Eliminating Cold Starts 2: shard and conquer

Five years ago, we announced that we were Eliminating Cold Starts with Cloudflare Workers. In that episode, we introduced a technique to pre-warm Workers during the TLS handshake of their first request. That technique takes advantage of the fact that the TLS Server Name Indication (SNI) is sent in the very first message of the TLS handshake. Armed with that SNI, we often have enough information to pre-warm the request’s target Worker.

Eliminating cold starts by pre-warming Workers during TLS handshakes was a huge step forward for us, but “eliminate” is a strong word. Back then, Workers were still relatively small, and had cold starts constrained by limits explained later in this post. We’ve relaxed those limits, and users routinely deploy complex applications on Workers, often replacing origin servers. Simultaneously, TLS handshakes haven’t gotten any slower. In fact, TLS 1.3 only requires a single round trip for a handshake – compared to three round trips for TLS 1.2 – and is more widely used than it was in 2021.

Earlier this month, we finished deploying a new technique intended to keep pushing the boundary on cold start reduction. The new technique (or old, depending on your perspective) uses Continue reading

Code Mode: the better way to use MCP

It turns out we've all been using MCP wrong.

Most agents today use MCP by directly exposing the "tools" to the LLM.

We tried something different: Convert the MCP tools into a TypeScript API, and then ask an LLM to write code that calls that API.

The results are striking:

1. We found agents are able to handle many more tools, and more complex tools, when those tools are presented as a TypeScript API rather than directly. Perhaps this is because LLMs have an enormous amount of real-world TypeScript in their training set, but only a small set of contrived examples of tool calls.

2. The approach really shines when an agent needs to string together multiple calls. With the traditional approach, the output of each tool call must feed into the LLM's neural network, just to be copied over to the inputs of the next call, wasting time, energy, and tokens. When the LLM can write code, it can skip all that, and only read back the final results it needs.

In short, LLMs are better at writing code to call MCP, than at calling MCP directly.

For those that aren't familiar: Model Context Protocol is a standard protocol Continue reading

Introducing new regional Internet traffic and Certificate Transparency insights on Cloudflare Radar

Since launching during Birthday Week in 2020, Radar has announced significant new capabilities and data sets during subsequent Birthday Weeks. We continue that tradition this year with a two-part launch, adding more dimensions to Radar’s ability to slice and dice the Internet.

First, we’re adding regional traffic insights. Regional traffic insights bring a more localized perspective to the traffic trends shown on Radar.

Second, we’re adding detailed Certificate Transparency (CT) data, too. The new CT data builds on the work that Cloudflare has been doing around CT since 2018, including Merkle Town, our initial CT dashboard.

Both features extend Radar's mission of providing deeper, more granular visibility into the health and security of the Internet. Below, we dig into these new capabilities and data sets.

Cloudflare Radar initially launched with visibility into Internet traffic trends at a national level: want to see how that Internet shutdown impacted traffic in Iraq, or what IPv6 adoption looks like in India? It’s visible on Radar. Just a year and a half later, in March 2022, we launched Autonomous System (ASN) pages on Radar. This has enabled us to bring more granular visibility Continue reading

How Cloudflare uses the world’s greatest collection of performance data to make the world’s fastest global network even faster

Cloudflare operates the fastest network on the planet. We’ve shared an update today about how we are overhauling the software technology that accelerates every server in our fleet, improving speed globally.

That is not where the work stops, though. To improve speed even further, we have to also make sure that our network swiftly handles the Internet-scale congestion that hits it every day, routing traffic to our now-faster servers.

We have invested in congestion control for years. Today, we are excited to share how we are applying a superpower of our network, our massive Free Plan user base, to optimize performance and find the best way to route traffic across our network for all our customers globally.

Early results have seen performance increases that average 10% faster than the prior baseline. We achieved this by applying different algorithmic methods to improve performance based on the data we observe about the Internet each day. We are excited to begin rolling out these improvements to all customers.

