Subscribe to receive notifications of new posts:

Cloudflare is faster than Zscaler


15 min read

This post is also available in Français, 简体中文, 繁體中文, 日本語, 한국어, Deutsch and Español.

Cloudflare is faster than Zscaler

Every Innovation Week, Cloudflare looks at our network’s performance versus our competitors. In past weeks, we’ve focused on how much faster we are compared to reverse proxies like Akamai, or platforms that sell edge compute that compares to our Supercloud, like Fastly and AWS. For CIO Week, we want to show you how our network stacks up against competitors that offer forward proxy services. These products are part of our Zero Trust platform, which helps secure applications and Internet experiences out to the public Internet, as opposed to our reverse proxy which protects your websites from outside users.

We’ve run a series of tests comparing our Zero Trust services with Zscaler. We’ve compared our ZT Application protection product Cloudflare Access against Zscaler Private Access (ZPA). We’ve compared our Secure Web Gateway, Cloudflare Gateway, against Zscaler Internet Access (ZIA), and finally our Remote Browser Isolation product, Cloudflare Browser Isolation, against Zscaler Cloud Browser Isolation. We’ve found that Cloudflare Gateway is 58% faster than ZIA in our tests, Cloudflare Access is 38% faster than ZPA worldwide, and Cloudflare Browser Isolation is 45% faster than Zscaler Cloud Browser Isolation worldwide. For each of these tests, we used 95th percentile Time to First Byte and Response tests, which measure the time it takes for a user to make a request, and get the start of the response (Time to First Byte), and the end of the response (Response). These tests were designed with the goal of trying to measure performance from an end-user perspective.

In this blog we’re going to talk about why performance matters for each of these products, do a deep dive on what we’re measuring to show that we’re faster, and we’ll talk about how we measured performance for each product.

Why does performance matter?

Performance matters because it impacts your employees' experience and their ability to get their job done. Whether it’s accessing services through access control products, connecting out to the public Internet through a Secure Web Gateway, or securing risky external sites through Remote Browser Isolation, all of these experiences need to be frictionless.

Say Anna at Acme Corporation is connecting from Sydney out to Microsoft 365 or Teams to get some work done. If Acme’s Secure Web Gateway is located far away from Anna in Singapore, then Anna’s traffic may go out of Sydney to Singapore, and then back into Sydney to reach her email. If Acme Corporation is like many companies that require Anna to use Microsoft Outlook in online mode, her performance may be painfully slow as she waits for her emails to send and receive. Microsoft 365 recommends keeping latency as low as possible and bandwidth as high as possible. That extra hop Anna has to take through her gateway could decrease throughput and increase her latency, giving Anna a bad experience.

In another example, if Anna is connecting to a hosted, protected application like Jira to complete some tickets, she doesn’t want to be waiting constantly for pages to load or to authenticate her requests. In an access-controlled application, the first thing you do when you connect is you log in. If that login takes a long time, you may get distracted with a random message from a coworker or maybe will not want to tackle any of the work at all. And even when you get authenticated, you still want your normal application experience to be snappy and smooth: users should never notice Zero Trust when it’s at its best.

If these products or experiences are slow, then something worse might happen than your users complaining: they may find ways to turn off the products or bypass them, which puts your company at risk. A Zero Trust product suite is completely ineffective if no one is using it because it’s slow. Ensuring Zero Trust is fast is critical to the effectiveness of a Zero Trust solution: employees won’t want to turn it off and put themselves at risk if they barely know it’s there at all.

Services like Zscaler may outperform many older, antiquated solutions, but their network still fails to measure up to a highly performant, optimized network like Cloudflare’s. We’ve tested all of our Zero Trust products against Zscaler’s equivalents, and we’re going to show you that we’re faster. So let’s dig into the data and show you how and why we’re faster in three critical Zero Trust scenarios, starting with Secure Web Gateway: comparing Cloudflare Gateway to Zscaler Internet Access (ZIA).

Cloudflare Gateway: a performant secure web gateway at your doorstep

A secure web gateway needs to be fast because it acts as a funnel for all of an organization’s Internet-bound traffic. If a secure web gateway is slow, then any traffic from users out to the Internet will be slow. If traffic out to the Internet is slow, then users may be prompted to turn off the Gateway, putting the organization at risk of attack.

But in addition to being close to users, a performant web gateway needs to also be well-peered with the rest of the Internet to avoid slow paths out to websites users want to access. Remember that traffic through a secure web gateway follows a forward proxy path: users connect to the proxy, and the proxy connects to the websites users are trying to access. Therefore, it behooves the proxy to be well-connected to ensure that the user traffic can get where it needs to go as fast as possible.

