Accounts Payable Process: From Invoice to Payment

At its core, the AP process is simple: receive invoice, verify it's legitimate, get approval, pay vendor. But as companies grow, this simple process accumulates complexity: more vendors, more approvers, more payment methods, more controls.

The goal is to build a process that scales—handling higher volumes without proportionally more effort—while maintaining accuracy and control.

The Complete AP Workflow

Step 1: Invoice Receipt

Invoices arrive through multiple channels:

• Email: Most common; requires monitoring a dedicated AP inbox
• Vendor portal: Some vendors require you to retrieve invoices from their system
• Mail: Less common but still used by some vendors
• EDI: Electronic data interchange for high-volume vendor relationships

Best practice: Centralize all invoice receipt to a single location (AP inbox or portal) to ensure nothing gets lost.

Step 2: Invoice Capture and Data Entry

Extract key data from each invoice:

• Vendor name and details: Match to vendor master record
• Invoice number: Unique identifier for duplicate detection
• Invoice date: When vendor generated the invoice
• Due date: When payment is expected
• Amount: Total and line-item breakdown
• GL coding: Which expense accounts to hit

Step 3: Verification and Matching

Before approval, verify the invoice is legitimate:

• Vendor verification: Is this a known, approved vendor?
• Duplicate check: Has this invoice number been processed before?
• PO matching: Does invoice match a purchase order (if applicable)?
• Receiving confirmation: Were goods/services received?
• Amount verification: Does invoice match agreed pricing?

Step 4: Approval Routing

Route invoice to appropriate approver(s) based on:

• Amount thresholds: Higher amounts require higher-level approval
• Department: Route to department that incurred expense
• Expense type: Certain categories may require specific approval
• Budget status: Over-budget items may need additional approval

Step 5: Payment Scheduling

Once approved, schedule payment based on:

• Payment terms: Pay on due date, not before (unless discount applies)
• Payment run schedule: When is next scheduled payment batch?
• Cash position: Is cash available for payment?
• Early payment discount: Is it worth paying early for discount?

Step 6: Payment Execution

Execute payment via appropriate method:

• ACH: Default for most domestic payments (low cost, 1-3 days)
• Wire: For urgent or large payments (same-day, higher cost)
• Check: Only when required (slow, expensive, fraud risk)
• Virtual card: Where accepted (earns rebates)

Step 7: Recording and Reconciliation

• Record payment in accounting system
• Clear invoice from AP aging
• Bank reconciliation to match cleared payments
• Archive documentation for audit trail

Controls and Segregation of Duties

AP is a common fraud target. Controls prevent both internal fraud and external attacks.

Core Controls

• Vendor master control: Limit who can add/modify vendors in the system
• Segregation: Person who enters invoice shouldn't approve payment
• Approval authority: Define who can approve what amounts
• Dual authorization: Require two approvers for payments above threshold
• Bank change verification: Verify any vendor bank detail changes by phone

Segregation at Small Scale

With limited staff, full segregation may not be possible. Compensating controls:

• Owner/CFO reviews: Executive reviews all payments before execution
• Bank notifications: Real-time alerts for all outgoing payments
• Regular reconciliation: Frequent bank reconciliation catches anomalies
• Surprise audits: Periodic detailed review of AP transactions

Vendor Management

Effective vendor management improves AP efficiency and reduces risk.

Vendor Onboarding

• W-9 collection: Required for 1099 reporting
• Bank verification: Verify bank details before first payment
• Contact information: Who to call with questions
• Payment preferences: Preferred payment method
• Terms agreement: Document agreed payment terms

Ongoing Management

• Information updates: Process for updating vendor details securely
• Performance tracking: Track vendor reliability, quality, responsiveness
• Terms review: Periodically review and renegotiate terms
• Vendor rationalization: Consolidate to fewer vendors for better terms

Process Metrics

Measure AP performance to identify improvement opportunities.

Efficiency Metrics

• Invoice processing time: Days from receipt to approval (target: <5 days)
• Invoices per FTE: Volume handled per person (benchmarks vary by industry)
• Touchless rate: % of invoices processed without manual intervention
• Exception rate: % of invoices requiring special handling

Accuracy Metrics

• Error rate: % of invoices with processing errors (target: <2%)
• Duplicate payment rate: Duplicates as % of total (target: <0.1%)
• First-time match rate: % matching PO without adjustment

Financial Metrics

• DPO (Days Payable Outstanding): Average days to pay; track vs. terms
• Early payment discount capture: % of available discounts taken
• Cost per invoice: Total AP cost divided by invoice volume

Common AP Problems and Solutions

Invoice Bottlenecks

Problem: Invoices sit waiting for approval.

• Solution: Escalation rules—if not approved in X days, escalate to backup
• Solution: Mobile approval—let approvers handle on phone
• Solution: Auto-approval for recurring, consistent invoices

Duplicate Payments

Problem: Same invoice paid twice.

• Solution: System duplicate detection on invoice number
• Solution: Fuzzy matching on amount + vendor + date
• Solution: Pre-payment review of payment batch

Missing Invoices

Problem: Invoices don't make it into the system.

• Solution: Single receipt point (dedicated AP email)
• Solution: PO-based accruals identify missing invoices
• Solution: Vendor portal with invoice upload

Coding Errors

Problem: Expenses coded to wrong accounts.

• Solution: Default coding by vendor
• Solution: Limited chart of accounts options
• Solution: Review of unusual coding combinations

Building an Efficient AP Process

Foundation: Technology

• AP automation platform (Bill.com, Ramp, or accounting software built-in)
• Bank integration for payment execution
• Accounting software integration for GL posting

Process: Standardization

• Documented workflow with clear ownership at each step
• Defined approval matrix by amount and type
• Regular payment schedule (e.g., weekly runs)
• Exception handling procedures

People: Clear Roles

• Who receives and enters invoices
• Who reviews and codes
• Who approves at each level
• Who executes payments
• Who reconciles and resolves issues