The Internet is a massive collection of interconnected networks, each composed of many machines (“nodes”). Data is transmitted by breaking it up into small packets, and passing them Continue reading

Announcing Cloudflare Email Service’s private beta

If you are building an application, you rely on email to communicate with your users. You validate their signup, notify them about events, and send them invoices through email. The service continues to find new purpose with agentic workflows and other AI-powered tools that rely on a simple email as an input or output.

And it is a pain for developers to manage. It’s frequently the most annoying burden for most teams. Developers deserve a solution that is simple, reliable, and deeply integrated into their workflow. 

Today, we're excited to announce just that: the private beta of Email Sending, a new capability that allows you to send transactional emails directly from Cloudflare Workers. Email Sending joins and expands our popular Email Routing product, and together they form the new Cloudflare Email Service — a single, unified developer experience for all your email needs.

With Cloudflare Email Service, we’re distilling our years of experience securing and routing emails, and combining it with the power of the developer platform. Now, sending an email is as easy as adding a binding to a Worker and calling send:

export default {
  async fetch(request, env, ctx) {

    await env.SEND_EMAIL.send({
      to: [{  Continue reading

Announcing the Cloudflare Data Platform: ingest, store, and query your data directly on Cloudflare

For Developer Week in April 2025, we announced the public beta of R2 Data Catalog, a fully managed Apache Iceberg catalog on top of Cloudflare R2 object storage. Today, we are building on that foundation with three launches:

• Cloudflare Pipelines receives events sent via Workers or HTTP, transforms them with SQL, and ingests them into Iceberg or as files on R2

• R2 Data Catalog manages the Iceberg metadata and now performs ongoing maintenance, including compaction, to improve query performance

• R2 SQL is our in-house distributed SQL engine, designed to perform petabyte-scale queries over your data in R2

Together, these products make up the Cloudflare Data Platform, a complete solution for ingesting, storing, and querying analytical data tables.

Like all Cloudflare Developer Platform products, they run on our global compute infrastructure. They’re built around open standards and interoperability. That means that you can bring your own Iceberg query engine — whether that's PyIceberg, DuckDB, or Spark — connect with other platforms like Databricks and Snowflake — and pay no egress fees to access your data.

Analytical data is critical for modern companies. It allows you to understand your user’s behavior, your company’s performance, and alerts you to issues. Continue reading

Choice: the path to AI sovereignty

Every government is laser-focused on the potential for national transformation by AI. Many view AI as an unparalleled opportunity to solve complex national challenges, drive economic growth, and improve the lives of their citizens. Others are concerned about the risks AI can bring to its society and economy. Some sit somewhere between these two perspectives. But as plans are drawn up by governments around the world to address the question of AI development and adoption, all are grappling with the critical question of sovereignty — how much of this technology, mostly centered in the United States and China, needs to be in their direct control? 

Each nation has their own response to that question — some seek ‘self-sufficiency’ and total authority. Others, particularly those that do not have the capacity to build the full AI technology stack, are approaching it layer-by-layer, seeking to build on the capacities their country does have and then forming strategic partnerships to fill the gaps. 

We believe AI sovereignty at its core is about choice. Each nation should have the ability to select the right tools for the task, to control its own data, and to deploy applications at will, all without being Continue reading

Every Cloudflare feature, available to everyone

Over the next year Cloudflare will make nearly every feature we offer available to any customer who wants to buy and use it regardless of whether they are an enterprise account. No need to pick up a phone and talk to a sales team member. No requirement to find time with a solutions engineer in our team to turn on a feature. No contract necessary. We believe that if you want to use something we offer, you should just be able to buy it.

Today’s launch starts by bringing Single Sign-On (SSO) into our dashboard out of our enterprise plan and making it available to any user. That capability is the first of many. We will be sharing updates over the next few months as more and more features become available for purchase on any plan.

We are also making a commitment to ensuring that all future releases will follow this model. The goal is not to restrict new tools to the enterprise tier for some amount of time before making them widely available. We believe helping build a better Internet means making sure the best tools are available to anyone who needs them.

