Workers Builds connects your Worker to a Git repository, and automates building and deploying your code on each pushed change.
To make CI/CD pipelines even more flexible, Workers Builds now automatically injects default environment variables into your build process (much like the defaults in Cloudflare Pages projects). You can use these variables to customize your build process based on the deployment context, such as the branch or commit.
The following environment variables are injected by default:
Environment Variable
Injected value
Example use-case
CI
true
Changing build behavior when run on CI versus locally
WORKERS_CI
1
Changing build behavior when run on Workers Builds versus locally
WORKERS_CI_BUILD_UUID
<build-uuid-of-current-build>
Passing the Build UUID along to custom workflows
WORKERS_CI_COMMIT_SHA
<sha1-hash-of-current-commit>
Passing current commit ID to error reporting, for example, Sentry
WORKERS_CI_BRANCH
<branch-name-from-push-event
Customizing build based on branch, for example, disabling debug logging on production
You can override these default values and add your own custom environment variables by navigating to your Worker > Settings > Environment variables.
Workers native integrations were originally launched in May 2023 ↗︎ to connect to popular database and observability providers with your Worker in just a few clicks. We are changing how developers connect Workers to these external services. The Integrations tab in the dashboard has been removed in favor of a more direct, command-line-based approach using Wrangler secrets.
What's changed
Integrations tab removed: The integrations setup flow is no longer available in the Workers dashboard.
Manual secret configuration: New connections should be configured by adding credentials as secrets to your Workers using npx wrangler secret put commands.
Impact on existing integrations
Existing integrations will continue to work without any changes required. If you have integrations that were previously created through the dashboard, they will remain functional.
Updating existing integrations
If you'd like to modify your existing integration, you can update the secrets, environment variables, or Tail Workers that were created from the original integration setup.
Update secrets: Use npx wrangler secret put <SECRET_NAME> to update credential values.
Modify environment variables: Update variables through the dashboard or Wrangler configuration.
Dashboard management: Access your Worker's settings in the Cloudflare dashboard ↗︎ to modify connections created by our removed native integrations feature.
If you have previously set up an observability integration with Sentry ↗︎, the following environment variables were set and are still modifiable:
BLOCKED_HEADERS: headers to exclude sending to Sentry
EXCEPTION_SAMPLING_RATE: number from 0 - 100, where 0 = no events go through to Sentry, and 100 = all events go through to Sentry
STATUS_CODES_TO_SAMPLING_RATES: a map of status codes -- like 400 or with wildcards like 4xx -- to sampling rates described above
Setting up new database and observability connections
For new connections, refer to our step-by-step guides on connecting to popular database and observability providers including: Sentry, Turso, Neon, Supabase, PlanetScale, Upstash, Xata.
With the release of the Cloudflare adapter for Open Next v1.0.0 in May 2025, we already had followups plans to improve performance and size ↗︎.
@opennextjs/cloudflare v1.2 released on June 5, 2025 delivers on these enhancements. By removing babel from the app code and dropping a dependency on @ampproject/toolbox-optimizer, we were able to reduce generated bundle sizes. Additionally, by stopping preloading of all app routes, we were able to improve the cold start time.
This means that users will now see a decrease from 14 to 8MiB (2.3 to 1.6MiB gzipped) in generated bundle size for a Next app created via create-next-app, and typically 100ms faster startup times for their medium-sized apps.
Users only need to update to the latest version of @opennextjs/cloudflare to automatically benefit from these improvements.
Note that we published CVE-2005-6087 ↗︎ for a SSRF vulnerability in the @opennextjs/cloudflare package.
The vulnerability has been fixed from @opennextjs/cloudflare v1.3.0 onwards. Please update to any version after this one.
You can now visualize, explore and modify your Worker’s architecture directly in the Cloudflare dashboard, making it easier to understand how your application connects to Cloudflare resources like D1 databases, Durable Objects, KV namespaces, and more.
With this new view, you can easily:
Explore existing bindings in a visual, architecture-style diagram
Add and manage bindings directly from the same interface
Discover the full range of compute, storage, AI, and media resources you can attach to your Workers application.
To get started, head to the Cloudflare dashboard ↗︎ and open the Bindings tab of any Workers application.
Previously, this was only possible if your Worker ran locally using the Wrangler CLI ↗︎, and now you can do all the same things if your Worker uses Vite ↗︎.
