Virtual investor session June 22, 2022

Introduction John T. Williams, Head of Investor Relations

Disclaimers Forward-Looking Statements This presentation includes “forward-looking statements” within the meaning of the “safe harbor” provisions of the United States Private Securities Litigation Reform Act of 1995. Forward-looking statements may be identified by the use of words such as “outlook,” “target,” “expect,” “will,” “forecast,” or other similar expressions that predict or indicate future events or trends or that are not statements of historical matters. These forward-looking statements include, but are not limited to, statements regarding Billtrust’s financial outlook, guidance and forecasts of Billtrust’s financial and performance metrics, the potential benefits, value and the commercial attractiveness to its customers of Billtrust’s products and services, and Billtrust’s opportunity and ability to grow and scale its business. These statements are based on various assumptions, whether or not identified in this presentation, and on the current expectations of Billtrust’s management and are not predictions of actual performance. These forward-looking statements are provided for illustrative purposes only and are not intended to serve as, and must not be relied on by any investor as, a guarantee, an assurance, a prediction or a definitive statement of fact or probability. Actual events and circumstances are difficult or impossible to predict and may differ from assumptions. Many actual events and circumstances are beyond the control of Billtrust. These forward-looking statements are subject to a number of risks and uncertainties, including Billtrust’s ability to attract and retain customers and expand customers’ use of Billtrust’s services; market, financial, political and legal conditions; the impact of the COVID-19 pandemic on Billtrust’s business and the global economy; risks relating to the uncertainty of the projected financial and operating information with respect to Billtrust; risks related to future market adoption of Billtrust’s offerings; risks related to Billtrust’s marketing and growth strategies; risks related to expanding Billtrust’s operations outside the United States; risks related to Billtrust’s ability to acquire or invest in businesses, products, or technologies that may complement or expand its products or platforms, enhance its technical capabilities, or otherwise offer growth opportunities; the effects of competition on Billtrust’s future business; and the risks discussed in Billtrust’s Annual Report on Form 10-K for the fiscal year ended December 31, 2021 filed March 9, 2022, under the heading “Risk Factors” and other documents of Billtrust filed, or to be filed, with the Securities and Exchange Commission (“SEC”). If any of these risks materialize or any of Billtrust’s assumptions prove incorrect, actual results could differ materially from the results implied by these forward-looking statements. There may be additional risks that Billtrust presently does not know of or that Billtrust currently believes are immaterial that could also cause actual results to differ from those contained in the forward-looking statements. In addition, these forward-looking statements reflect Billtrust’s expectations, plans or forecasts of future events and views as of the date of this presentation. Billtrust anticipates that subsequent events and developments will cause Billtrust’s assessments to change. However, while Billtrust may elect to update these forward-looking statements at some point in the future, Billtrust specifically disclaims any obligation to do so. These forward-looking statements should not be relied upon as representing Billtrust’s assessments as of any date subsequent to the date of this presentation. Accordingly, undue reliance should not be placed upon the forward-looking statements. Non-GAAP Financial Measures Some of the financial information contained in this presentation has not been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”). Such financial information is identified as such within the presentation. Billtrust believes that the use of these non-GAAP financial measures provides an additional tool for management and investors to use in evaluating Billtrust’s actual and projected financial condition and operating results and trends in and in comparing Billtrust’s financial measures with other similar companies, many of which present similar non-GAAP financial measures to investors. Billtrust does not consider these non-GAAP measures in isolation or as an alternative to financial measures determined in accordance with GAAP. The principal limitation of these non-GAAP financial measures is that they exclude significant expenses and other amounts that are required by GAAP to be recorded in Billtrust’s financial statements. In addition, they are subject to inherent limitations as they reflect the exercise of judgments by management about which expense and other amounts are excluded or included in determining these non-GAAP financial measures. In order to compensate for these limitations, Billtrust presents non-GAAP financial measures in connection with GAAP results. Billtrust is not providing a reconciliation of its projected net revenue, adjusted gross profit, adjusted gross margin and adjusted EBITDA margin to the most directly comparable measure prepared in accordance with GAAP because it is difficult to reliably predict or estimate the relevant components without unreasonable effort due to future uncertainties that may potentially have significant impact on such calculations. You should review Billtrust’s Annual Report on Form 10-K for the fiscal year ended December 31, 2021 filed March 9, 2021, under the heading “Risk Factors,” and other documents of Billtrust filed, or to be filed, with the SEC.