It’s not Continue reading

Safe in the sandbox: security hardening for Cloudflare Workers

As a serverless cloud provider, we run your code on our globally distributed infrastructure. Being able to run customer code on our network means that anyone can take advantage of our global presence and low latency. Workers isn’t just efficient though, we also make it simple for our users. In short: You write code. We handle the rest.

Part of 'handling the rest' is making Workers as secure as possible. We have previously written about our security architecture. Making Workers secure is an interesting problem because the whole point of Workers is that we are running third party code on our hardware. This is one of the hardest security problems there is: any attacker has the full power available of a programming language running on the victim's system when they are crafting their attacks.

This is why we are constantly updating and improving the Workers Runtime to take advantage of the latest improvements in both hardware and software. This post shares some of the latest work we have been doing to keep Workers secure.

Some background first: Workers is built around the V8 JavaScript runtime, originally developed for Chromium-based browsers like Chrome. This gives us a head start, because V8 Continue reading

R2 SQL: a deep dive into our new distributed query engine

How do you run SQL queries over petabytes of data… without a server?

We have an answer for that: R2 SQL, a serverless query engine that can sift through enormous datasets and return results in seconds.

This post details the architecture and techniques that make this possible. We'll walk through our Query Planner, which uses R2 Data Catalog to prune terabytes of data before reading a single byte, and explain how we distribute the work across Cloudflare’s global network, Workers and R2 for massively parallel execution.

During Developer Week 2025, we launched R2 Data Catalog, a managed Apache Iceberg catalog built directly into your Cloudflare R2 bucket. Iceberg is an open table format that provides critical database features like transactions and schema evolution for petabyte-scale object storage. It gives you a reliable catalog of your data, but it doesn’t provide a way to query it.

Until now, reading your R2 Data Catalog required setting up a separate service like Apache Spark or Trino. Operating these engines at scale is not easy: you need to provision clusters, manage resource usage, and be responsible for their availability, none of which contributes to the primary goal of Continue reading

Partnering to make full-stack fast: deploy PlanetScale databases directly from Workers

We’re not burying the lede on this one: you can now connect Cloudflare Workers to your PlanetScale databases directly and ship full-stack applications backed by Postgres or MySQL. 

We’ve teamed up with PlanetScale because we wanted to partner with a database provider that we could confidently recommend to our users: one that shares our obsession with performance, reliability and developer experience. These are all critical factors for any development team building a serious application. 

Now, when connecting to PlanetScale databases, your connections are automatically configured for optimal performance with Hyperdrive, ensuring that you have the fastest access from your Workers to your databases, regardless of where your Workers are running.

As Workers has matured into a full-stack platform, we’ve introduced more options to facilitate your connectivity to data. With Workers KV, we made it easy to store configuration and cache unstructured data on the edge. With D1 and Durable Objects, we made it possible to build multi-tenant apps with simple, isolated SQL databases. And with Hyperdrive, we made connecting to external databases fast and scalable from Workers.

Today, we’re introducing a new choice for building on Cloudflare: Postgres and MySQL PlanetScale databases, directly Continue reading

Cloudflare’s developer platform keeps getting better, faster, and more powerful. Here’s everything that’s new.

When you build on Cloudflare, we consider it our job to do the heavy lifting for you. That’s been true since we introduced Cloudflare Workers in 2017, when we first provided a runtime for you where you could just focus on building. 

That commitment is still true today, and many of today’s announcements are focused on just that — removing friction where possible to free you up to build something great. 

There are only so many blog posts we can write (and that you can read)! We have been busy on a much longer list of new improvements, and many of them we’ve been rolling out consistently over the course of the year. Today’s announcement breaks down all the new capabilities in detail, in one single post. The features being released today include:

• Use more APIs from Node.js — including node:fs and node:https

• Use models from different providers in AI Search (formerly AutoRAG)

• Deploy larger container instances and more concurrent instances to our Containers platform

• Run 30 concurrent headless web browsers (previously 10), via the Browser Rendering API

• Use the Playwright browser automation library with the Browser Rendering API — now fully supported and GA

• Continue reading

A year of improving Node.js compatibility in Cloudflare Workers

We've been busy.

