Anyone else getting 503 errors when invoking from a worker binding? - Cloudflare Developers

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gegi

G

gegi•10/22/25, 1:28 PM

Hello, can I cancel Browser Rendering calls with an abort signal?

welz

Wwelz Anyone else getting 503 errors when invoking from a worker binding?

welz

W

welzOP•10/22/25, 2:48 PM

and again...

welz

Wwelz and again...

Kathy

K

Kathy•10/22/25, 5:41 PM

you're right we had an incident yesterday and today. it's our top priority to get to the bottom of. major apologies

Jahvon

JJahvon I have another question related to the Stagehand integration - is there a way to...

Eric

E

Eric•10/22/25, 9:12 PM

@JDoc I've had this happen a ton locally, but it seems better in production. Did you experience that Playwright(-MCP), too? (I have)

ancs21

A

ancs21•10/23/25, 10:21 AM

The issue concerns the parser start time.

ancs21

Aancs21 The issue concerns the parser start time.

Eric

E

Eric•10/23/25, 9:45 PM

@Rui Figueira said in this issue that he'll report that to the team.

Eric

E

Eric•10/23/25, 9:51 PM

This may be more about #agents , but I'm surprised (or terrible at investigation) that https://github.com/cloudflare/playwright-mcp isn't

acquire

acquire

ing a dedicated browser for each agent session.

I would've expected it to internally do something like

routeAgentRequest

routeAgentRequest

. I'm afraid that my agents are all referencing the same

env.BROWSER

env.BROWSER

(but separate contexts)

NextMerge

N

NextMerge•10/27/25, 1:51 AM

Had a question regarding the Browser Rendering’s Rest API: In the docs it mentions that if a request is rate-limited, it’ll return a “Retry-After” header with the number of seconds until you can try again: https://developers.cloudflare.com/browser-rendering/platform/limits/#error-429-too-many-requests

From testing the api in curl it doesn’t seem to be including this header though. Even using the sample JS code shown ends up with a null retry count. When I was testing it last week I feel like it was including this header, so is this related to the outage that happened?

aem

A

aem•10/30/25, 5:25 PM

Hiya, we're trying to port our PDF rendering from DocRaptor to the Browser Rendering API, but it seems like loading custom fonts via the REST API isn't working, and we'd like to avoid spinning up a worker just for this purpose. Is there a way to allow loading fonts via

style

style

tags via the REST API that I'm not seeing or is that not an option? If not, is it on the roadmap?

aem

Aaem Hiya, we're trying to port our PDF rendering from DocRaptor to the Browser Rende...

welz

W

welzOP•10/31/25, 6:14 AM

I've loaded custom fonts from Google fonts - but invoking via Worker, might be different via API

welz

Wwelz I've loaded custom fonts from Google fonts - but invoking via Worker, might be d...

aem

A

aem•10/31/25, 2:46 PM

Yeah unfortunately we can't use Google fonts, we've got a custom font we self-host on our CDN. I know we can do this with a Worker, but we'd really rather not do that - our main app is hosted on GCP right now and building a GCP <> CF auth integration is more effort than it's worth to get fast PDF rendering

Hassan

H

Hassan•11/1/25, 8:52 AM

Does anyone else have this issue?
curl -X 'POST' 'https://api.cloudflare.com/client/v4/accounts/9357fcd5fdd482d8ff83604451aad279/browser-rendering/markdown' \
-H 'Content-Type: application/json' \
-H 'Authorization: Bearer INkf8LWxNWrE96x4Z-zDCiAgoxMG6KfUuYvUAvyg' \
-d '{
"url": "https://www.czone.com.pk/graphic-cards-pakistan-ppt.154.aspx"
}'
{"success":true,"result":"# !Icon for www.czone.com.pkwww.czone.com.pk\n\nVerifying you are human. This may take a few seconds.
\n\nwww.czone.com.pk needs to review the security of your connection before proceeding.\n\nVerification successful\n\nWaiting for www.czone.com.pk to respond...\n\nRay ID:

997a23bf1a81339e

997a23bf1a81339e

\n\nPerforman
ce & security by Cloudflare"}

I'm simply trying to get prices from a website and get blocked by cloudflare itself. So its not possible to use cloudflare browser rendering for website that use cloudflare?

