Good afternoon. My name is Aaron, and I will be your conference operator for today. At this time, I would like to welcome everyone to the Cloudflare Q1 2025 earnings call. All lines have been placed on mute to prevent any background noise, and after the speaker's remarks, there will be a question-and-answer session. If you would like to ask a question during this time, simply press star, followed by the number one on your telephone keypad. If you'd like to withdraw your question at any time, it's just that star, followed by number one again. We do ask that you please limit yourself to an initial question and then a single follow-up when you're given the opportunity to speak. Thank you. With that, I'm pleased to turn the call over to Phil Winslow, VP of Strategic Finance, Treasury and Investor Relations. Phil, please begin.
Thank you for joining us today to discuss Cloudflare's financial results for the first quarter of 2025. With me on the call, we have Matthew Prince, Co-founder and CEO, and Thomas Seifert, CFO. Michelle Zatlyn, Co-founder and President, is traveling internationally and will not be available on today's call. By now, everyone should have access to our earnings announcement. This announcement, as well as our supplemental financial information, may be found on our Investor Relations website. As a reminder, we will be making forward-looking statements during today's discussion, including, but not limited to, our customers, vendors, and partners, operations and future financial performance, our anticipated product launches, and the timing and market potential of those products, our anticipated future financial and operating performance, and our expectations regarding future macroeconomic conditions.
These statements and other comments are not guarantees of future performance and are subject to risks and uncertainty, much of which is beyond our control. Our actual results may differ significantly from those projected or suggested in any of our forward-looking statements. These forward-looking statements apply as of today, and you should not rely on them as representing our views in the future. We undertake no obligation to update these statements after this call. For a more complete discussion of the risks and uncertainties that could impact our future operating results and financial condition, please see our filings with the SEC, as well as in today's earnings press release. Unless otherwise noted, all numbers we talk about today, other than revenue, will be on an adjusted Non-GAAP basis.
You may find a reconciliation of GAAP to non-GAAP financial measures that are included in our earnings release on our Investor Relations website. For historical periods, a GAAP to non-GAAP reconciliation can be found in the supplemental financial information referenced a few moments ago. We would also like to inform you that we will be participating in JPMorgan's 53rd Annual Global Technology, Media, and Communications Conference on Tuesday, May 13th. Now, with that, I'd like to turn the call over to Matthew.
Thank you, Phil. We had a strong start to 2025. We achieved revenue of $479.1 million, up 27% year over year. We closed the quarter with 3,527 customers paying us more than $100,000, a 23% increase year over year. Revenue contribution from these large customers grew 32% year- over- year, and they now contribute 69% of revenue, up from 67% of revenue in the first quarter last year. We saw particular strength with our largest customers, those that spend over $1 million and $5 million with Cloudflare per year. Within both of these cohorts, we added a record number of customers, increasing 48% and 54% year over year, respectively, which shows the strong return on investment from our go-to-market improvements and large enterprise sales. Our dollar-based net retention was 111%, which is flat quarter to quarter. Our churn rates improved in the quarter.
We are seeing stabilization in our customers' businesses and reduced pricing pressure from competition. Our gross margin was 77.1%, again above our long-term target of 75%-77%. We delivered operating profit of $56 million, representing an operating margin of 11.7%, and we generated strong free cash flow of $52.9 million during the quarter. As we've talked about before, we have a unique view of the global economy based on the volume and diversity of data that flows through Cloudflare's network. In the past, that's given us an ability to make calls on the macro environment that turned out to be prescient. Given the nature of the uncertainty this time, we have less of a unique view into what lies ahead. But even without our privileged view, it's clear to everyone the world is a more volatile place today than it was even a quarter ago.
I'm incredibly proud of how our team has navigated this volatility. That starts on the cost side. We've been able to manage the continued expansion of our network without a significant change to our CapEx plan. We continue to invest behind actual demand to not get too far over our skis and have robust and diversified supply chains to mitigate tariff and trade risks. This is unique compared with some of our on-prem hardware competition, where we're seeing the last potential customer holdouts begin to migrate away from them because of the uncertainty tariffs will pose if your solution is a box that has to be shipped. On the revenue side, our investment in our go-to-market team remains early, but it's already paying off. This quarter, we achieved a number of milestones.
We landed the largest contract in Cloudflare's history, a milestone deal of more than $100 million driven by our Workers developer platform. We closed the longest duration contract in Cloudflare's history for Zero Trust. We delivered another double-digit year-over-year improvement in sales productivity. We saw quarter-over-quarter improvement in our sales cycles, even as we closed larger deals with more sophisticated buyers, and our new pipeline attainment was ahead of our forecast. What you see in these results is evidence of what we've been building toward: a company committed to disciplined execution regardless of external factors, a company becoming more mission-critical to our customers each day, and a company with growing strategic importance at the center of the internet. The short term may continue to be volatile in terms of external influences, but the long term remains as full of opportunities for Cloudflare as ever.