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Announcing Workers for Platforms: making every application on the Internet more programmable


8 min read

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Announcing Workers for Platforms: making every application on the Internet more programmable

As a business, whether a startup or Fortune 500 company, your number one priority is to make your customers happy and successful with your product. To your customers, however, success and happiness sometimes seems to be just one feature away.

If only you could customize X, we’ll be able to use your product” - the largest prospect in your pipeline. “If you just let us do Y,  we’ll expand our usage of your product by 10x” - your most strategic existing customer.

You want your product to be everything to everybody, but engineering can only keep up so quickly, so, what gives?

Today, we’re announcing Workers for Platforms, our tool suite to help make any product programmable, and help our customers deliver value to their customers and developers instantaneously.

A more programmable interface

One way to give your customers the ability to programmatically interact with your product is by providing them with APIs. That is a big part of why APIs are so prolific today — enabling code (whether your own, or that of a 3rd party) to engage with your applications is nothing short of revolutionary.

But there’s still a problem. While APIs can give developers the ability to interact with your application programmatically, developers are ultimately always limited by the abstractions exposed to them by the API. You, an application owner, have to have predicted how the customer would use your product, and then built out the API to support the use case. If there’s one thing I have learned as a product manager, it’s almost impossible to predict how customers will use a product. And if there’s a second thing I’ve learned, it’s that even with plentiful engineering resources, it’s also almost impossible to build all the functionality required to keep said customers happy.

There is another way, however.

Functions, in contrast to APIs, provide the lowest level primitives (rather than abstractions on top of them). This lets the developer define the right behavior from there — and they can even define their own APIs on top.

In this sense, functions and APIs are actually complementary to each other — you may even choose to call another API directly from your function. For example, if you’re handling an event in a messaging system, you could implement your own feature to send an email by calling an email API, or create a ticket in your ticketing system, etc.

This gets at why we’re so excited about Workers for Platforms: it enables you to expose a direct way for your customers’ developers to bring their own logic to any application. We think it’s going to unlock a wave of customer-led innovation on top of companies that adopt it, and has the potential to be as impactful to building applications on the web as the API has been.

A better experience for developers

While Workers for Platforms expose a more powerful paradigm for making product programmable, they also result in a better experience for you as a developer.

Today, as a developer, before you can even get started using APIs or webhooks, there’s a list of tedious tasks you have to deal with first. First, you have to set up somewhere to host your code, whether a server (or serverless function), and expose it via an external endpoint to be able. You have to deal with ops, custom tokens, figuring out the new authentication schema, all before you get started. Then you have to maintain that service, and make sure that it stays up to ensure that events are always processed properly.

With functions embedded directly into the products you’re using, you can just start writing the code.

Why hasn’t this model been embraced until now?

Allowing developers to program how events work seems obvious, but just because it’s obvious doesn’t mean it’s easy.

At Cloudflare, we encountered this very problem five years ago — we were onboarding larger and larger customers onto our network, each needing to dictate the fate of a request in their own way. While Page Rules offered a way to modify behavior by URL, customers wanted to control behavior based on cookie, header, geolocation, and more!

We realized our engineering team couldn’t keep up with every request, so we decided to allow customers to bend our product to their own needs.

As we looked for an approach to this problem, we looked for a solution that would meet the two following requirements:

  1. Performance requirement: it’s unacceptable for a CDN, which should make your site faster to introduce latency. How do we make this so fast you don’t even notice it’s there?
  2. Security requirement: how do we run untrusted code securely?

While these requirements are especially critical when you offer performance and security products, solving these challenges is critical when giving your customers the ability to program your product. If the function needs to run on the critical path to your user, introducing latency is equally unacceptable. And of course, no one wants to get breached just to have their users be able to program.

Creating a really fast and secure multi-tenant environment is no easy feat.

When we evaluated our options for solving this problem, we first turned to technologies that existed for solving this problem on the server — serverless functions already existed at time, but were powered by containers, which would introduce cold-start, which was, well, a non-starter. So we turned to the browser, or specifically Chrome, which was powered by V8, and decided to take the same approach, and run it on our servers.

And while the approach sounds simple (and perhaps in retrospect obvious, as these things tend to seem), running a large multi-tenant development platform at scale is no small effort. If a part of the purpose of allowing customers to program your offering is to free up engineering efforts to focus on building new features, the effort it takes to maintain and scale such a development platform may defeat the purpose.

What we realized recently was that we weren’t alone in trying to solve this problem.

Companies like Shopify, building their next generation programmable storefront, Oxygen, were trying to solve the same thing. They wanted to enable their customers to run custom storefronts, and be able to offer the best performance possible, while maintaining a secure, multi-tenant environment.