When you run vite, you'll now see a debug URL in your console:
VITE v6.3.5 ready in 461 ms ➜ Local: http://localhost:5173/ ➜ Network: use --host to expose ➜ Debug: http://localhost:5173/__debug ➜ press h + enter to show help
Open the URL in Chrome, and an instance of Chrome Devtools will open and connect to your Worker running locally. You can then use Chrome Devtools to debug and introspect performance issues. For example, you can navigate to the Performance tab to understand where CPU time is spent in your Worker:
For more information on how to get the most out of Chrome Devtools, refer to the following docs:
In Cloudflare Workers, you can now attach an event listener to Request objects, using the signal property ↗︎. This allows you to perform tasks when the request to your Worker is canceled by the client. To use this feature, you must set the enable_request_signal compatibility flag.
You can use a listener to perform cleanup tasks or write to logs before your Worker's invocation ends. For example, if you run the Worker below, and then abort the request from the client, a log will be written:
index.jsjs
export default { async fetch(request, env, ctx) { // This sets up an event listener that will be called if the client disconnects from your // worker. request.signal.addEventListener("abort", () => { console.log("The request was aborted!"); }); const { readable, writable } = new IdentityTransformStream(); sendPing(writable); return new Response(readable, { headers: { "Content-Type": "text/plain" }, }); },};async function sendPing(writable) { const writer = writable.getWriter(); const enc = new TextEncoder(); for (;;) { // Send 'ping' every second to keep the connection alive await writer.write(enc.encode("ping\r\n")); await scheduler.wait(1000); }}
index.tsts
export default { async fetch(request, env, ctx): Promise<Response> { // This sets up an event listener that will be called if the client disconnects from your // worker. request.signal.addEventListener('abort', () => { console.log('The request was aborted!'); }); const { readable, writable } = new IdentityTransformStream(); sendPing(writable); return new Response(readable, { headers: { 'Content-Type': 'text/plain' } }); },} satisfies ExportedHandler<Env>;async function sendPing(writable: WritableStream): Promise<void> { const writer = writable.getWriter(); const enc = new TextEncoder(); for (;;) { // Send 'ping' every second to keep the connection alive await writer.write(enc.encode('ping\r\n')); await scheduler.wait(1000); }}
You can now create Durable Objects using
Python Workers. A Durable Object is a special kind of
Cloudflare Worker which uniquely combines compute with storage, enabling stateful
long-running applications which run close to your users. For more info see
here.
You can define a Durable Object in Python in a similar way to JavaScript:
We are adding source origin restrictions to
the Media Transformations beta. This allows customers to restrict what sources
can be used to fetch images and video for transformations. This feature is the
same as --- and uses the same settings as ---
Image Transformations sources.
When transformations is first enabled, the default setting only allows
transformations on images and media from the same website or domain being used to make
the transformation request. In other words, by default, requests to
example.com/cdn-cgi/media can only reference originals on example.com.
Adding access to other sources, or allowing any source,
is easy to do
in the Transformations tab under Stream. Click each domain enabled for
Transformations and set its sources list to match the needs of your content. The
user making this change will need permission to edit zone settings.
This can reduce memory leaks when using WebAssembly-based Workers, which includes Python Workers and Rust Workers. The FinalizationRegistry works by enabling toolchains such as Emscripten ↗︎ and wasm-bindgen ↗︎ to automatically free WebAssembly heap allocations. If you are using WASM and seeing Exceeded Memory errors and cannot determine a cause using memory profiling, you may want to enable the FinalizationRegistry.
For more information refer to the enable_weak_ref compatibility flag documentation.
You can now create Python Workers which are executed via a cron trigger.
This is similar to how it's done in JavaScript Workers, simply define a scheduled event
listener in your Worker:
from workers import handler@handlerasync def on_scheduled(event, env, ctx): print("cron processed")
Define a cron trigger configuration in your Wrangler configuration file:
{ "triggers": { // Schedule cron triggers: // - At every 3rd minute // - At 15:00 (UTC) on first day of the month // - At 23:59 (UTC) on the last weekday of the month "crons": [ "*/3 * * * *", "0 15 1 * *", "59 23 LW * *" ] }}
Previously, a request to the Workers Create Route API always returned null for "script" and an empty string for "pattern" even if the request was successful.
The Workers and Workers for Platforms secrets APIs are now properly documented in the Cloudflare OpenAPI docs. Previously, these endpoints were not publicly documented, leaving users confused on how to directly manage their secrets via the API. Now, you can find the proper endpoints in our public documentation, as well as in our API Library SDKs such as cloudflare-typescript ↗︎ (>4.2.0) and cloudflare-python ↗︎ (>4.1.0).
