On June 12, 2025, Cloudflare suffered a significant service outage that affected a large set of our critical services. As explained in our blog post about the incident, the cause was a failure in the underlying storage infrastructure used by our Workers KV service. Workers KV is not only relied upon by many customers, but serves as critical infrastructure for many other Cloudflare products, handling configuration, authentication and asset delivery across the affected services. Part of this infrastructure was backed by a third-party cloud provider, which experienced an outage on June 12 and directly impacted availability of our KV service.
Today we're providing an update on the improvements that have been made to Workers KV to ensure that a similar outage cannot happen again. We are now storing all data on our own infrastructure. We are also serving all requests from our own infrastructure in addition to any third-party cloud providers used for redundancy, ensuring high availability and eliminating single points of failure. Finally, the work has meaningfully improved performance and set a clear path for the removal of any reliance on third-party providers as redundant back-ups.
Workers KV is a global key-value store that Continue reading
OpenAI has just announced their latest open-weight models — and we are excited to share that we are working with them as a Day 0 launch partner to make these models available in Cloudflare's Workers AI. Cloudflare developers can now access OpenAI's first open model, leveraging these powerful new capabilities on our platform. The new models are available starting today at @cf/openai/gpt-oss-120b and @cf/openai/gpt-oss-20b.
Workers AI has always been a champion for open models and we’re thrilled to bring OpenAI's new open models to our platform today. Developers who want transparency, customizability, and deployment flexibility can rely on Workers AI as a place to deliver AI services. Enterprises that need the ability to run open models to ensure complete data security and privacy can also deploy with Workers AI. We are excited to join OpenAI in fulfilling their mission of making the benefits of AI broadly accessible to builders of any size.
The OpenAI models have been released in two sizes: a 120 billion parameter model and a 20 billion parameter model. Both of them are Mixture-of-Experts models – a popular architecture for recent model releases – that allow relevant experts to be called for a Continue reading
One of Cloudflare’s big focus areas is making the Internet faster for end users. Part of the way we do that is by looking at the "big rocks" or bottlenecks that might be slowing things down — particularly processes on the critical path. When we recently turned our attention to our privacy proxy product, we found a big opportunity for improvement.
What is our privacy proxy product? These proxies let users browse the web without exposing their personal information to the websites they’re visiting. Cloudflare runs infrastructure for privacy proxies like Apple’s Private Relay and Microsoft’s Edge Secure Network.
Like any secure infrastructure, we make sure that users authenticate to these privacy proxies before we open up a connection to the website they’re visiting. In order to do this in a privacy-preserving way (so that Cloudflare collects the least possible information about end-users) we use an open Internet standard – Privacy Pass – to issue tokens that authenticate to our proxy service.
Every time a user visits a website via our Privacy Proxy, we check the validity of the Privacy Pass token which is included in the Proxy-Authorization header in their request. Before we cryptographically validate a user's token, we check Continue reading
We are observing stealth crawling behavior from Perplexity, an AI-powered answer engine. Although Perplexity initially crawls from their declared user agent, when they are presented with a network block, they appear to obscure their crawling identity in an attempt to circumvent the website’s preferences. We see continued evidence that Perplexity is repeatedly modifying their user agent and changing their source ASNs to hide their crawling activity, as well as ignoring — or sometimes failing to even fetch — robots.txt files.
The Internet as we have known it for the past three decades is rapidly changing, but one thing remains constant: it is built on trust. There are clear preferences that crawlers should be transparent, serve a clear purpose, perform a specific activity, and, most importantly, follow website directives and preferences. Based on Perplexity’s observed behavior, which is incompatible with those preferences, we have de-listed them as a verified bot and added heuristics to our managed rules that block this stealth crawling.
