Developer Platform Updates & Release Notes

We've released the next major version of Wrangler, the CLI for Cloudflare Workers — wrangler@4.0.0. Wrangler v4 is a major release focused on updates to underlying systems and dependencies, along with improvements to keep Wrangler commands consistent and clear.

You can run the following command to install it in your projects:

npmyarnpnpmbun

npm i wrangler@latest

yarn add wrangler@latest

pnpm add wrangler@latest

bun add wrangler@latest

Unlike previous major versions of Wrangler, which were foundational rewrites ↗︎ and rearchitectures ↗︎ — Version 4 of Wrangler includes a much smaller set of changes. If you use Wrangler today, your workflow is very unlikely to change.

A detailed migration guide is available and if you find a bug or hit a roadblock when upgrading to Wrangler v4, open an issue on the cloudflare/workers-sdk repository on GitHub ↗︎.

Going forward, we'll continue supporting Wrangler v3 with bug fixes and security updates until Q1 2026, and with critical security updates until Q1 2027, at which point it will be out of support.

We’re removing some of the restrictions in Email Routing so that AI Agents and task automation can better handle email workflows, including how Workers can reply to incoming emails.

It's now possible to keep a threaded email conversation with an Email Worker script as long as:

• The incoming email has to have valid DMARC ↗︎.
• The email can only be replied to once in the same EmailMessage event.
• The recipient in the reply must match the incoming sender.
• The outgoing sender domain must match the same domain that received the email.
• Every time an email passes through Email Routing or another MTA, an entry is added to the References list. We stop accepting replies to emails with more than 100 References entries to prevent abuse or accidental loops.

Here's an example of a Worker responding to Emails using a Workers AI model:

AI model responding to emailsts

import PostalMime from "postal-mime";
import { createMimeMessage } from "mimetext";
import { EmailMessage } from "cloudflare:email";

export default {
	async email(message, env, ctx) {
		const email = await PostalMime.parse(message.raw);
		const res = await env.AI.run("@cf/meta/llama-2-7b-chat-fp16", {
			messages: [
				{
					role: "user", …

You can now access environment variables and secrets on process.env when using the nodejs_compat compatibility flag.

const apiClient = ApiClient.new({ apiKey: process.env.API_KEY });
const LOG_LEVEL = process.env.LOG_LEVEL || "info";

In Node.js, environment variables are exposed via the global process.env object. Some libraries assume that this object will be populated, and many developers may be used to accessing variables in this way.

Previously, the process.env object was always empty unless written to in Worker code. This could cause unexpected errors or friction when developing Workers using code previously written for Node.js.

Now, environment variables, secrets, and version metadata can all be accessed on process.env. …

Hyperdrive now pools database connections in one or more regions close to your database. This means that your uncached queries and new database connections have up to 90% less latency as measured from connection pools.

Hyperdrive query latency decreases by 90% during Hyperdrive's gradual rollout of regional pooling.

By improving placement of Hyperdrive database connection pools, Workers' Smart Placement is now more effective when used with Hyperdrive, ensuring that your Worker can be placed as close to your database as possible.

With this update, Hyperdrive also uses Cloudflare's standard IP address ranges ↗︎ to connect to your database. This enables you to configure the firewall policies (IP access control lists) of your database to only allow access from Cloudflare and Hyperdrive.

Refer to documentation on how Hyperdrive makes connecting to regional databases from Cloudflare Workers fast.

This improvement is enabled on all Hyperdrive configurations.

You can now use bucket locks to set retention policies on your R2 buckets (or specific prefixes within your buckets) for a specified period — or indefinitely. This can help ensure compliance by protecting important data from accidental or malicious deletion.

Locks give you a few ways to ensure your objects are retained (not deleted or overwritten). You can:

• Lock objects for a specific duration, for example 90 days.
• Lock objects until a certain date, for example January 1, 2030.
• Lock objects indefinitely, until the lock is explicitly removed.

Buckets can have up to 1,000 bucket lock rules. Each rule specifies which objects it covers (via prefix) and how long those objects must remain retained.

Here are a couple of examples showing how you can configure bucket lock rules using Wrangler:

Ensure all objects in a bucket are retained for at least 180 days

npx wrangler r2 bucket lock add <bucket> --name 180-days-all --retention-days 180

Prevent deletion or overwriting of all logs indefinitely (via prefix)

Today, we are thrilled to announce Media Transformations, a new service that brings the magic of Image Transformations to short-form video files, wherever they are stored!

For customers with a huge volume of short video — generative AI output, e-commerce product videos, social media clips, or short marketing content — uploading those assets to Stream is not always practical. Sometimes, the greatest friction to getting started was the thought of all that migrating. Customers want a simpler solution that retains their current storage strategy to deliver small, optimized MP4 files. Now you can do that with Media Transformations.