Introduction John T. Williams, Head of Investor Relations Please submit questions to IR@billtrust.com

Today’s agenda Where we’ve been and where we’re going Flint Lane, Founder and CEO Talent update Jeanne O’Connor, Chief Talent Officer Product Greg Hanson, Chief Product Officer BPN and Digital Lockbox Nick Babinsky, General Manager, BPN Sales and go-to-market Jay Johnson, Chief Sales Officer Steve Lindeman, Chief Customer Officer Customer interview: Sunbelt Rentals Steve Pinado, President Finance update Mark Shifke, Chief Financial Officer Q&A Flint Lane, Steve Pinado, Mark Shifke

Where we’ve been and where we’re going Flint Lane, Founder and CEO

Why we went public Raise capital Accelerate growth, fund strategic R&D and S&M investment Renewed focus on channel relationships Strong balance sheet $300M raised Support M&A Establish deep capital reserve Drive higher margins Print to digital shift Improved monetization Reap scale efficiencies

Expectations vs. reality From our October 2020 investor deck: Our actual performance: Net revenue ($mm) Software and Payments Other $109 $132 $168 24% CAGR Net revenue ($mm) Note: Data as of 12/31/2021 unless otherwise specified; All financial metrics presented here, including net revenue and adjusted gross margin, are presented on a non-GAAP basis. An explanation of this measure and how it is calculated and a reconciliation to the comparable GAAP measure is included in the Appendix. 1 2022E revenue and adjusted gross profit estimates represent midpoint of our FY 2022 financial outlook 1

Expectations vs. reality From our October 2020 investor deck: Our actual performance: Adjusted gross profit ($mm) Gross profit ($mm) Adjusted gross margin 70.3% 73.1% 73.5% 27% CAGR 1 Note: Data as of 12/31/2021 unless otherwise specified; All financial metrics presented here, including net revenue and adjusted gross margin, are presented on a non-GAAP basis. An explanation of this measure and how it is calculated and a reconciliation to the comparable GAAP measure is included in the Appendix. 1 2022E revenue and adjusted gross profit estimates represent midpoint of our FY 2022 financial outlook

Global acquisitions Acquired October 2021 Credit and Collections SaaS solution Acquired February 2022 Connections to 70+ B2B and B2G e-invoicing networks

Key recent partnerships American Express American Express Merchant Services Partners with Billtrust to Offer Solutions to Supplier Receivables Challenges Arvest Arvest Bank Joins Billtrust’s Business Payments Network Avalara Avalara’s CertCapture Software Integrates with Billtrust to Securely Process, Collect, Validate, Store and Renew Compliance Documents Bottomline Bottomline Expands Network with Billtrust’s Business Payments Network Coupa Billtrust Announces Coupa as a Referral Partner and Business Payments Network (BPN) Provider JAGGAER JAGGAER and Billtrust to Deliver Invoicing Automation Karmak Karmak Announces Partnership with Billtrust to Enable Complete Accounts Receivable Management Procede Billtrust Partners with Procede Software to Speed Payments and Improve Cash Flow REPAY REPAY Scales B2B Payments Offerings with Billtrust Partnership

Looking aheadRich opportunity set going forward US and International Sales BPN and Digital Lockboxes and arming the channel for more widespread supplier adoption Surcharging Future potential acquisitions Selling to AP solutions providers more than just access to BPN

Talent update Jeanne O’Connor, Chief Talent Officer

Our values Customer Commitment What would the customer want? Invincibility We’re Billtrust, we can do anything Open-Mindedness Challenge the status quo Accountability & Ownership Fix the problem, not the blame Fiscally Responsible Spend money like it was your own Listen Actively You have two ears and one mouth, use them proportionally Family First We are not on this planet so we can work and make money Unique Individuals It’s all about our people Results Matter Get it done