Note the cloudflare_workers_secret and cloudflare_workers_for_platforms_script_secretTerraform resources ↗︎ are being removed in a future release. This resource is not recommended for managing secrets. Users should instead use the:
Secrets Store with the "Secrets Store Secret" binding on Workers and Workers for Platforms Script Upload
Cloudflare Stream has completed an infrastructure upgrade for our Live WebRTC beta support which brings increased scalability and improved playback performance to all customers. WebRTC allows broadcasting directly from a browser (or supported WHIP client) with ultra-low latency to tens of thousands of concurrent viewers across the globe.
Additionally, as part of this upgrade, the WebRTC beta now supports Signed URLs to protect playback, just like our standard live stream options (HLS/DASH).
The Overview tab shows logs from all your Workers in one place. The Invocations view groups logs together by invocation, which refers to the specific trigger that started the execution of the Worker (i.e. fetch). The Events view shows logs in the order they were produced, based on timestamp. Previously, you could only view logs for a single Worker.
The Investigate tab presents a Query Builder, which helps you write structured queries to investigate and visualize your logs. The Query Builder can help answer questions such as:
Which paths are experiencing the most 5XX errors?
What is the wall time distribution by status code for my Worker?
What are the slowest requests, and where are they coming from?
Who are my top N users?
The Query Builder can use any field that you store in your logs as a key to visualize, filter, and group by. Use the Query Builder to quickly access your data, build visualizations, save queries, and share them with your team.
Workers Logs is now Generally Available
Workers Logs is now Generally Available. With a small change to your Wrangler configuration, Workers Logs ingests, indexes, and stores all logs emitted from your Workers for up to 7 days.
We've introduced a number of changes during our beta period, including:
Dashboard enhancements with customizable fields as columns in the Logs view and support for invocation-based grouping
Performance improvements to ensure no adverse impact
The API documents three endpoints: list the keys in the telemetry dataset, run a query, and list the unique values for a key. For more, visit our REST API documentation ↗︎.
Visit the docs to learn more about the capabilities and methods exposed by the Query Builder. Start using Workers Logs and the Query Builder today by enabling observability for your Workers:
For Workers Logpush, CPU and Wall time are surfaced at the top level of the Workers Trace Events object. All new jobs will have these new fields included by default. Existing jobs need to be updated to include CPU time and Wall time.
You can use a Workers Logs filter to search for logs where Wall time exceeds 100ms.
You can also use the Workers Observability Query Builder ↗︎ to find the median CPU time and median Wall time for all of your Workers.
You can now add a Deploy to Cloudflare button to the README of your Git repository containing a Workers application — making it simple for other developers to quickly set up and deploy your project!
The Deploy to Cloudflare button:
Creates a new Git repository on your GitHub/ GitLab account: Cloudflare will automatically clone and create a new repository on your account, so you can continue developing.
Automatically provisions resources the app needs: If your repository requires Cloudflare primitives like a Workers KV namespace, a D1 database, or an R2 bucket, Cloudflare will automatically provision them on your account and bind them to your Worker upon deployment.
Configures Workers Builds (CI/CD): Every new push to your production branch on your newly created repository will automatically build and deploy courtesy of Workers Builds.
To create a Deploy to Cloudflare button in your README, you can add the following snippet, including your Git repository URL:
[](https://deploy.workers.cloudflare.com/?url=<YOUR_GIT_REPO_URL>)
Check out our documentation for more information on how to set up a deploy button for your application and best practices to ensure a successful deployment for other developers.
When you use @cloudflare/vite-plugin, you can use Vite's local development server and build tooling, while ensuring that while developing, your code runs in workerd ↗︎, the open-source Workers runtime.
This lets you get the best of both worlds for a full-stack app — you can use Hot Module Replacement ↗︎ from Vite right alongside Durable Objects and other runtime APIs and bindings that are unique to Cloudflare Workers.
You can build any type of application with @cloudflare/vite-plugin, using any rendering mode, from single page applications (SPA) and static sites to server-side rendered (SSR) pages and API routes.
React Router v7 (Remix) is the first full-stack framework to provide full support for Cloudflare Vite plugin, allowing you to use all parts of Cloudflare's developer platform, without additional build steps.
You can also build complete full-stack apps on Workers without a framework — "just use Vite" ↗︎ and React together, and build a back-end API in the same Worker. Follow our React SPA with an API tutorial to learn how.