To transform a video or image, enable transformations for your zone, then make a simple request with a specially formatted URL. The result is an MP4 that can be used in an HTML video element without a player library. If your zone already has Image Transformations enabled, then it is ready to optimize videos with Media Transformations, too.

URL formattext

https://example.com/cdn-cgi/media/<OPTIONS>/<SOURCE-VIDEO>

For example, we have a short video of the mobile in Austin's office. The original is nearly 30 megabytes and wider than necessary for this layout. Consider a simple width adjustment:

Example URLtext

https://example.com/cdn-cgi/media/width=640/<SOURCE-VIDEO> …

We've released a release candidate of the next major version of Wrangler, the CLI for Cloudflare Workers — wrangler@4.0.0-rc.0.

You can run the following command to install it and be one of the first to try it out:

npmyarnpnpmbun

npm i wrangler@v4-rc

yarn add wrangler@v4-rc

pnpm add wrangler@v4-rc

bun add wrangler@v4-rc

Unlike previous major versions of Wrangler, which were foundational rewrites ↗︎ and rearchitectures ↗︎ — Version 4 of Wrangler includes a much smaller set of changes. If you use Wrangler today, your workflow is very unlikely to change. Before we release Wrangler v4 and advance past the release candidate stage, we'll share a detailed migration guide in the Workers developer docs. But for the vast majority of cases, you won't need to do anything to migrate — things will just work as they do today. We are sharing this release candidate in advance of the official release of v4, so that you can try it out early and share feedback.

New JavaScript language features that you can now use with Wrangler v4

Version 4 of Wrangler updates the version of esbuild ↗︎ that Wrangler uses internally, allowing you to use modern JavaScript language features, including: …

We've released a new REST API for Browser Rendering in open beta, making interacting with browsers easier than ever. This new API provides endpoints for common browser actions, with more to be added in the future.

With the REST API you can:

• Capture screenshots – Use /screenshot to take a screenshot of a webpage from provided URL or HTML.
• Generate PDFs – Use /pdf to convert web pages into PDFs.
• Extract HTML content – Use /content to retrieve the full HTML from a page. Snapshot (HTML + Screenshot) – Use /snapshot to capture both the page's HTML and a screenshot in one request
• Scrape Web Elements – Use /scrape to extract specific elements from a page.

For example, to capture a screenshot:

Screenshot examplebash

curl -X POST 'https://api.cloudflare.com/client/v4/accounts/<accountId>/browser-rendering/screenshot' \
  -H 'Authorization: Bearer <apiToken>' \
  -H 'Content-Type: application/json' \
  -d '{
    "html": "Hello World!",
    "screenshotOptions": {
      "type": "webp",
      "omitBackground": true
    }
  }' \
  --output "screenshot.webp"

Learn more in our documentation.

AI Gateway now includes Guardrails, to help you monitor your AI apps for harmful or inappropriate content and deploy safely.

Within the AI Gateway settings, you can configure:

• Guardrails: Enable or disable content moderation as needed.
• Evaluation scope: Select whether to moderate user prompts, model responses, or both.
• Hazard categories: Specify which categories to monitor and determine whether detected inappropriate content should be blocked or flagged.

Guardrails in AI Gateway

Learn more in the blog ↗︎ or our documentation.

We've released the Agents SDK ↗︎, a package and set of tools that help you build and ship AI Agents.

You can get up and running with a chat-based AI Agent ↗︎ (and deploy it to Workers) that uses the Agents SDK, tool calling, and state syncing with a React-based front-end by running the following command:

npm create cloudflare@latest agents-starter -- --template="cloudflare/agents-starter"
# open up README.md and follow the instructions

You can also add an Agent to any existing Workers application by installing the agents package directly

npm i agents

... and then define your first Agent:

import { Agent } from "agents";

export class YourAgent extends Agent<Env> {
	// Build it out
	// Access state on this.state or query the Agent's database via this.sql
	// Handle WebSocket events with onConnect and onMessage
	// Run tasks on a schedule with this.schedule
	// Call AI models
	// ... and/or call other Agents.
}

Head over to the Agents documentation to learn more about the Agents SDK, the SDK APIs, as well as how to test and deploying agents to production.

Workers AI now supports structured JSON outputs with JSON mode, which allows you to request a structured output response when interacting with AI models.

This makes it much easier to retrieve structured data from your AI models, and avoids the (error prone!) need to parse large unstructured text responses to extract your data.