Celestial Rose

C

Celestial Rose•11/3/25, 10:45 AM

hey there ! using Stagehand in Browser Rendering I am wondering how to reuse sessions the same way its currently possible in Puppeteer as per these documentation : https://developers.cloudflare.com/browser-rendering/workers-bindings/reuse-sessions/
I am not sure I cant get to the browser sesh there and would love to not use DO for that

Cloudflare Docs

The best way to improve the performance of your browser rendering Worker is to reuse sessions. One way to do that is via Durable Objects, which allows you to keep a long running connection from a Worker to a browser. Another way is to keep the browser open after you've finished with it, and connect to that session each time you have a new request.

Celestial Rose

CCelestial Rose hey there ! using Stagehand in Browser Rendering I am wondering how to reuse ses...

Celestial Rose

C

Celestial Rose•11/3/25, 10:46 AM

maybe here ? https://docs.stagehand.dev/v3/best-practices/cost-optimization#3-optimize-browser-sessions

Stagehand Docs

Cost Optimization - 🤘 Stagehand

Minimize costs while maintaining automation performance

Hassan

HHassan Does anyone else have this issue? curl -X 'POST' 'https://api.cloudflare.com/cli...

Kathy

K

Kathy•11/4/25, 1:59 AM

Whether browser rendering can access a site or not depends on the settings of that site. So seems the site you are trying to use is blocking bots

Browser rendering always identifies itself as a bot, so if the site owner chooses to block all bots, then browser rendering will be blocked too.

if it's a site you own, you can create a rule to allow for browser rendering
https://developers.cloudflare.com/browser-rendering/faq/#will-browser-rendering-bypass-cloudflares-bot-protection

Cloudflare Docs

Below you will find answers to our most commonly asked questions about Browser Rendering.

divby0

D

divby0•11/4/25, 8:22 AM

When trying to launch the browser inside a worker, it works 100% of the time. When launching from a workflow, it fails about half of the time with this error:

workerd/jsg/setup.c++:38: fatal: V8 fatal error; location = :0; message = Missing deoptimization information for OptimizedJSFrame::Summarize.

aem

Aaem Yeah unfortunately we can't use Google fonts, we've got a custom font we self-ho...

Kathy

K

Kathy•11/4/25, 11:44 PM

you can

addStyleTag

addStyleTag

to customize. see example here https://developers.cloudflare.com/browser-rendering/rest-api/screenshot-endpoint/#customize-css-and-embed-custom-javascript

Cloudflare Docs

/screenshot - Capture screenshot

The /screenshot endpoint renders the webpage by processing its HTML and JavaScript, then captures a screenshot of the fully rendered page.

Celestial Rose

CCelestial Rose hey there ! using Stagehand in Browser Rendering I am wondering how to reuse ses...

Kathy

K

Kathy•11/4/25, 11:46 PM

checked with the team:

They can use

keep_alive

keep_alive

, eg

const browser = await puppeteer.launch(env.MYBROWSER, { keep_alive: 600000 });

const browser = await puppeteer.launch(env.MYBROWSER, { keep_alive: 600000 });

to keep the browser alive for 10 minutes, and then, in order to get a valid

sessionId

sessionId

, they need to call

https://developers.cloudflare.com/browser-rendering/platform/puppeteer/#list-open-sessions

https://developers.cloudflare.com/browser-rendering/platform/puppeteer/#list-open-sessions

.

Full example here https://developers.cloudflare.com/browser-rendering/workers-bindings/reuse-sessions/#4-code

Cloudflare Docs

The best way to improve the performance of your browser rendering Worker is to reuse sessions. One way to do that is via Durable Objects, which allows you to keep a long running connection from a Worker to a browser. Another way is to keep the browser open after you've finished with it, and connect to that session each time you have a new request.

Kathy

KKathy checked with the team: They can use `keep_alive` , eg `const browser = await pu...

Celestial Rose

C

Celestial Rose•11/4/25, 11:48 PM

Hey! Thanks for your reply, I have found this link already, but does this work for stagehand ? This seems to only work for puppeteer; I literally posted this link in my OG post haha

Vikash

V

Vikash•11/5/25, 4:29 AM

The /snapshot API documentation is outdated? or the response has been changed, I don't see

status

status

in response, instead the response just display

success: true/false

success: true/false

, while I was expecting the response status: 2xx, 4xx etc retuned by given URL. As it always says success: true, even for 404 link as well

Vikash

V

Vikash•11/5/25, 4:32 AM

For example, I passed a bad link in url - which return 404 on browser, but there are no way to find out it retuned 404 using the /snapshot API. Which enforce me to send 2 requests (one for status, another for snapshot)

Nathan

N

Nathan•11/5/25, 7:28 PM

Have anyone ran into an issue while trying to download a file via Playwright

Download.createReadStream()

Download.createReadStream()

API?