We received complaints from customers who had both disallowed Perplexity crawling activity in their robots.txt files and also created WAF rules to specifically block both of Perplexity’s declared crawlers: PerplexityBot and Perplexity-User. Continue reading
Earlier this year, a group of external researchers identified and reported a vulnerability in Cloudflare’s SSL for SaaS v1 (Managed CNAME) product offering through Cloudflare’s bug bounty program. We officially deprecated SSL for SaaS v1 in 2021; however, some customers received extensions for extenuating circumstances that prevented them from migrating to SSL for SaaS v2 (Cloudflare for SaaS). We have continually worked with the remaining customers to migrate them onto Cloudflare for SaaS over the past four years and have successfully migrated the vast majority of these customers. For most of our customers, there is no action required; for the very small number of SaaS v1 customers, we will be actively working to help migrate you to SSL for SaaS v2 (Cloudflare for SaaS).
Back in 2017, Cloudflare announced SSL for SaaS, a product that allows SaaS providers to extend the benefits of Cloudflare security and performance to their end customers. Using a “Managed CNAME” configuration, providers could bring their customer’s domain onto Cloudflare. In the first version of SSL for SaaS (v1), the traffic for Custom Hostnames is proxied to the origin based on the IP addresses assigned to the Continue reading
On July 23, 2025, the White House unveiled its AI Action Plan (Plan), a significant policy document outlining the current administration's priorities and deliverables in Artificial Intelligence. This plan emerged after the White House received over 10,000 public comments in response to a February 2025 Request for Information (RFI). Cloudflare’s comments urged the White House to foster conditions for U.S. leadership in AI and support open-source AI, among other recommendations.
There is a lot packed into the three pillar, 28-page Plan.
Pillar I: Accelerate AI Innovation. Focuses on removing regulations, enabling AI adoption and developing, and ensuring the availability of open-source and open-weight AI models.
Pillar II: Build American AI Infrastructure. Prioritizes the construction of high-security data centers, bolstering critical infrastructure cybersecurity, and promoting Secure-by-Design AI technologies.
Pillar III: Lead in International AI Diplomacy and Security. Centers on providing America’s allies and partners with access to AI, as well as strengthening AI compute export control enforcement.
Each of these pillars outlines policy recommendations for various federal agencies to advance the plan’s overarching goals. There’s much that the Plan gets right. Below we cover a few parts of the Plan that we think are particularly important. Continue reading
Social media users are tired of losing their identity and data every time a platform shuts down or pivots. In the ATProto ecosystem — short for Authenticated Transfer Protocol — users own their data and identities. Everything they publish becomes part of a global, cryptographically signed shared social web. Bluesky is the first big example, but a new wave of decentralized social networks is just beginning. In this post I’ll show you how to get started, by building and deploying a fully serverless ATProto application on Cloudflare’s Developer Platform.
Why serverless? The overhead of managing VMs, scaling databases, maintaining CI pipelines, distributing data across availability zones, and securing APIs against DDoS attacks pulls focus away from actually building.
That’s where Cloudflare comes in. You can take advantage of our Developer Platform to build applications that run on our global network: Workers deploy code globally in milliseconds, KV provides fast, globally distributed caching, D1 offers a distributed relational database, and Durable Objects manage WebSockets and handle real-time coordination. Best of all, everything you need to build your serverless ATProto application is available on our free tier, so you can get started without spending a cent. You can find the code in Continue reading
The Cloudflare Business Intelligence team manages a petabyte-scale data lake and ingests thousands of tables every day from many different sources. These include internal databases such as Postgres and ClickHouse, as well as external SaaS applications such as Salesforce. These tasks are often complex and tables may have hundreds of millions or billions of rows of new data each day. They are also business-critical for product decisions, growth plannings, and internal monitoring. In total, about 141 billion rows are ingested every day.
As Cloudflare has grown, the data has become ever larger and more complex. Our existing Extract Load Transform (ELT) solution could no longer meet our technical and business requirements. After evaluating other common ELT solutions, we concluded that their performance generally did not surpass our current system, either.
It became clear that we needed to build our own framework to cope with our unique requirements — and so Jetflow was born.
