broaden Olo’s platform capabilities and allow restaurants to connect to apps and technologies that streamline operations, improve efficiency, enhance guest experience, and increase profitability. The acquisition, for which we paid approximately $49.4 million in cash, closed on March 4, 2022 pursuant to the terms set forth in the merger agreement. Key Factors Affecting Our Performance Add New Large Multi-Location and High-Growth Restaurant Brands We believe there is a substantial opportunity to continue to grow our customer base across the U.S. restaurant industry, adding to our over 600 existing brands across approximately 82,000 active locations as of March 31, 2022, up from approximately 69,000 active locations as of March 31, 2021. We define an “active location” as a unique restaurant location that is utilizing one or more modules in a given quarterly period. We consider each specific restaurant brand to be a customer, even if owned by a parent organization that owns multiple restaurant brands, and define active locations as a location where at least one of our modules is deployed. We intend to continue to drive new customer growth by leveraging our brand and experience within the industry, and expanding our sales and marketing efforts. We have also historically pursued and will continue to target the most well-capitalized, fastest-growing restaurant brands in the industry. Our ability to attract new customers will depend on a number of factors, including our ability to innovate, the effectiveness and pricing of our new and existing modules, the growth of digital ordering, and the success of our marketing efforts. Expand Within Our Existing Customer Base Our large base of enterprise customers and transactional SaaS revenue model represent an opportunity for further revenue expansion from the sale of additional modules, and the addition of new restaurant locations. A key factor to our success in executing our expansion strategy will be our ability to retain our existing and future restaurant customers. Our exclusive, long-term, direct digital ordering contracts with our customers provide us the opportunity to form unique, trusted partnerships with our restaurant brands, further enhancing our ability to satisfy and retain our customers. Our contracts typically have initial terms of three years or longer, with continuous one-year automatic renewal periods, providing visibility into our future performance. One indication of our ability to grow within our customer base through the development of our products that our customers value is our average revenue per unit, or ARPU. We calculate average revenue per unit by dividing the total platform revenue in a given period by the average active locations in that same period. We believe this demonstrates our ability to grow within our customer base through the development of our products that our customers value. The following summarizes our ARPU and number of active locations for the three months ended, or as of, each of the dates presented. Three Months Ended Mar ch 31, 2022 2021 Average Revenue Per Unit $ 516 $ 525 Ending Active Locations 82,000 69,000 A further indication of the propensity of our customers to continue to work with and expand their relationship with us over time is our dollar-based net revenue retention rate, or NRR, which compares our revenue from the same set of active customers in one period to the prior year period. We calculate dollar-based NRR as of a period-end by starting with the revenue, defined as platform revenue, from the cohort of all active customers as of 12 months prior to such period-end, or the prior period revenue. We then calculate the platform revenue from these same customers as of the current period-end, or the current period revenue. Current period revenue includes any expansion and is net of contraction or attrition over the last 12 months, but excludes platform revenue from new customers in the current period. We then divide the total current period revenue by the total prior period revenue to arrive at the point-in-time dollar- based NRR. We believe that NRR is an important metric demonstrating our ability to retain our customers and expand their use of our modules over time, proving the stability of our revenue base and the long-term value of our customer relationships. For the three months ending March 31, 2022, we maintained an NRR of approximately 107%. While we maintained an NRR over 120% throughout 2021, 2020, and 2019, we observed a decline in NRR this quarter as we lapped the last pre-vaccination period of the COVID-19 pandemic, during which time order volumes were elevated, and the final quarter operating under our prior DoorDash agreement. We expect to return to NRR in excess of 120% in the near term as customers continue to adopt additional product modules such as Olo Pay and our FOH and Customer Engagement solutions. 25