Configuration
If you're already using Vite ↗︎ in your build and development toolchain, you can start using our plugin with minimal changes to your vite.config.ts:
vite.config.tsts
import { defineConfig } from "vite";import { cloudflare } from "@cloudflare/vite-plugin";export default defineConfig({ plugins: [cloudflare()],});
You can now capture a maximum of 256 KB of log events per Workers invocation, helping you gain better visibility into application behavior.
All console.log() statements, exceptions, request metadata, and headers are automatically captured during the Worker invocation and emitted
as JSON object. Workers Logs deserializes
this object before indexing the fields and storing them. You can also capture, transform, and export the JSON object in a
Tail Worker.
256 KB is a 2x increase from the previous 128 KB limit. After you exceed this limit, further context associated with the request will not be
recorded in your logs.
This limit is automatically applied to all Workers.
You can now run a Worker for up to 5 minutes of CPU time for each request.
Previously, each Workers request ran for a maximum of 30 seconds of CPU time — that is the time that a Worker is actually performing a task (we still allowed unlimited wall-clock time, in case you were waiting on slow resources). This
meant that some compute-intensive tasks were impossible to do with a Worker. For instance,
you might want to take the cryptographic hash of a large file from R2. If
this computation ran for over 30 seconds, the Worker request would have timed out.
By default, Workers are still limited to 30 seconds of CPU time. This protects developers
from incurring accidental cost due to buggy code.
By changing the cpu_ms value in your Wrangler configuration, you can opt in to
any value up to 300,000 (5 minutes).
{ // ...rest of your configuration... "limits": { "cpu_ms": 300000, }, // ...rest of your configuration...}
Source maps are now Generally Available (GA). You can now be uploaded with a maximum gzipped size of 15 MB.
Previously, the maximum size limit was 15 MB uncompressed.
Source maps help map between the original source code and the transformed/minified code that gets deployed
to production. By uploading your source map, you allow Cloudflare to map the stack trace from exceptions
onto the original source code making it easier to debug.
With no source maps uploaded: notice how all the Javascript has been minified to one file, so the stack trace is missing information on file name, shows incorrect line numbers, and incorrectly references js instead of ts.
With source maps uploaded: all methods reference the correct files and line numbers.
Uploading source maps and stack trace remapping happens out of band from the Worker execution,
so source maps do not affect upload speed, bundle size, or cold starts. The remapped stack
traces are accessible through Tail Workers, Workers Logs, and Workers Logpush.
To enable source maps, add the following to your
Pages Function's or Worker's wrangler configuration:
Update: Mon Mar 24th, 11PM UTC: Next.js has made further changes to address a smaller vulnerability introduced in the patches made to its middleware handling. Users should upgrade to Next.js versions 15.2.4, 14.2.26, 13.5.10 or 12.3.6. If you are unable to immediately upgrade or are running an older version of Next.js, you can enable the WAF rule described in this changelog as a mitigation.
Update: Mon Mar 24th, 8PM UTC: Next.js has now backported the patch for this vulnerability ↗︎ to cover Next.js v12 and v13. Users on those versions will need to patch to 13.5.9 and 12.3.5 (respectively) to mitigate the vulnerability.
Update: Sat Mar 22nd, 4PM UTC: We have changed this WAF rule to opt-in only, as sites that use auth middleware with third-party auth vendors were observing failing requests.
We strongly recommend updating your version of Next.js (if eligible) to the patched versions, as your app will otherwise be vulnerable to an authentication bypass attack regardless of auth provider.
Enable the Managed Rule (strongly recommended)
This rule is opt-in only for sites on the Pro plan or above in the WAF managed ruleset.
To enable the rule:
Head to Security > WAF > Managed rules in the Cloudflare dashboard for the zone (website) you want to protect.
Click the three dots next to Cloudflare Managed Ruleset and choose Edit
Scroll down and choose Browse Rules
Search for CVE-2025-29927 (ruleId: 34583778093748cc83ff7b38f472013e)
Change the Status to Enabled and the Action to Block. You can optionally set the rule to Log, to validate potential impact before enabling it. Log will not block requests.
Click Next
Scroll down and choose Save
This will enable the WAF rule and block requests with the x-middleware-subrequest header regardless of Next.js version.
Create a WAF rule (manual)
For users on the Free plan, or who want to define a more specific rule, you can create a Custom WAF rule to block requests with the x-middleware-subrequest header regardless of Next.js version.