Over 100x efficiency improvement in GB-s:
Our longest running job with 19 billion rows was taking 48 hours using 300 GB of memory, and now completes in 5.5 hours using 4 GB of memory
We estimate that ingestion of Continue reading
On July 19, 2025, Microsoft disclosed CVE-2025-53770, a critical zero-day Remote Code Execution (RCE) vulnerability. Assigned a CVSS 3.1 base score of 9.8 (Critical), the vulnerability affects SharePoint Server 2016, 2019, and the Subscription Edition, along with unsupported 2010 and 2013 versions. Cloudflare’s WAF Managed Rules now includes 2 emergency releases that mitigate these vulnerabilities for WAF customers.
The vulnerability's root cause is improper deserialization of untrusted data, which allows a remote, unauthenticated attacker to execute arbitrary code over the network without any user interaction. Moreover, what makes CVE-2025-53770 uniquely threatening is its methodology – the exploit chain, labeled "ToolShell." ToolShell is engineered to play the long-game: attackers are not only gaining temporary access, but also taking the server's cryptographic machine keys, specifically the ValidationKey and DecryptionKey. Possessing these keys allows threat actors to independently forge authentication tokens and __VIEWSTATE payloads, granting them persistent access that can survive standard mitigation strategies such as a server reboot or removing web shells.
In response to the active nature of these attacks, the U.S. Cybersecurity and Infrastructure Security Agency (CISA) added CVE-2025-53770 to its Known Exploited Vulnerabilities (KEV) catalog with an emergency remediation deadline. Continue reading
Cloudflare’s network currently spans more than 330 cities in over 125 countries, and we interconnect with over 13,000 network providers in order to provide a broad range of services to millions of customers. The breadth of both our network and our customer base provides us with a unique perspective on Internet resilience, enabling us to observe the impact of Internet disruptions at both a local and national level, as well as at a network level.
As we have noted in the past, this post is intended as a summary overview of observed and confirmed disruptions, and is not an exhaustive or complete list of issues that have occurred during the quarter. A larger list of detected traffic anomalies is available in the Cloudflare Radar Outage Center. Note that both bytes-based and request-based traffic graphs are used within the post to illustrate the impact of the observed disruptions — the choice of metric was generally made based on which better illustrated the impact of the disruption.
In our Q1 2025 summary post, we noted that we had not observed any government-directed Internet shutdowns during the quarter. Unfortunately, that forward progress was short-lived — in the second quarter of 2025, we Continue reading
Cloudflare has servers in 330 cities spread across 125+ countries. All of these servers run Quicksilver, which is a key-value database that contains important configuration information for many of our services, and is queried for all requests that hit the Cloudflare network.
Because it is used while handling requests, Quicksilver is designed to be very fast; it currently responds to 90% of requests in less than 1 ms and 99.9% of requests in less than 7 ms. Most requests are only for a few keys, but some are for hundreds or even more keys.
Quicksilver currently contains over five billion key-value pairs with a combined size of 1.6 TB, and it serves over three billion keys per second, worldwide. Keeping Quicksilver fast provides some unique challenges, given that our dataset is always growing, and new use cases are added regularly.
Quicksilver used to store all key-values on all servers everywhere, but there is obviously a limit to how much disk space can be used on every single server. For instance, the more disk space used by Quicksilver, the less disk space is left for content caching. Also, with each added server that contains a particular Continue reading
Many developers, data scientists, and researchers do much of their work in Python notebooks: they’ve been the de facto standard for data science and sharing for well over a decade. Notebooks are popular because they make it easy to code, explore data, prototype ideas, and share results. We use them heavily at Cloudflare, and we’re seeing more and more developers use notebooks to work with data – from analyzing trends in HTTP traffic, querying Workers Analytics Engine through to querying their own Iceberg tables stored in R2.
Traditional notebooks are incredibly powerful — but they were not built with collaboration, reproducibility, or deployment as data apps in mind. As usage grows across teams and workflows, these limitations face the reality of work at scale.
marimo reimagines the notebook experience with these challenges in mind. It’s an open-source reactive Python notebook that’s built to be reproducible, easy to track in Git, executable as a standalone script, and deployable. We have partnered with the marimo team to bring this streamlined, production-friendly experience to Cloudflare developers. Spend less time wrestling with tools and more time exploring your data.