JSON mode in Workers AI is compatible with the OpenAI SDK's structured outputs ↗︎ response_format API, which can be used directly in a Worker:

import { OpenAI } from "openai";

// Define your JSON schema for a calendar event
const CalendarEventSchema = {
	type: "object",
	properties: {
		name: { type: "string" },
		date: { type: "string" },
		participants: { type: "array", items: { type: "string" } },
	},
	required: ["name", "date", "participants"],
};

export default {
	async fetch(request, env) {
		const client = new OpenAI({
			apiKey: env.OPENAI_API_KEY,
			// Optional: use AI Gateway to bring logs, evals & caching to your AI requests
			// https://developers.cloudflare.com/ai-gateway/usage/providers/openai/
			// baseUrl: "https://gateway.ai.cloudflare.com/v1/{account_id}/{gateway_id}/openai"
		});

		const response = await client.chat.completions.create({
			model: "gpt-4o-2024-08-06",
			messages: [
				{ role: "system", content: "Extract the event information." },
				{
					role: "user", …

You can now interact with the Images API directly in your Worker.

This allows more fine-grained control over transformation request flows and cache behavior. For example, you can resize, manipulate, and overlay images without requiring them to be accessible through a URL.

The Images binding can be configured in the Cloudflare dashboard for your Worker or in the Wrangler configuration file in your project's directory:

{
	"images": {
		"binding": "IMAGES", // i.e. available in your Worker on env.IMAGES
	},
}

[images]
binding = "IMAGES"

Within your Worker code, you can interact with this binding by using env.IMAGES.

Here's how you can rotate, resize, and blur an image, then output the image as AVIF:

const info = await env.IMAGES.info(stream);
// stream contains a valid image, and width/height is available on the info object

const response = (
	await env.IMAGES.input(stream)
		.transform({ rotate: 90 })
		.transform({ width: 128 })
		.transform({ blur: 20 })
		.output({ format: "image/avif" })
).response();

return response;

For more information, refer to Images Bindings.

Zaraz at zone level to Tag management at account level

Previously, you could only configure Zaraz by going to each individual zone under your Cloudflare account. Now, if you’d like to get started with Zaraz or manage your existing configuration, you can navigate to the Tag Management ↗︎ section on the Cloudflare dashboard – this will make it easier to compare and configure the same settings across multiple zones.

These changes will not alter any existing configuration or entitlements for zones you already have Zaraz enabled on. If you’d like to edit existing configurations, you can go to the Tag Setup ↗︎ section of the dashboard, and select the zone you'd like to edit.

Workers for Platforms ↗︎ is an architecture wherein a centralized dispatch Worker processes incoming requests and routes them to isolated sub-Workers, called User Workers.

Workers for Platforms Requests

Previously, when a new User Worker was uploaded, there was a short delay before it became available for dispatch. This meant that even though an API request could return a 200 OK response, the script might not yet be ready to handle requests, causing unexpected failures for platforms that immediately dispatch to new Workers.

With this update, first-time uploads of User Workers are now deployed synchronously. A 200 OK response guarantees the script is fully provisioned and ready to handle traffic immediately, ensuring more predictable deployments and reducing errors.

We've updated the Workers AI pricing to include the latest models and how model usage maps to Neurons.

• Each model's core input format(s) (tokens, audio seconds, images, etc) now include mappings to Neurons, making it easier to understand how your included Neuron volume is consumed and how you are charged at scale
• Per-model pricing, instead of the previous bucket approach, allows us to be more flexible on how models are charged based on their size, performance and capabilities. As we optimize each model, we can then pass on savings for that model.
• You will still only pay for what you consume: Workers AI inference is serverless, and not billed by the hour.

Going forward, models will be launched with their associated Neuron costs, and we'll be updating the Workers AI dashboard and API to reflect consumption in both raw units and Neurons. Visit the Workers AI pricing page to learn more about Workers AI pricing.

Auto-fixing Workers Name in Git Repo

Small misconfigurations shouldn’t break your deployments. Cloudflare is introducing automatic error detection and fixes in Workers Builds, identifying common issues in your wrangler.toml or wrangler.jsonc and proactively offering fixes, so you spend less time debugging and more time shipping.

Here's how it works:

1. Before running your build, Cloudflare checks your Worker's Wrangler configuration file (wrangler.toml or wrangler.jsonc) for common errors.
2. Once you submit a build, if Cloudflare finds an error it can fix, it will submit a pull request to your repository that fixes it.
3. Once you merge this pull request, Cloudflare will run another build.

We're starting with fixing name mismatches between your Wrangler file and the Cloudflare dashboard, a top cause of build failures.

This is just the beginning, we want your feedback on what other errors we should catch and fix next. Let us know in the Cloudflare Developers Discord, #workers-and-pages-feature-suggestions ↗︎.