To create a custom rule:
Head to Security > WAF > Custom rules in the Cloudflare dashboard for the zone (website) you want to protect.
Give the rule a name - e.g. next-js-CVE-2025-29927
Set the matching parameters for the rule match any request where the x-middleware-subrequest header exists per the rule expression below.
Set the action to 'block'. If you want to observe the impact before blocking requests, set the action to 'log' (and edit the rule later).
Deploy the rule.
Next.js CVE-2025-29927
We've made a WAF (Web Application Firewall) rule available to all sites on Cloudflare to protect against the Next.js authentication bypass vulnerability ↗︎ (CVE-2025-29927) published on March 21st, 2025.
Note: This rule is not enabled by default as it blocked requests across sites for specific authentication middleware.
This managed rule protects sites using Next.js on Workers and Pages, as well as sites using Cloudflare to protect Next.js applications hosted elsewhere.
This rule has been made available (but not enabled by default) to all sites as part of our WAF Managed Ruleset and blocks requests that attempt to bypass authentication in Next.js applications.
The vulnerability affects almost all Next.js versions, and has been fully patched in Next.js 14.2.26 and 15.2.4. Earlier, interim releases did not fully patch this vulnerability.
Users on older versions of Next.js (11.1.4 to 13.5.6) did not originally have a patch available, but this the patch for this vulnerability and a subsequent additional patch have been backported to Next.js versions 12.3.6 and 13.5.10 as of Monday, March 24th. Users on Next.js v11 will need to deploy the stated workaround or enable the WAF rule.
The managed WAF rule mitigates this by blocking external user requests with the x-middleware-subrequest header regardless of Next.js version, but we recommend users using Next.js 14 and 15 upgrade to the patched versions of Next.js as an additional mitigation.
Smart Placement is a unique Cloudflare feature that can make decisions to move your Worker to run in a more optimal location (such as closer to a database). Instead of always running in the default location (the one closest to where the request is received), Smart Placement uses certain “heuristics” (rules and thresholds) to decide if a different location might be faster or more efficient.
Previously, if these heuristics weren't consistently met, your Worker would revert to running in the default location—even after it had been optimally placed. This meant that if your Worker received minimal traffic for a period of time, the system would reset to the default location, rather than remaining in the optimal one.
Now, once Smart Placement has identified and assigned an optimal location, temporarily dropping below the heuristic thresholds will not force a return to default locations. For example in the previous algorithm, a drop in requests for a few days might return to default locations and heuristics would have to be met again. This was problematic for workloads that made requests to a geographically located resource every few days or longer. In this scenario, your Worker would never get placed optimally. This is no longer the case.
You can now access bindings
from anywhere in your Worker by importing the env object from cloudflare:workers.
Previously, env could only be accessed during a request. This meant that
bindings could not be used in the top-level context of a Worker.
Now, you can import env and access bindings such as secrets
or environment variables in the
initial setup for your Worker:
import { env } from "cloudflare:workers";import ApiClient from "example-api-client";// API_KEY and LOG_LEVEL now usable in top-level scopeconst apiClient = ApiClient.new({ apiKey: env.API_KEY });const LOG_LEVEL = env.LOG_LEVEL || "info";export default { fetch(req) { // you can use apiClient or LOG_LEVEL, configured before any request is handled },};
Additionally, env was normally accessed as a argument to a Worker's entrypoint handler,
such as fetch.
This meant that if you needed to access a binding from a deeply nested function,
you had to pass env as an argument through many functions to get it to the
right spot. This could be cumbersome in complex codebases.
Now, you can access the bindings from anywhere in your codebase
without passing env as an argument:
// helpers.jsimport { env } from "cloudflare:workers";// env is *not* an argument to this functionexport async function getValue(key) { let prefix = env.KV_PREFIX; return await env.KV.get(`${prefix}-${key}`);}
You can now retry your Cloudflare Pages and Workers builds directly from GitHub. No need to switch to the Cloudflare Dashboard for a simple retry!
Let\u2019s say you push a commit, but your build fails due to a spurious error like a network timeout. Instead of going to the Cloudflare Dashboard to manually retry, you can now rerun the build with just a few clicks inside GitHub, keeping you inside your workflow.
For Pages and Workers projects connected to a GitHub repository:
When a build fails, go to your GitHub repository or pull request
Select the failed Check Run for the build
Select "Details" on the Check Run
Select "Rerun" to trigger a retry build for that commit