The BILL v3 API follows the REST architecture. We use all the standard REST verbs (GET, POST, PUT, PATCH, and DELETE) and provide HTTP response codes.

BILL offers a comprehensive sandbox environment where you can test workflows, from creating bills to completing AP payments, without moving real money. See Sandbox vs Production to learn about the two BILL development environments.

Workflow	API	What can you do?
AP	Vendors Bills Bill approvals Payments Vendor credits	Create bills & pay vendors at scale with a wide range of payment methods. Create bulk bills & bulk payments. Generate payment disbursement reports.
AR	Customers Invoices Charge customers Credit memos Record payments	Generate invoices & send invoices to get paid by customers. Charge authorized customers for invoices. Record offline payments received outside the BILL platform.
BILL Network	BILL Network	Connect with over 7 millions of customers and vendors in the BILL Network. BILL automatically enables payments to connected vendors with ACH, virtual card, or check.
S&E	Budgets Cards Transactions Reimbursements	Build with card & expense management services. Set up budgets, users, & virtual cards. Manage transactions & reimbursements.
Webhooks	Webhooks	Subscribe to & receive real-time notifications for AP & AR events and S&E events.

Sign-up

Sign-up and generate a developer key to begin testing with the BILL AP & AR API. With this key, you can build with the AP, AR, BILL Network, and webhook workflows. See Sandbox API sign up for more information.

Spend & Expense API

A BILL S&E API token is required for you to begin testing with the Spend & Expense API. You can build with budgets, users, and virtual cards. In addition, you can manage transactions and reimbursements. See Authentication with Spend & Expense API token for more information.

Partner operations

As a BILL partner, you can perform partner-level operations, which include creating an organization, and then creating and managing users for that organization. See BILL partner operations for more information.

Documentation resources

Learn more about the BILL v3 API services with a range of documentation resources.

Section	Description
API guides	Introduction to the core BILL v3 API concepts.
API reference	Complete list of BILL v3 API endpoints with request & response fields explained.
Postman Collection	Simply fork the BILL Postman Collection & begin testing with different BILL v3 API workflows.
Video tutorials	Developer tutorial videos to learn how to build with different BILL v3 API workflows.
Common API error codes	Common BILL error messages for API operation failures.
FAQs	Frequently Asked Questions (FAQs) about the BILL v3 API workflows.
BILL Help Center	BILL knowledge base with help & support resources for BILL customers.
BILL Developer Terms	Legal agreement between BILL and any organization you identify in your registration with BILL.