“Shopify is the Internet’s commerce infrastructure, with millions of merchants using the platform,” said Zach Koch, product director, custom storefronts, at Shopify. “Partnering with Cloudflare, we’re able to give developers the tools they need to build unique and performant storefronts. We are excited to work with Cloudflare to alleviate some complexities of building commerce experiences – like scalability and global availability – so that developers can instead focus on what makes their brand distinct.”

How can you build your next platform on Workers for Platforms?

Working with platforms like Shopify to help them address their developers’ needs, helped us realize another thing — developer experience is not one-size-fits-all. That is, while we’re building our platform for a broad set of developers, eCommerce developers might have a much more specialized set of needs, best solved by a tailored developer experience. And, while the underlying technology is the same, making platforms their experiences using the same high level concepts as our direct customers need doesn’t make sense.

Since no one knows your customers better than you, we want you, the platform provider,  to design the best experience for your users. Workers for Platforms exposes a new set of tools and APIs to integrate directly into the deployment flow you want to design (see what we did there?).

Tags API to manage your functions at scale

Using our APIs, whenever a developer wants to deploy a script on your platform, you can call our APIs to deploy a new Worker in the background. Unlike our traditional Workers offering, Workers for Platforms is designed to be used at scale, to manage hundreds of thousands to millions of Cloudflare Workers.

Depending on how you manage your deployment services, or users, we now also provide the option to use tags to manage groupings of scripts. For example, if a user deletes their account, and you would like to make sure all their Workers are cleaned up. With tags, you can now add any arbitrary tags (such as user ID) per script, to enable bulk actions.

Trace Workers

Where there’s smoke, there’s fire, and where there’s code, well, bugs are also bound to be. When giving developers the tools to write and deploy code, you must also give them the means to debug it.

Trace Workers allow you to collect any information about a request that was handled by a Worker, including any logs or exceptions, and pass them onto your customer. A Trace Worker is a Worker that will receive information about the execution of other Workers, and can forward it to a destination of your choosing, enabling use cases such as live logging or long term storage.

Here is a simple trace Worker that sends its trace data to an HTTP endpoint:

addEventListener("trace", event => {
  event.waitUntil(fetch("", {
    method: "POST",
    body: JSON.stringify(event.traces),

Here is an example of what the data in event.traces might look like:

    "scriptName": "Example script",
    "outcome": "exception",
    "eventTimestamp": 1587058642005,
    "event": {
      "request": {
        "url": "",
        "method": "GET",
        "headers": [
          "cf-ray": "57d55f210d7b95f3",
          "x-custom-header-name": "my-header-value"
        "cf": {
          "colo": "SJC"
    "logs": [
        "message": ["string passed to console.log()"],
        "level": "log",
        "timestamp": 1587058642005
    "exceptions": [
        "name": "Error",
        "message": "Threw a sample exception",
        "timestamp": 1587058642005

Chaining multiple Workers together using Dynamic Dispatch

From working with a few of our early customers, another need we were hearing about often was the ability to run your own code, before running your customer’s code. Perhaps you want to run a layer of authentication, sanitize input or output, or even provide useful information downstream (like user or account IDs).

For this you may want to maintain your own Worker. However, when it’s done executing, you want to be able to call the next Worker, with your customer’s code.


let user_worker = dispatcher.get('customer-worker-123');
let response = await user_worker.fetch(request);

Custom domains, and more!

The features above are only the new Workers features we enabled for our customers as of this week, but our goal is to provide all the tools you need to build your platform. For example, you can use Workers for Platforms with Cloudflare for SaaS to create custom domains. (And stay tuned for the “and more!”).

How do I get access?

As is the case with any new product we release, we have no doubt we have so much to learn from our customers and their use cases. Since we want to support you, and make sure you’re set up for success, if you’re interested, we’d love to get to know you and your use case, and get you set up with all the tools you need. To get started, we ask that you fill out our form, and we’ll  get in touch with you.

In the meantime, you’re welcome to get started checking out our developer docs, or saying hi in our Discord.

Just getting started

We faced this problem ourselves five years ago — we needed to give our customers the ability to augment our offering in a way that worked for them, so we did just that when we launched Cloudflare Workers. Allowing our customers to program our global network to meet their needs has enabled us to support more customers on our development platform, while enabling our engineering team to focus on turning the most requested customizations into features.

We look forward to seeing both what your developers build on your platform (and we believe you, yourself will be surprised with the use cases developers come up with that you could never dream up yourself), and what your engineering team is able to tackle in parallel!

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.

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Platform WeekCloudflare WorkersServerlessDevelopersDeveloper Platform

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Rita Kozlov|@ritakozlov_

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