When comparing secure web gateway products, we pitted the Cloudflare Gateway and WARP client against Zscaler Internet Access (ZIA), which performs the same functions. Fortunately for Cloudflare users, Gateway and Cloudflare’s network is not only embedded deep into last mile networks close to users, but is also one of the most well peered networks in the world. We use our most peered network to be 55% faster than ZIA for Gateway user scenarios. Below is a box plot showing the 95th percentile response time for Cloudflare, Zscaler, and a control set that didn’t use a gateway at all:

Secure Web Gateway - Response Time
95th percentile (ms)
Control 142.22
Cloudflare 163.77
Zscaler 365.77

This data shows that not only is Cloudflare much faster than Zscaler for Gateway scenarios, but that Cloudflare is actually more comparable to not using a secure web gateway at all rather than Zscaler.

To best measure the end-user Gateway experience, we are looking at 95th percentile response time from the end-user: we’re measuring how long it takes for a user to go through the proxy, have the proxy make a request to a website on the Internet, and finally return the response. This measurement is important because it’s an accurate representation of what users see.

When we measured against Zscaler, we had our end user client try to access five different websites: a website hosted in Azure, a Cloudflare-protected Worker, Google, Slack, and Zoom: websites that users would connect to on a regular basis. In each of those instances, Cloudflare outperformed Zscaler, and in the case of the Cloudflare-protected Worker, Gateway even outperformed the control for 95th percentile Response time. Here is a box plot showing the 95th percentile responses broken down by the different endpoints we queried as a part of our tests:

No matter where you go on the Internet, Cloudflare’s Gateway outperforms Zscaler Internet Access (ZIA) when you look at end-to-end response times. But why are we so much faster than Zscaler? The answer has to do with something that Zscaler calls proxy latency.

Proxy latency is the amount of time a user request spends on a Zscaler machine before being sent to its destination and back to the user. This number completely excludes the time it takes a user to reach Zscaler, and the time it takes Zscaler to reach the destination and restricts measurement to the milliseconds Zscaler spends processing requests.

Zscaler’s latency SLA says that 95% of your requests will spend less than 100 ms on a Zscaler device. Zscaler promises that the latency they can measure on their edge, not the end-to-end latency that actually matters, will be 100ms or less for 95% of user requests. You can even see those metrics in Zscaler’s Digital Experience to measure for yourself. If we can get this proxy latency from Zscaler logs and compare it to the Cloudflare equivalent, we can see how we stack up to Zscaler’s SLA metrics. While we don’t yet have those metrics exposed to customers, we were able to enable tracing on Cloudflare to measure the Cloudflare proxy latency.

The results show that at the 95th percentile, Zscaler was exceeding their SLA, and the Cloudflare proxy latency was 7ms. Furthermore, when our proxy latency was 100ms (meeting the Zscaler SLA), their proxy latencies were over 10x ours. Zscaler’s proxy latency accounts for the difference in performance we saw at the 95th percentile, being anywhere between 140-240 ms slower than Cloudflare for each of the sites. Here are the Zscaler proxy latency values at different percentiles for all sites tested, and then broken down by each site:

Zscaler Internet Access (ZIA) P90 Proxy Latency (ms) P95 Proxy Latency (ms) P99 Proxy Latency (ms) P99.9 Proxy Latency (ms) P99.957 Proxy Latency (ms)
Global 06.0 142.0 625.0 1,071.7 1,383.7
Azure Site 97.0 181.0 458.5 1,032.7 1,291.3
Zoom 206.0 254.2 659.8 1,297.8 1,455.4
Slack 118.8 186.2 454.5 1,358.1 1,625.8
Workers Site 97.8 184.1 468.3 1,246.2 1,288.6
Google 13.7 100.8 392.6 848.9 1,115.0

At the 95th percentile, not only were their proxy latencies out of SLA, those values show the difference between Zscaler and Cloudflare: taking Zoom as an example, if Zscaler didn’t have the proxy latency, they would be on-par with Cloudflare and the control. Cloudflare’s equivalent of proxy latency is so small that using us is just like using the public Internet:

Cloudflare Gateway P90 Proxy Latency (ms) P95 Proxy Latency (ms) P99 Proxy Latency (ms) P99.9 Proxy Latency (ms) P99.957 Proxy Latency (ms)
Global 5.6 7.2 15.6 32.2 101.9
Azure Site 6.2 7.7 12.3 18.1 19.2
Zoom 5.1 6.2 9.6 25.5 31.1
Slack 5.3 6.5 10.5 12.5 12.8
Workers Site 5.1 6.1 9.4 17.3 20.5
Google 5.3 7.4 12.0 26.9 30.2

The 99.957 percentile may seem strange to include, but it marks the percentile at which Cloudflare’s proxy latencies finally exceeded 100ms. Cloudflare’s 99.957 percentile proxy latency is even faster than Zscaler’s 90th percentile proxy latency. Even on the metric Zscaler cares about and holds themselves accountable for despite proxy latency not being the metric customers care about, Cloudflare is faster.