Industry-leading employee culture 791 global employees across 7 countries 680 North America 111 Europe US Canada Netherlands Belgium Poland UK Germany Work from anywhere Boundaryless recruiting to find the best talent, regardless of geography Competitive advantage in a tight labor market Positioned for future market shifts Reduced office footprint 7 employee resource groups (ERGs) +77 Engagement score Top strengths Acceptance88/100 Billtrust makes it easy for people with diverse backgrounds to be accepted Team support87/100 I can get the help I need from my teammates and colleagues Manager85/100 I would recommend my manager to others

Environmental, Social, Governance (ESG) strategy & engagement Growing in alignment with our values ESG priorities Energy & GHGmanagement Data privacy & cybersecurity Integrity & transparency Employee engagement & wellbeing Work from anywhere produces 3x less emissions per employee Billtrust eSolutions saved 301 million paper invoices and 22 million paper checks from landfill in 2021 Diversity & inclusion Climate Launched Billtrust for Good employee giving program and six new Employee Resource Groups 41% of Q1 hires contributed to diversity goals Conducted materiality assessment in November 2021 Formalized executive sponsorship of ESG initiatives People Trust

7-year best places to work winner Where can we find the list of awards? Slide to be designed

Product update Greg Hanson, Chief Product Officer

The BilltrustPlatform

R&D main areas of focus Internationalization Unifiedpaymentsengine and rules Invoicedistribution andcompliance Analytics and reporting Simplified integrations

Surcharging as a Service Identifying approved cards Our technology automatically differentiates between all card types — credit, debit, prepaid and government issued — to maintain compliance. 30-day card brand notification We ensure merchants properly notify all relevant stakeholders — card brands and acquirers — in a timely fashion. Optimal surcharge rates Our engine automatically calculates the exact surcharge amount based on the transaction total, ensuring maximum rates are not breached and all card brand rules are being followed. Customer surcharge awareness Billtrust automatically processes the purchase amount and credit card fees as one transaction at checkout and provides you with the most updated proper notice protocols. Evolving state legislation We diligently oversee evolving and Independent state regulations so merchants with national, omnichannel presence remain compliant. Card brand rules We continuously navigate card brands’ multifaceted directives so merchants can maximize their margins with peace of mind.

Attachment rates reflect value gains from combining products ⅔ 64% of all customers purchase Invoicing of all Invoicing customers add Payments Invoicing & Payments customers most often include BPN as third product Next most common third product is Cash Application

BPN and Digital Lockbox Nick Babinsky, GM, Business Payments Network

Let’s talk paper checks in B2B Of the $25 trillion in spend that is exchanged between businesses in the US each year, AFP estimates1 that 42% remains on check. 1 Source: 2019 AFP® Payments Cost Benchmarking Survey.

Electronic payments are challenging for AR

$680,369,317 in annual electronic remittances 1.06M invoices paid $2,734,423,674 in annual electronic remittances 500K invoices paid $45,115,203 in annual electronic remittances 90K invoices paid Examples of receivables volume by email & AP portals

Will the industry align around a standard? EDI ACH CTX ISO 20022 Real-timepayments Blockchain

Growth AP automation amplifies pain for AR B2B AR Teams

BPN’s Digital Lockbox BPN captures remittances from connected payables and procurement platforms as well as emails, file, and portals across card, ACH, and wire.