Compatibility with the broad JavaScript developer ecosystem has always been a key strategic investment for us. We believe in open standards and an open web. We want you to see Workers as a powerful extension of your development platform with the ability to just drop code in that Just Works. To deliver on this goal, the Cloudflare Workers team has spent the past year significantly expanding compatibility with the Node.js ecosystem, enabling hundreds (if not thousands) of popular npm modules to now work seamlessly, including the ever popular express framework.

We have implemented a substantial subset of the Node.js standard library, focusing on the most commonly used, and asked for, APIs. These include:

Each of these has been carefully implemented to approximate Node.js' behavior as closely as possible where feasible. Where matching Node.js' behavior is not possible, our implementations will throw a clear error Continue reading

A simpler path to a safer Internet: an update to our CSAM scanning tool

Launching a website or an online community brings people together to create and share. The operators of these platforms, sadly, also have to navigate what happens when bad actors attempt to misuse those destinations to spread the most heinous content like child sexual abuse material (CSAM).

We are committed to helping anyone on the Internet protect their platform from this kind of misuse. We first launched a CSAM Scanning Tool several years ago to give any website on the Internet the ability to programmatically scan content uploaded to their platform for instances of CSAM in partnership with National Center for Missing and Exploited Children (NCMEC), Interpol, and dozens of other organizations committed to protecting children. That release took technology that was only available to the largest social media platforms and provided it to any website.

However, the tool we offered still required setup work that added friction to its adoption. To help our customers file reports to NCMEC, they needed to create their own credentials. That step of creating credentials and sharing them was too confusing or too much work for small site owners. We did our best helping them with secondary reports, but we needed a method that made Continue reading

Automatically Secure: how we upgraded 6,000,000 domains by default to get ready for the Quantum Future

The Internet is in constant motion. Sites scale, traffic shifts, and attackers adapt. Security that worked yesterday may not be enough tomorrow. That’s why the technologies that protect the web — such as Transport Layer Security (TLS) and emerging post-quantum cryptography (PQC) — must also continue to evolve. We want to make sure that everyone benefits from this evolution automatically, so we enabled the strongest protections by default.

During Birthday Week 2024, we announced Automatic SSL/TLS: a service that scans origin server configurations of domains behind Cloudflare, and automatically upgrades them to the most secure encryption mode they support. In the past year, this system has quietly strengthened security for more than 6 million domains — ensuring Cloudflare can always connect to origin servers over the safest possible channel, without customers lifting a finger.

Now, a year after we started enabling Automatic SSL/TLS, we want to talk about these results, why they matter, and how we’re preparing for the next leap in Internet security.

Before diving in, let’s review the basics of Transport Layer Security (TLS). The protocol allows two strangers (like a client and server) to communicate securely.

Every secure web session Continue reading

Giving users choice with Cloudflare’s new Content Signals Policy

If we want to keep the web open and thriving, we need more tools to express how content creators want their data to be used while allowing open access. Today the tradeoff is too limited. Either website operators keep their content open to the web and risk people using it for unwanted purposes, or they move their content behind logins and limit their audience.

To address the concerns our customers have today about how their content is being used by crawlers and data scrapers, we are launching the Content Signals Policy. This policy is a new addition to robots.txt that allows you to express your preferences for how your content can be used after it has been accessed. 

Robots.txt is a plain text file hosted on your domain that implements the Robots Exclusion Protocol. It allows you to instruct which crawlers and bots can access which parts of your site.  Many crawlers and some bots obey robots.txt files, but not all do.

For example, if you wanted to allow all crawlers to access every part of your site, you could host a robots.txt file that Continue reading

Securing today for the quantum future: WARP client now supports post-quantum cryptography (PQC)

The Internet is currently transitioning to post-quantum cryptography (PQC) in preparation for Q-Day, when quantum computers break the classical cryptography that underpins all modern computer systems.  The US National Institute of Standards and Technology (NIST) recognized the urgency of this transition, announcing that classical cryptography (RSA, Elliptic Curve Cryptography (ECC)) must be deprecated by 2030 and completely disallowed by 2035.