Getting this view of data was not easy. Existing testing frameworks like Catchpoint are unsuitable for this task because performance testing requires that you run the ZIA client or the WARP client on the testing endpoint. We also needed to make sure that the Cloudflare test and the Zscaler test are running on similar machines in the same place to measure performance as good as possible. This allows us to measure the end-to-end responses coming from the same location where both test environments are running:

In our setup, we put three VMs in the cloud side by side: one running Cloudflare WARP connecting to our Gateway, one running ZIA, and one running no proxy at all as a control. These VMs made requests every three minutes to the five different endpoints mentioned above and logged the HTTP browser timings for how long each request took. Based on this, we are able to get a user-facing view of performance that is meaningful.

A quick summary so far: Cloudflare is faster than Zscaler when we’re protecting users from the public Internet through a secure web gateway from an end-user perspective. Cloudflare is even faster than Zscaler according to Zscaler’s small definition of what performance through a secure web gateway means. But let’s take a look at scenarios where you need access for specific applications through Zero Trust access.

Cloudflare Access: the fastest Zero Trust proxy

Access control needs to be seamless and transparent to the user: the best compliment for a Zero Trust solution is employees barely notice it’s there. Services like Cloudflare Access and Zscaler Private Access (ZPA) allow users to cache authentication information on the provider network, ensuring applications can be accessed securely and quickly to give users that seamless experience they want. So having a network that minimizes the number of logins required while also reducing the latency of your application requests will help keep your Internet experience snappy and reactive.

Cloudflare Access does all that 38% faster than Zscaler Private Access (ZPA), ensuring that no matter where you are in the world, you’ll get a fast, secure application experience:

ZT Access - Time to First Byte (Global)
95th Percentile (ms)
Cloudflare 849
Zscaler 1,361

When we drill into the data, we see that Cloudflare is consistently faster everywhere around the world. For example, take Tokyo, where Cloudflare’s 95th percentile time to first byte times are 22% faster than Zscaler:

When we evaluate Cloudflare against Zscaler for application access scenarios, we are looking at two distinct scenarios that need to be measured individually. The first scenario is when a user logs into their application and has to authenticate. In this case, the Zero Trust Access service will direct the user to a login page, the user will authenticate, and then be redirected to their application.

This is called a new session, because no authentication information is cached or exists on the Access network. The second scenario is called an existing session, when a user has already been authenticated and that authentication information can be cached. This scenario is usually much faster, because it doesn’t require an extra call to an identity provider to complete.

We like to measure these scenarios separately, because when we look at 95th percentile values, we would almost always be looking at new sessions if we combined new and existing sessions together. But across both scenarios, Cloudflare is consistently faster in every region. Here’s how this data looks when you take a location Zscaler is more likely to have good peering in: users in Chicago, IL connecting to an application hosted in US-Central.

ZT Access - 95th Percentile Time to First Byte
New Sessions (ms) Existing Sessions (ms)
Cloudflare 1,032 293
Zscaler 1,373 338

Cloudflare is faster overall there as well. Here’s a histogram of 95th percentile response times for new connections overall:

You’ll see that Cloudflare’s network really gives a performance boost on login, helping find optimal paths back to authentication providers to retrieve login details. In this test, Cloudflare never takes more than 2.5 seconds to return a login response, but half of Zscaler’s 95th percentile responses are almost double that, at around four seconds. This would suggest that Zscaler’s network isn’t peered as well, which causes latency early on. But it may also suggest that Zscaler may do better when the connection is established and everything is cached. But on an existing connection, Cloudflare still comes out ahead:

Zscaler and Cloudflare do match up more evenly at lower latency buckets, but Cloudflare’s response times are much more consistent, and you can see that Zscaler has half of their responses which take almost a second to load. This further highlights how well-connected we are: because we’re in more places, we provide a better application experience, and we don’t have as many edge cases with high latency and poor application performance.