The power of our network BPN connects major participants and drives high volumes of digital transactions BPN Buyers Suppliers Banks Fintechs AR Providers Gateways & acquirers Treasury banks

How BPN works PaymentInstruction Fees charged to buyer-side participants to eliminate paper costs and drive electronic payment volume BPN Buyers Suppliers Payables Platform Supplier Sponsors Settlement& Reconciliation Fees charged to supplier-side participants to eliminate paper costs and drive automated AR

Business Payments Network (BPN) TPV Trend ($ Billions) 86% YoY Growth Card Card ACH/Wire Business Payments Network (BPN) is Billtrust’s leading two-sided B2B payments network that connects buyers and suppliers, and includes both BPN Card volume and BPN 3.0 ACH & Wire volumes. Card TPV is the dollar value of customer card payment transactions that Billtrust processes on its platform during a particular period. TPV- ACH/Wire is the dollar value of customer ACH or wire payment transactions that Billtrust processes on its platform during a particular period. 50% YoY 363% YoY

A conversation on go-to-market Flint Lane, Chief Executive Officer Jay Johnson, Chief Sales Officer Steve Lindeman, Chief Customer Officer

Sunbelt Rentals fireside chat Steve Pinado, President, Billtrust John Schoenberger, SVP Finance, Sunbelt Rentals

Financial update Mark Shifke, Chief Financial Officer

Financial performance highlights Full Year Software & Payments Revenue($ millions) 24% CAGR since 2017 Full Year Total Payment Volume (TPV)2($ billions) 35% CAGR since 2017 34% Q1 2022 adjusted Software & Payments YoY revenue growth 73% Q1 2022 adjusted gross margin 45% Q1 2022 TotalPayment VolumeYoY growth 68% Q1 2022 Direct Card Revenue2 YoY growth Full Year Adjusted Gross Margin1 900 bps expansion since 2017 Note: Data as of 12/31/2021 unless otherwise specified. 1 Adjusted Gross Margin and Direct Card Revenue are non-GAAP financial measures. An explanation of these measures and how they are calculated and a reconciliation to the comparable GAAP measure is included in the Appendix. 2 Refer to Appendix for a definition of Total Payment Volume ("TPV"). Q1 2022 Highlights

FY22 Outlook & Long-term Operating Model – Unchanged 1 Net revenue, adjusted gross margin and adjusted EBITDA margin are non-GAAP financial measures. An explanation of these measures and how they are calculated and a reconciliation to the comparable GAAP measure is included in the Appendix. Billtrust does not provide a reconciliation of forecasted measures because it is difficult to reliably predict or estimate the relevant components without unreasonable effort due to future uncertainties that may potentially have significant impact on such calculations, and providing them may imply a degree of precision that would be confusing or potentially misleading. 2 Annual growth, adjusted for one-time and unusual items including customer losses. (annual growth rates unless otherwise noted) We define “mid-term” as 3-5 years, and “long-term” as beyond 5 years. FY19 Actual FY20 Actual FY21 Actual FY22 Outlook *midpoint, includes M&A Mid-term target *excludes M&A Long-term target *excludes M&A Net Revenue1 21% 13% 21% 28% 20-25% ~20% Software and Payments Segment Revenue2 28% 18% 28% 31% 25-30% 20%+ Adjusted Gross Margin1 67% 70% 73% 73.5% 75-80% 80%+ Adjusted EBITDA Margin1 (11)% (2)% (10)% (9)% 8-12% 25%+

Full Year 2022 Modeling Considerations Net Revenue, Adjusted Gross Profit, Adjusted Gross Margin and Adjusted EBITDA are non-GAAP financial measures. Billtrust does not provide a reconciliation of forecasted measures because it is difficult to reliably predict or estimate the relevant components without unreasonable effort due to future uncertainties that may potentially have significant impact on such calculations, and providing them may imply a degree of precision that would be confusing or potentially misleading. Fully diluted shares include all current potentially issuable shares tied to vested, in-the-money employee options and RSUs; the company has no remaining outstanding warrants. Expected quarterly cadence and additional details Net Revenue1 We expect the following quarterly net revenue cadence for the remainder of 2022: Q2: 23-25% of full-year net revenue recognized; Q3: 25-27%; Q4: 27-29% (Q1: 22% reported) Adjusted Gross Profit1 and Adjusted Gross Margin1 For both items, we still expect 1H to be below, and 2H to be above, the midpoint. Adjusted EBITDA1 We expect Q2 will look like Q1, followed by significant sequential improvement in both Q3 and Q4. Share Count As of 3/31/22: Basic: 163 million; Fully diluted2: 168 million