Cloudflare is well ahead of NIST’s schedule. Today, over 45% of human-generated Internet traffic sent to Cloudflare’s network is already post-quantum encrypted. Because we believe that a secure and private Internet should be free and accessible to all, we’re on a mission to include PQC in all our products, without specialized hardware, and at no extra cost to our customers and end users.

That’s why we’re proud to announce that Cloudflare’s WARP client now supports post-quantum key agreement — both in our free consumer WARP client 1.1.1.1, and in our enterprise WARP client, the Cloudflare One Agent. 

This upgrade of the WARP client to post-quantum key agreement provides end users with immediate protection for their Internet traffic against harvest-now-decrypt-later attacks. The value Continue reading

Securing data in SaaS to SaaS applications

The recent Salesloft breach taught us one thing: connections between SaaS applications are hard to monitor and create blind spots for security teams with disastrous side effects. This will likely not be the last breach of this type.

To fix this, Cloudflare is working towards a set of solutions that consolidates all SaaS connections via a single proxy, for easier monitoring, detection and response. A SaaS to SaaS proxy for everyone.

As we build this, we need feedback from the community, both data owners and SaaS platform providers. If you are interested in gaining early access, please sign up here.

SaaS platform providers, who often offer marketplaces for additional applications, store data on behalf of their customers and ultimately become the trusted guardians. As integrations with marketplace applications take place, that guardianship is put to the test. A key breach in any one of these integrations can lead to widespread data exfiltration and tampering. As more apps are added the attack surface grows larger. Security teams who work for the data owner have no ability, today, to detect and react to any potential breach.

In this post we explain the underlying technology required to make this work and help keep Continue reading

To build a better Internet in the age of AI, we need responsible AI bot principles. Here’s our proposal.

Cloudflare has a unique vantage point: we see not only how changes in technology shape the Internet, but also how new technologies can unintentionally impact different stakeholders. Take, for instance, the increasing reliance by everyday Internet users on AI–powered chatbots and search summaries. On the one hand, end users are getting information faster than ever before. On the other hand, web publishers, who have historically relied on human eyeballs to their website to support their businesses, are seeing a dramatic decrease in those eyeballs, which can reduce their ability to create original high-quality content. This cycle will ultimately hurt end users and AI companies (whose success relies on fresh, high-quality content to train models and provide services) alike.

We are indisputably at a point in time when the Internet needs clear “rules of the road” for AI bot behavior (a note on terminology: throughout this blog we refer to AI bots and crawlers interchangeably). We have had ongoing cross-functional conversations, both internally and with stakeholders and partners across the world, and it’s clear to us that the Internet at large needs key groups — publishers and content creators, bot operators, and Internet infrastructure and cybersecurity companies — to reach a Continue reading

Cloudflare Confidence Scorecards – making AI safer for the Internet

Security and IT teams face an impossible balancing act: Employees are adopting AI tools every day, but each tool carries unique risks tied to compliance, data privacy, and security practices. Employees using these tools without seeking prior approval leads to a new type of Shadow IT which is referred to as Shadow AI. Preventing Shadow AI requires manually vetting each AI application to determine whether it should be approved or disapproved. This isn’t scalable. And blanket bans of AI applications will only drive AI usage deeper underground, making it harder to secure.

That’s why today we are launching Cloudflare Application Confidence Scorecards. This is part of our new suite of AI Security features within the Cloudflare One SASE platform. These scores bring scale and automation to the labor- and time-intensive task of evaluating generative AI and SaaS applications one by one. Instead of spending hours trying to find AI applications’ compliance certifications or data-handling practices, evaluators get a clear score that reflects an application’s safety and trustworthiness. With that signal, decision makers within organizations can confidently set policies or apply guardrails where needed, and block risky tools so their organizations can embrace innovation without compromising security.

Our Cloudflare Application Confidence Continue reading