We like to separate these new and existing sessions because it’s important to look at similar request paths to do a proper comparison. For example, if we’re comparing a request via Zscaler on an existing session and a request via  Cloudflare on a new session, we could see that Cloudflare was much slower than Zscaler because of the need to authenticate. So when we contracted a third party to design these tests, we made sure that they took that into account.

For these tests, Cloudflare contracted Miercom, a third party who performed a set of tests that was intended to replicate an end-user connecting to a resource protected by Cloudflare or Zscaler. Miercom set up application instances in 14 locations around the world, and devised a test that would log into the application through various Zero Trust providers to access certain content. The test methodology is described as follows, but you can look at the full report from Miercom detailing their test methodology here:

  • User connects to the application from a browser mimicked by a Catchpoint instance - new session
  • User authenticates against their identity provider
  • User accesses resource
  • User refreshes the browser page and tries to access the same resource but with credentials already present - existing session

This allows us to look at Cloudflare versus Zscaler for application performance for both new and existing sessions, and we’ve shown that we’re faster. We’re faster in secure web gateway scenarios too.

Both secure web gateway and Zero Trust access scenarios can be further secured using remote browser isolation. RBI offers a clientless method of both securing access to data within an application and threat defense when browsing resources on the public Internet.

Cloudflare Browser Isolation: your friendly neighborhood web browser

Remote browser isolation products have a very strong dependency on the public Internet: if your connection to your browser isolation product isn’t good, then your browser experience will feel weird and slow. Remote browser isolation is extraordinarily dependent on performance to feel smooth and seamless to the users: if everything is fast as it should be, then users shouldn’t even notice that they’re using browser isolation. For this test, we’re pitting Cloudflare Browser Isolation against Zscaler Cloud Browser Isolation.

Cloudflare once again is faster than Zscaler for remote browser isolation performance. Comparing 95th percentile time to first byte, Cloudflare is 45% faster than Zscaler across all regions:

ZT RBI - Time to First Byte (Global)
95th Percentile (ms)
Cloudflare 2,072
Zscaler 3,781

When you compare the total response time or the ability for a browser isolation product to deliver a full response back to a user, Cloudflare is still 39% faster than Zscaler:

ZT RBI - Time to First Byte (Global)
95th Percentile (ms)
Cloudflare 2,394
Zscaler 3,932

Cloudflare’s network really shines here to help deliver the best user experience to our customers. Because Cloudflare’s network is incredibly well-peered close to end-user devices, we are able to drive down our time to first byte and response times, helping improve the end-user experience.

To measure this, we went back to Miercom to help get us the data we needed by having Catchpoint nodes connect to Cloudflare Browser Isolation and Zscaler Cloud Browser Isolation across the world from the same 14 locations and had devices simulating clients try to reach applications through the browser isolation products in each locale. For more on the test methodology, you can refer to that same Miercom report, linked here.

Next-generation performance in a Zero Trust world

In a non-Zero Trust world, you and your IT teams were the network operator — which gave you the ability to control performance. While this control was comforting, it was also a huge burden on your IT teams who had to manage middle mile connections between offices and resources. But in a Zero Trust world, your network is now… well, it’s the public Internet. This means less work for your teams — but a lot more responsibility on your Zero Trust provider, which has to manage performance for every single one of your users. The better your Zero Trust provider is at improving end-to-end performance, the better an experience your users will have and the less risk you expose yourself to. For real-time applications like authentication and secure web gateways, having a snappy user experience is critical.

A Zero Trust provider needs to not only secure your users on the public Internet, but it also needs to optimize the public Internet to make sure that your users continuously stay protected. Moving to Zero Trust doesn’t just reduce the need for corporate networks, it also allows user traffic to flow to resources more naturally. However, given your Zero Trust provider is going to be the gatekeeper for all your users and all your applications, performance is a critical aspect to evaluate to reduce friction for your users and reduce the likelihood that users will complain, be less productive, or turn the solutions off. Cloudflare is constantly improving our network to ensure that users always have the best experience, and this comes not just from routing fixes, but also through expanding peering arrangements and adding new locations. It’s this tireless effort that makes us the fastest Zero Trust provider.

Check out our compare page for more detail on how Cloudflare’s network architecture stacks up against Zscaler.

We protect entire corporate networks, help customers build Internet-scale applications efficiently, accelerate any website or Internet application, ward off DDoS attacks, keep hackers at bay, and can help you on your journey to Zero Trust.

Visit from any device to get started with our free app that makes your Internet faster and safer.

To learn more about our mission to help build a better Internet, start here. If you're looking for a new career direction, check out our open positions.
CIO WeekSpeedZero Trust

Follow on X

David Tuber|@tubes__

Related posts