Current investor conversations Legacy SPAC concerns Path to profitability Current macro environment

Path to profitability 1 Billtrust does not provide a reconciliation of forecasted measures because it is difficult to reliably predict or estimate the relevant components without unreasonable effort due to future uncertainties that may potentially have significant impact on such calculations and providing them may imply a degree of precision that would be confusing or potentially misleading. Recent developments Our profitability timeline is the #1 topic brought up by investors in our recent conversations. We are responsive to changing market conditions and we are able to pivot accordingly. Our updated path We are now targeting Q2-Q3 2023, accelerated from 2H 2023-1H 2024, to be adjusted EBITDA positive.1 Given this accelerated timeframe, we expect to be adjusted EBITDA positive for full year FY 2024.1

Q&A Flint Lane, Steve Pinado, and Mark Shifke Please submit questions to IR@billtrust.com

Appendix

Definitions Net revenue (non-GAAP) is defined as total revenues less reimbursable costs revenue. Reimbursable costs revenue consists primarily of amounts charged to customers for postage (with an offsetting amount recorded as a cost of revenue) which we do not consider internally when monitoring operating performance. Adjusted gross profit (non-GAAP) is defined as total revenues less total cost of revenues, excluding depreciation and amortization, plus stock-based compensation expense included in total cost of revenues. Adjusted gross margin (non-GAAP) is defined as adjusted gross profit (non-GAAP) divided by total revenues less reimbursable costs revenue, or net revenue (non-GAAP). Adjusted EBITDA (non-GAAP) is defined as net loss, plus (1) income tax expense (benefit), (2) changes in the fair value of financial instruments that do not meet the criteria to be classified as equity, (3) interest expense and loss on extinguishment of debt, (4) depreciation and amortization, (5) stock-based compensation expense, (6) impairment, restructuring, and related costs, (7) acquisition and integration costs, (8) other capital structure transaction costs, and (9) other non-operating expense (income). Adjusted EBITDA margin (non-GAAP) is defined as adjusted EBITDA (non-GAAP) divided by total revenues less reimbursable costs revenue, or net revenue (non-GAAP). Direct Card Revenue (“DCR”; non-GAAP) is defined as subscription, transaction, and services revenues, less revenues generated from segments other than software and payments (i.e. software and payments segment revenue), less software and payments segment transaction revenue unrelated to card processing and all subscription revenue. Direct card revenue (non-GAAP) includes variable transactional fee revenue associated with card payments on our electronic payments processing platforms and is a subset of our software and payments segment revenues. Software and Payments (ex-DCR) Revenue (non-GAAP) is defined as software and payments segment transaction revenue unrelated to card processing and all subscription revenue. Total Payment Volume (TPV) is the dollar value of customer payment transactions that we process on our platform during a particular period. TPV is made up of two payment categories: TPV - ACH/Wire - payments made via our software, portals, gateways, and our Business Payments Network that are processed via ACH or wire transfers; and TPV - Card - payments through our software, portals, gateways, and third-party processors, and includes our payment facilitator (“PayFac”) customers.

Reconciliation of non-GAAP net revenue, non-GAAP adjusted gross profit, & non-GAAP adjusted gross margin - Annual

Reconciliation of non-GAAP adjusted EBITDA and non-GAAP adjusted EBITDA margin - Annual

Reconciliation of non-GAAP net revenue, non-GAAP adjusted gross profit, & non-GAAP adjusted gross margin - Quarterly

Reconciliation of non-GAAP adjusted EBITDA and non-GAAP adjusted EBITDA margin - Quarterly

Reconciliation of Full Year 2022 Outlook (Mid-point)

Reconciliation of Direct Card Revenue Metrics: Annual and Quarterly

Reconciliation of FY 2021 Software and Payments Segment Revenue Growth (Adjusted for One-Time Customer Loss)

Reconciliation of Q1 2022 Software and Payments Segment Revenue Growth (Adjusted for One-Time Customer Loss)