Automate Expense Reimbursement Integration with Payroll and Accounting Systems

Implementation: Two Integration Approaches for Different Customer Workflows

Approach A: Payroll Integration via Compensation API

API Endpoint: POST https://api.getknit.dev/v1.0/hr.employees.compensation.update

Supported Platforms: 13 payroll systems including ADP Workforce Now, Paychex Flex, Gusto, Paylocity, Namely, Rippling, BambooHR Payroll, UKG Pro, Hibob, Workday, SAP SuccessFactors, Zoho People, Personio

Request Body Example:

{
  "employeeId": "emp_12345",
  "effectiveDate": "2025-01-15",
  "compensationType": "ONE_TIME",
  "amount": 2847.50,
  "currency": "USD",
  "description": "Expense Reimbursement - January 2025 Travel",
  "category": "REIMBURSEMENT"
}

Key parameters:

• employeeId: Employee identifier from HRIS sync
• effectiveDate: Date when compensation should be added to payroll (next payroll cycle date)
• compensationType: Must be ONE_TIME for reimbursements (not recurring)
• amount: Total approved expense amount from expense report
• description: Clear identification of reimbursement purpose for payroll records

Approach B: Accounting Integration via Invoice API

API Endpoint: POST https://api.getknit.dev/v1.0/accounting.invoice.create

Supported Platforms: 10 accounting systems including Xero, QuickBooks Online, NetSuite, Sage Intacct, Microsoft Dynamics 365 Business Central, Zoho Books, FreeAgent, FreshBooks, Odoo, Clear Books

Request Body Example:

{
  "vendorId": "vendor_emp_12345",
  "invoiceNumber": "EXP-2025-01-001",
  "invoiceDate": "2025-01-15",
  "dueDate": "2025-01-22",
  "lineItems": [
    {
      "description": "Business Travel - Client Meeting NYC",
      "quantity": 1,
      "unitPrice": 1247.50,
      "accountCode": "5100",
      "taxRate": 0
    },
    {
      "description": "Meals and Entertainment - Client Dinner",
      "quantity": 1,
      "unitPrice": 350.00,
      "accountCode": "5200",
      "taxRate": 0
    },
    {
      "description": "Ground Transportation - Taxi/Rideshare",
      "quantity": 1,
      "unitPrice": 150.00,
      "accountCode": "5110",
      "taxRate": 0
    }
  ],
  "currency": "USD",
  "status": "AWAITING_APPROVAL"
}

Key parameters:

• vendorId: Employee set up as vendor in accounting system (requires pre-provisioning)
• lineItems: Individual expense categories mapped to chart of accounts codes
• accountCode: GL account for each expense type (5100=Travel, 5200=Meals, etc.)
• status: Typically AWAITING_APPROVAL to route through AP approval workflow

Step 3: Handle Expense Category Mapping and Chart of Accounts

Regardless of integration approach, expense categories from your travel management platform must map to financial system coding structures. This ensures accurate financial reporting and budget tracking.

Expense category mapping examples:

Expense Category (T&E Platform)	Payroll Category	GL Account Code (Accounting)	Typical Description
Airfare	REIMBURSEMENT	5100 (Travel Expense)	Business Travel - Airfare
Hotel	REIMBURSEMENT	5105 (Lodging)	Business Travel - Accommodation
Meals	REIMBURSEMENT	5200 (Meals & Entertainment)	Business Meals
Ground Transportation	REIMBURSEMENT	5110 (Local Transportation)	Taxi/Rideshare/Parking
Office Supplies	REIMBURSEMENT	6100 (Office Expenses)	Business Supplies Purchase
Equipment	REIMBURSEMENT	1500 (Fixed Assets)	Equipment Purchase (Capitalized)

Key APIs and Data Models for Reimbursement Integration

Integration Type	API Endpoint	Platform Support	Key Considerations
Payroll Integration	POST /v1.0/hr.employees.compensation.update	13 payroll platforms	Use ONE_TIME compensation type. Map to next payroll cycle date. Combine multiple expense reports per employee if platform limits compensation entries.
Accounting Integration	POST /v1.0/accounting.invoice.create	10 accounting platforms	Requires employee vendor records pre-configured. Map expense categories to chart of accounts. Include line item detail for audit trail.
Employee Vendor Setup	POST /v1.0/accounting.vendor.create	Same 10 accounting platforms	Pre-provision employees as vendors in accounting system. Required before invoice creation.

Workflow decision matrix:

• Customer processes reimbursements in payroll: Use Compensation API → Add as ONE_TIME payment in next payroll cycle
• Customer processes via accounts payable: Use Invoice API → Create invoice for AP approval and payment
• Customer uses both methods: Allow configuration per employee or department (executives via payroll, contractors via AP)
• Multi-entity customers: Route to appropriate system based on employee entity or location assignment

Wrapping Up: Eliminate Manual Reimbursement Processing and Accelerate Employee Payments

Automated reimbursement integration transforms expense processing from a manual, multi-system workflow into a streamlined, error-free operation. By automatically pushing approved expense totals into payroll or accounting systems—whichever your customer uses—you eliminate data re-entry, reduce payment processing time, and ensure accurate financial reporting of employee expense reimbursements.

Key capabilities unlocked:

• Dual integration path support: Single implementation supports both payroll-based reimbursement (13 platforms) and accounts payable workflows (10 platforms)
• Automated payment processing: Approved expenses automatically populate in financial systems, eliminating manual data transfer and reducing reimbursement cycle time
• Accurate expense categorization: Map expense types to chart of accounts codes or payroll categories, ensuring correct financial reporting and budget tracking
• Platform-specific handling: Navigate platform limitations (Hibob's single compensation entry, Zoho Books' 2-item minimum, NetSuite's multi-entity requirements) automatically
• Audit trail preservation: Line-item detail flows from expense reports to financial records, maintaining complete audit trail from submission to payment
• Multi-entity support: Route reimbursements to correct financial system based on employee entity, location, or organizational assignment