Today, we’re excited to announce three things:
On 14 July 2025, Cloudflare made a change to our service topologies that caused an outage for 1.1.1.1 on the edge, resulting in downtime for 62 minutes for customers using the 1.1.1.1 public DNS Resolver as well as intermittent degradation of service for Gateway DNS.
Cloudflare's 1.1.1.1 Resolver service became unavailable to the Internet starting at 21:52 UTC and ending at 22:54 UTC. The majority of 1.1.1.1 users globally were affected. For many users, not being able to resolve names using the 1.1.1.1 Resolver meant that basically all Internet services were unavailable. This outage can be observed on Cloudflare Radar.
The outage occurred because of a misconfiguration of legacy systems used to maintain the infrastructure that advertises Cloudflare’s IP addresses to the Internet.
This was a global outage. During the outage, Cloudflare's 1.1.1.1 Resolver was unavailable worldwide.
We’re very sorry for this outage. The root cause was an internal configuration error and not the result of an attack or a BGP hijack. In this blog, we’re going to talk about what the failure was, why it occurred, and what we’re doing to Continue reading
We are thrilled to announce that Cloudflare has been named a Visionary in the 2025 Gartner® Magic Quadrant™ for Secure Access Service Edge (SASE) Platforms1 report. We view this evaluation as a significant recognition of our strategy to help connect and secure workspace security and coffee shop networking through our unique connectivity cloud approach. You can read more about our position in the report here.
Since launching Cloudflare One, our SASE platform, we have delivered hundreds of features and capabilities from our lightweight branch connector and intuitive native Data Loss Prevention (DLP) service to our new secure infrastructure access tools. By operating the world’s most powerful, programmable network we’ve built an incredible foundation to deliver a comprehensive SASE platform.
Today, we operate the world's most expansive SASE network in order to deliver connectivity and security close to where users and applications are, anywhere in the world. We’ve developed our services from the ground up to be fully integrated and run on every server across our network, delivering a unified experience to our customers. And we enable these services with a unified control plane, enabling end-to-end visibility and control anywhere in the world. Tens of thousands of customers Continue reading
Welcome to the 22nd edition of the Cloudflare DDoS Threat Report. Published quarterly, this report offers a comprehensive analysis of the evolving threat landscape of Distributed Denial of Service (DDoS) attacks based on data from the Cloudflare network. In this edition, we focus on the second quarter of 2025. To view previous reports, visit www.ddosreport.com.
June was the busiest month for DDoS attacks in 2025 Q2, accounting for nearly 38% of all observed activity. One notable target was an independent Eastern European news outlet protected by Cloudflare, which reported being attacked following its coverage of a local Pride parade during LGBTQ Pride Month.
DDoS attacks continue to break records. During 2025 Q2, Cloudflare automatically blocked the largest ever reported DDoS attacks, peaking at 7.3 terabits per second (Tbps) and 4.8 billion packets per second (Bpps).
Overall, in 2025 Q2, hyper-volumetric DDoS attacks skyrocketed. Cloudflare blocked over 6,500 hyper-volumetric DDoS attacks, an average of 71 per day.
Although the overall number of DDoS attacks dropped compared to the previous quarter — which saw an unprecedented surge driven by a large-scale campaign targeting Cloudflare’s network and critical Internet infrastructure protected by Cloudflare — the Continue reading
Quicksilver is a key-value store developed internally by Cloudflare to enable fast global replication and low-latency access on a planet scale. It was initially designed to be a global distribution system for configurations, but over time it gained popularity and became the foundational storage system for many products in Cloudflare.
A previous post described how we moved Quicksilver to production and started replicating on all machines across our global network. That is what we called Quicksilver v1: each server has a full copy of the data and updates it through asynchronous replication. The design served us well for some time. However, as our business grew with an ever-expanding data center footprint and a growing dataset, it became more and more expensive to store everything everywhere.
