:

• SSO and Login with Google: Navigating complex OAuth redirects.
• 2FA Challenges: Managing real-time SMS or email-based multi-factor authentication triggers.
• Passkeys: Managing device-level authentication or through a password manager

Driving Card Adoption with Vendor Invoices

Our experience shows that these three methods—Payment Link Automation, Manual Delivery, and Billing Portal Updates—represent 80-90% of all bill pay options where a card can be used.

For companies focused on driving more bill pay volume to card, it is no longer enough to just offer a virtual card; you must support the automation infrastructure that makes using that card the path of least resistance.

Rutter has developed a supplier enablement solution designed to trigger these workflows, enable permissioned access to portals, and switch payment methods at scale.

Ready to move your vendor spend to card? Book a demo with Rutter today.

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