The readable has no data in it. Doesn't throw an error, but just 0 chunks.

Kathy

KKathy you can `addStyleTag` to customize. see example here https://developers.cloudfla...

aem

A

aem•11/7/25, 2:37 AM

Yes we've tried both

addStyleTag

addStyleTag

as well as an embedded stylesheet in the HTML with

font

font

as an allowed resource type, neither work

Mazin

M

Mazin•11/9/25, 8:12 PM

i made a worker for browser rendering and deployed it, the first request i made i got this error, why?

Error: Unable to create new browser: code: 429: message: Rate limit exceeded

Stack trace:
Error: Unable to create new browser: code: 429: message: Rate limit exceeded
at PuppeteerWorkers.acquire (index.js:18328:13)
at async PuppeteerWorkers.launch (index.js:18238:22)
at async Object.fetch (index.js:19976:23)

Mazin

M

Mazin•11/9/25, 8:36 PM

anyone?

Masquerades

M

Masquerades•11/10/25, 12:48 AM

Hey team, what's going on here?

I'm trying to run the documented code snippet from https://developers.cloudflare.com/browser-rendering/rest-api/json-endpoint/#using-a-custom-model-byo-api-key

Simply replacing the ai provider from anthropic to google-ai-studio/gemini-2.5-flash, or google-ai-studio/gemini-flash-latest. I get the error {"success":false,"errors":[{"message":"AI error: undefined: undefined"}]}%. Looks like someone else is having the problem too: https://community.cloudflare.com/t/browser-rendering-json-with-custom-ai/854912

Am I missing something here, or is the snippet in the documentation incorrect?

zapalona_swieczka

Z

zapalona_swieczka•11/11/25, 7:58 AM

any chance anyone is making screenshot of an element? screenshot of playwright page works excelent, but when I try to run locator to find some element and then run screenshot - timeouts, tried like 5-6 different methods to get element

zapalona_swieczka

Z

zapalona_swieczka•11/12/25, 10:54 AM

I wonder how much of time of browser rendering cpu time of workers is counted. Since browser rendering is paid, I hope majority of time spent on that will not be billed as worker cpu-time?

Mazin

MMazin i made a worker for browser rendering and deployed it, the first request i made ...

mtnrunner

M

mtnrunner•11/12/25, 7:31 PM

did you find a resolution for this? same thing with me

mtnrunner

M

mtnrunner•11/12/25, 8:31 PM

Alas, i assume there is a bug

  {
    "sessionId": "31ab6f51-4628-41e0-bf91-477cb48fda4a",
    "startTime": 1762969852952,
    "endTime": 1762969856860,
    "closeReason": 12,
    "closeReasonText": "UsedBrowserTimeLimitExceeded"
  }

  {
    "sessionId": "31ab6f51-4628-41e0-bf91-477cb48fda4a",
    "startTime": 1762969852952,
    "endTime": 1762969856860,
    "closeReason": 12,
    "closeReasonText": "UsedBrowserTimeLimitExceeded"
  }

that's about 4 seconds and i see in the UI it looks like

31ab6f51-4628-41e0-bf91-477cb48fda4a
Dec 31, 1969 5:00:00 PM
Nov 12, 2025 10:50:56 AM

31ab6f51-4628-41e0-bf91-477cb48fda4a
Dec 31, 1969 5:00:00 PM
Nov 12, 2025 10:50:56 AM

mtnrunner

Mmtnrunner Alas, i assume there is a bug ``` { "sessionId": "31ab6f51-4628-41e0-bf91-...

Kathy

K

Kathy•11/12/25, 9:04 PM

Are you on the Workers Paid plan? or Workers Free plan?

Users on Workers Free are limited to 10 minutes a day https://developers.cloudflare.com/browser-rendering/limits/#workers-free

Cloudflare Docs

Learn about the limits associated with Browser Rendering.

mtnrunner

Mmtnrunner Alas, i assume there is a bug ``` { "sessionId": "31ab6f51-4628-41e0-bf91-...