We realized that storing the full dataset on every server is inefficient. Due to the uniform design, data accessed in one region or data center is replicated globally, even if it's never accessed elsewhere. This leads to wasted disk space. We decided to introduce a more efficient system with two new server roles: replica, which stores the full dataset and proxy, which acts as a persistent cache, evicting unused key-value pairs to free Continue reading
At Cloudflare, PostgreSQL and ClickHouse are our standard databases for transactional and analytical workloads. If you’re part of a team building products with configuration in our Dashboard, chances are you're using PostgreSQL. It’s fast, versatile, reliable, and backed by over 30 years of development and real-world use. It has been a foundational part of our infrastructure since the beginning, and today we run hundreds of PostgreSQL instances across a wide range of configurations and replication setups.
ClickHouse is a more recent addition to our stack. We started using it around 2017, and it has enabled us to ingest tens of millions of rows per second while supporting millisecond-level query performance. ClickHouse is a remarkable technology, but like all systems, it involves trade-offs.
In this post, I’ll explain why we chose TimescaleDB — a Postgres extension — over ClickHouse to build the analytics and reporting capabilities in our Zero Trust product suite.
After a decade in software development, I’ve grown to appreciate systems that are simple and boring. Over time, I’ve found myself consistently advocating for architectures with the fewest moving parts possible. Whenever I see a system diagram with more than three boxes, I ask: Why Continue reading
Cloudflare’s SASE platform is on a mission to strengthen our platform-wide support for hostname- and domain-based policies. This mission is being driven by enthusiastic demands from our customers, and boosted along the way by several interesting engineering challenges. Today, we’re taking a deep dive into the first milestone of this mission, which we recently released in open beta: egress policies by hostname, domain, content category, and application. Let’s dive right in!
Customers use our egress policies to control how their organization's Internet traffic connects to external services. An egress policy allows a customer to control the source IP address their traffic uses, as well as the geographic location that their traffic uses to egress onto the public Internet. Control of the source IP address is especially useful when accessing external services that apply policies to traffic based on source IPs, using IP Access Control Lists (ACLs). Some services use IP ACLs because they improve security, while others use them because they are explicitly required by regulation or compliance frameworks.
(That said, it's important to clarify that we do not recommend relying on IP ACLs as the only security mechanism used to gate Continue reading
Almost 30 years ago, two graduate students at Stanford University — Larry Page and Sergey Brin — began working on a research project they called Backrub. That, of course, was the project that resulted in Google. But also something more: it created the business model for the web.
The deal that Google made with content creators was simple: let us copy your content for search, and we'll send you traffic. You, as a content creator, could then derive value from that traffic in one of three ways: running ads against it, selling subscriptions for it, or just getting the pleasure of knowing that someone was consuming your stuff.
Google facilitated all of this. Search generated traffic. They acquired DoubleClick and built AdSense to help content creators serve ads. And acquired Urchin to launch Google Analytics to let you measure just who was viewing your content at any given moment in time.
For nearly thirty years, that relationship was what defined the web and allowed it to flourish.
But that relationship is changing. For the first time in its history, the number of searches run on Google is declining. What's taking its place? AI.
If you're like me, you've been amazed Continue reading
As a site owner, how do you know which bots to allow on your site, and which you’d like to block? Existing identification methods rely on a combination of IP address range (which may be shared by other services, or change over time) and user-agent header (easily spoofable). These have limitations and deficiencies. In our last blog post, we proposed using HTTP Message Signatures: a way for developers of bots, agents, and crawlers to clearly identify themselves by cryptographically signing requests originating from their service.
Since we published the blog post on Message Signatures and the IETF draft for Web Bot Auth in May 2025, we’ve seen significant interest around implementing and deploying Message Signatures at scale. It’s clear that well-intentioned bot owners want a clear way to identify their bots to site owners, and site owners want a clear way to identify and manage bot traffic. Both parties seem to agree that deploying cryptography for the purposes of authentication is the right solution.
Today, we’re announcing that we’re integrating HTTP Message Signatures directly into our Verified Bots Program. This announcement has two main parts: (1) for bots, crawlers, and agents, we’re simplifying enrollment into the Verified Continue reading