Start building with the BILL API

Integrate with the easy-to-use BILL API and leverage our trusted B2B payments platform to send and receive payments for your business.

With the new BILL v3 API, we have upgraded a wide range of BILL AP and AR features. In addition, receive real-time event notifications with the new BILL webhooks.

❗️Changes to BILL API access

At this time, we are providing BILL API access only for select partners. Please reach out to your account manager for more information.

curl --request POST \
--url '' \
--header 'content-type: application/json' \
--header 'devKey: {developer_key}' \
--header 'sessionId: {session_id}' \
--data '{
  "vendorId": "{vendor_id}",
  "dueDate": "2024-12-31",  
  "billLineItems": [{
    "amount": 149.00,
    "description": "USB audio interface"
    "amount": 79.99,
    "description": "Drum foot pedal"
  "invoice": {
    "invoiceNumber": "202401",
    "invoiceDate": "2024-12-31"

Building blocks for developers

Create custom branded experiences with end-to-end Accounts Payable (AP) and Accounts Receivable (AR) workflows at scale.

Safely build and test with API calls in our sandbox environment to confirm your expectations.

Deploy to production when your integration is ready for your customers.

The new BILL v3 API

Learn about what is new with the BILL v3 API, including BILL webhooks.

What's new →

BILL webhooks →

API reference

View sample code in your choice of language and test sandbox API calls in the documentation.

v2 API reference →

v3 (BETA) API reference →


Step-by-step walkthroughs for use cases like paying a vendor and sending a customer invoice.

v2 recipes →

v3 (BETA) recipes →

Why integrate with BILL?

Leading payments platform

Use the BILL API to process high volumes of payments simultaneously. Leverage our automatic syncs and remove manual data entries with QuickBooks, Intacct, NetSuite, Dynamics, Xero and other integrations.

Faster & more efficient payments

We facilitate your AP process with faster electronic payments or standard checks. Your AR customers receive and pay invoices digitally. You pay or get paid in half the time as compared to paper-based processes.

Built with your security in mind

We manage over $70B annually and take financial security seriously. All data in transit is encrypted using industry standard Transport Layer Security (TLS).