Tom Leighton
Chief Executive Officer and Co-Founder at Akamai Technologies
Thanks, Tom, and thank you all for joining us today. Today is a very exciting day for Akamai. This afternoon, we announced that we've signed a definitive agreement to acquire Linode. We see this as a tremendous opportunity for Akamai and we believe that it will be transformational, as we expand our business into adjacent markets, become even more strategic for our customers and accelerate our growth and evolution as a company. We'll talk more about the note in a few minutes, but first I'd like to review some of the highlights from a very strong Q4 in 2021.
Turning to Slide 5. Q4 revenue was $905 million, up 7% year-over-year. Our revenue growth was driven by the continued strong demand for our security products as well as our fast-growing Edge Applications business. Non-GAAP operating margin in Q4 was 31%, up one point over Q4 in 2020. Q4 non-GAAP EPS was $1.49 per diluted share, up 12% year-over-year. For the full-year, revenue was $3.46 billion, up 8% over 2020. We expanded non-GAAP operating margin to 32% last year and we achieved this result while investing for future growth. Non-GAAP EPS last year was $5.74, up 10% over 2020.
2021 was also a very strong year for cash generation at Akamai. We generated $859 million in free cash flow last year, an increase of 78% over 2020. I think it's important to note that our excellent cash generation has allowed us to make strategic acquisitions like Guardicore in Q4 and now Linode to fuel our future growth, while also returning capital to shareholders. In Q4, we spent $271 million to buyback just over 2.4 million shares of stock. Over the course of the full year, we spent $522 million to buyback approximately 4.7 million shares.
Our primary use of cash is for M&A and offsetting the dilution from our equity compensation programs. Over the past 10 years, Akamai has also engaged an opportunistic buybacks that have resulted in a reduction of our fully diluted share count by about 12%. Last quarter, Security products continued their rapid growth, generating revenue of $365 million, up 23% year-over-year. For the full year, Security revenue reached $1.33 billion and grew 26% over 2020. Security represented 39% of our revenue last year, up from 33% in 2020. In recent years, Akamai has built one of the world's leading cloud security businesses. Our security solutions are highly differentiated and recognized as best-in-class by our customers.
We rely on Akamai to protect our most important digital assets from very determined and highly capable attackers. Results in Q4 were especially strong for our Bot Manager solution, which helps to defend against a wide range of automated attacks. Our new account protector solution, which provides account takeover protection also performed very well in Q4 in only a second quarter of availability. Our Web App Firewall offerings also posted excellent results in Q4, and Akamai was recognized as a leader in Gartner's 2021 Magic Quadrant for Web Application and API Protections, scoring the highest of 11 vendors and ability to execute.
In October, we acquired Guardicore to extend our Zero Trust solutions to help stop the spread of ransomware. As a part of Akamai, Guardicore has continued its strong growth momentum and closed major deals last quarter and one of the largest freight railways in the U.S., and at one of the largest telecommunication companies in South America. We're very excited about the value that Guardicore's micro-segmentation capabilities bring to our customers. And as Ed will talk about shortly, we now believe the Guardicore will drive significantly more revenue this year than we had initially forecast when we announced the transaction last fall.
Our CDN business generated revenue of $541 million in Q4, down 2% from Q4 in 2020. Traffic on our platform continue to be strong in Q4, peaking it over 200 terabits per second. Our Edge Application solutions had a great Q4, exiting the year with an annualized revenue run rate of more than $200 million and growing 30% for the full year. Our Akamai Edge Worker solution was adopted by a top sporting equipment company, a global Business Travel Service and one of the largest banks in the U.S. Overall, we're very pleased with our performance last year on both the top and bottom lines. We achieved our goals in 2021 and then some and I want to thank our employees for delivering such strong results as they continue to cope with the challenges of the pandemic.
I'll now move on to Slide 6. As many of you know, Akamai's mission is to power and protect life online, and our purpose in doing that is to make life better for billions of people, billions of times a day. Akamai has been doing this for more than 20 years. Enabled in part by a series of market to finding innovations, starting with the invention of content delivery networks in the late 1990s. As you can see on the next Slide #7, we follow this breakthrough in Internet technology with fundamental advances and video streaming, application acceleration, and web security. In each of these areas, Akamai was a major pioneer in enabling new capabilities. And in each of these areas, we're still the market leader today by far. Throughout the past 20 years, we've also been a pioneer and a leader in edge computing, beginning with the invention of edge site includes in the early 2000s, a technology that still used by thousands of our customers today.
And now turning to Slide 8. We're taking the next major step in our evolution by creating the world's most distributed compute platform, from cloud to edge, making it easier for developers and businesses to build, run and secure their applications online. As you can see in this afternoon's press release, we've entered into a definitive agreement to acquire Linode, the privately held company that makes cloud computing simple, affordable and accessible. Linode is known for its developer friendly services, the quality of their support and as a trusted infrastructure-as-a-service platform provider.
By combining Linode's developer-centric cloud advantages with Akamai's deep enterprise strengths, we believe that we can provide tremendous value to developers and enterprises as they build cloud applications on Akamai. We see plenty of opportunity for a differentiated offering among customers, who desire ease of use, wider reach beyond just a few parts, lower latency, stronger security and greater resiliency, all from a single platform and all at an affordable price point. Akamai's highly distributed edge platform as the global reach to enable any cloud application to deliver the best end-user experience anywhere that users or services consume apps. From the cloud to the edge, where more compute services will there as 5G and IoT take hold and expand.
The Akamai platform is uniquely suited for workloads that require high throughput, low latency and instant scalability on demand. Akamai has been perfecting this capability for many years and it's very hard to do. Akamai also has the capabilities needed to integrate seamlessly with both DIY Cloud apps, and third party cloud vendors as part of the larger cloud ecosystem. We believe that this flexibility will appeal to enterprises that want multi-vendor cloud strategy. To mitigate their vendor concentration risk and to ensure resiliency and seamless availability in case one vendor service experiences an outage and with Akamai's category-leading security solutions customers will be able to secure their apps from their point of origin to the edge.
All under Akamai's protective umbrella. Security delivered at the Edge offers unique advantages since it enables customers to manage security policies across all their apps and infrastructure, wherever they are located. We believe that such an end to end security approach will appeal to customers who want increased efficiency and greater resiliency along with lower security risk. The net of all this is that we believe that Akamai and Linode can solve customers' needs in ways that are not addressed in the market today. Forming a powerful winning combination that will enable customers to build, deliver and secure their apps on the platform that powers and protects life online.
Moving to slide 9 we see the acquisition of Linode as a transformational opportunity for Akamai. This slide shows the way that we presented our business at our Investor Day last year. With Linode Akamai will expand beyond security and delivery, into the world's most distributed cloud services provider with leading solutions for security, delivery and compute as shown here on slide 10. We will offer customers a breadth and depth of services uncommon in the cloud space today. A massive content delivery platform, the best application performance, easily use cloud and edge compute and category-leading security solutions. All backed by expert services and support professionals to help power and protect life online.
Given that we're announcing this acquisition at the same time as our earnings. I thought it would be helpful to have Adam Karon join us on the call today to talk more about Linode. Adam is our COO and he is responsible for running our compute and delivery businesses. Later this year, we'll also plan to hold an Investor Day when you'll be able to hear from Mani Sundaram, who leads our security business as well as from other Akamai executives. After Adam speaks Ed will cover the financial aspects of the acquisition and provide our outlook for 2022. Adam?
