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Notice
Special holiday hours in effect, December 2025 through January 2026. More information.

For Vendors

Office of the Chief Financial Officer
Accounting Operations Office

(202) 707-5225
accountspayable@loc.gov

IPP Implementation at the Library of Congress

The Library of Congress uses the Invoice Processing Platform (IPP) to facilitate the electronic exchange of purchase orders (POs), invoices, and payment information to its suppliers of goods and services. IPP is a service provided by the US Treasury’s Bureau of the Fiscal Service designed to help streamline the order-to-pay process. As a vendor to the Library, IPP is available for you to use at no cost to your company. By using IPP, vendors can receive electronic purchase orders and send electronic invoices; either through file exchange or by pulling data for invoices directly from POs. IPP provides online access to invoice status and payment information. Additional information and vendor training materials are available on-line at www.IPP.gov.

Vendors will not be able to submit invoices using IPP for contracts with National Library Service for the Blind and Print Disabled (NLS). The Library will notify vendors as these contracts become available to invoice in IPP.

Until October 1, 2016, participation will be voluntary. In order to enroll vendors must send an email to accountspayable@loc.gov indicating their interest in participating. Please see the Registration Letter below for additional details regarding the registration process.

Beginning on August 28, 2023, Multifactor Authentication (MFA) will be required to login to IPP. Multi-factor authentication strengthens account security by requiring two factors to confirm user identity. To support MFA for non-PIV/CAC users, e.g., vendors, IPP is partnering with third-party credential service providers (CSPs) such as ID.me . All vendor users will be required to verify their identity through a CSP before accessing IPP on or after August 28th.

In the coming weeks, IPP will send an email (from info@IPP.Fiscal.Treasury.gov) to all vendor users informing them of the anticipated changes to the IPP.

Questions or concerns may be directed to the Accounting Operations Office at 202-707-5225, or e-mail to accountspayable@loc.gov.

Submitting Invoices for Payment

Invoices must be sent electronically in accordance with the terms specified in the purchase order or contract. Invoices submitted by email should be attached to a message addressed to accountspayable@loc.gov, and the word “Invoice” in the subject line. The following formats are accepted: Word, WordPerfect, Excel, PDF (Adobe), and HTML.

Please do not mail or fax additional copies of invoices which have been sent electronically.

Updating Vendor Information

Vendors which are registered with System for Award Management (SAM/CCR) must access SAM to update information. Otherwise, to update address or banking information please click on the link below and complete the form. The form may be faxed to (202) 707-2829, or e-mailed to accountspayable@loc.gov.