Kathy

K

Kathy•11/12/25, 9:05 PM

timestart being the wrong year is a bug - on our list to fix

Kathy

KKathy timestart being the wrong year is a bug - on our list to fix

mtnrunner

M

mtnrunner•11/12/25, 9:55 PM

awesome! its the free plan, am planning to upgrade but just wanted to test this out - this is the only request i made today and everything after said it was 429'd - so 4 seconds == hit my limit for the day based on the logs i see

mtnrunner

Mmtnrunner awesome! its the free plan, am planning to upgrade but just wanted to test this ...

Kathy

K

Kathy•11/13/25, 12:41 AM

can you dm me your account id?

odd you weren't able to use 10 minutes

Kathy

K

Kathy•11/13/25, 8:39 PM

Hi y'all!

Browser Rendering is due for a dashboard update

What would you like to see added to the dashboard?

Please feel free to chime in here on chat or we can discuss live! https://calendar.app.google/Xe4EWuvaAVvehDPC6

Browser Rendering Chat - Kathy Liao

mtnrunner

Mmtnrunner awesome! its the free plan, am planning to upgrade but just wanted to test this ...

Kathy

K

Kathy•11/14/25, 5:06 PM

this is fixed! thanks for raising~

Masquerades

MMasquerades Hey team, what's going on here? I'm trying to run the documented code snippet f...

TheCrazyBob

T

TheCrazyBob•11/16/25, 1:05 PM

@Kathy I am having the same issue on my end. I can see another user reporting this as well: https://community.cloudflare.com/t/browser-rendering-json-with-custom-ai/854912

1984 Ford Laser

1

1984 Ford Laser•11/18/25, 6:16 AM

Have tried using the Browser Rendering REST API, but it isn't working. The Workers API binding works fine, and I have created a new API token with Browser Rendering Edit perms. I can confirm that using a different token gives an auth error. Doesn't work with either a URL or HTML body param

1984 Ford Laser

1

1984 Ford Laser•11/18/25, 6:17 AM

Also, in the Workers binding, is it normal for it to take 7-10 seconds to get a screenshot response for a very simple HTML page hosted on CF?

Masquerades

MMasquerades Hey team, what's going on here? I'm trying to run the documented code snippet f...

TheCrazyBob

T

TheCrazyBob•11/18/25, 10:32 AM

Were you able to find a solution? The custom AI provider feature doesn't work

arnaseef

A

arnaseef•11/20/25, 6:08 PM

https://community.cloudflare.com/t/browser-rendering-json-with-custom-ai/854912/2

@Kathy

Kathy

K

Kathy•11/21/25, 6:21 PM

json endpoint bugs have been fixed for both gemini and openai! thanks for reporting @arnaseef , @TheCrazyBob , @Masquerades

Kathy

KKathy json endpoint bugs have been fixed for both gemini and openai! thanks for report...

TheCrazyBob

T

TheCrazyBob•11/22/25, 3:37 PM

I can't get it to work with openai's models. Haven't tried gemini yet. I always get the following error:

{
  "success": false,
  "errors": [
    {
      "message": "Unable to form JSON based on user prompt and/or webpage text. Please try with a different prompt try passing a response_format."
    }
  ]
}

{
  "success": false,
  "errors": [
    {
      "message": "Unable to form JSON based on user prompt and/or webpage text. Please try with a different prompt try passing a response_format."
    }
  ]
}

hunterleung.

H

hunterleung.•11/27/25, 5:02 PM

Hi, could anybody give a sample usage about the snapshot API (https://developers.cloudflare.com/api/python/resources/browser_rendering/subresources/snapshot/methods/create/) ?
I wanna add the "full_page" and "type" to request, but I always get a error:

I have tried these 2 request body ,but not work either:

{
    "url": "https://www.bbc.com/",
    "screenshot_options":  {"full_page" : true , "type":"webp" }
  }

{
    "url": "https://www.bbc.com/",
    "screenshot_options":  {"full_page" : true , "type":"webp" }
  }

{
    "url": "https://www.bbc.com/",
    "full_page" : true , 
    "type":"webp" }
  }

{
    "url": "https://www.bbc.com/",
    "full_page" : true , 
    "type":"webp" }
  }

I got this error:

{
    "errors": [
        {
            "code": "unrecognized_keys",
            "keys": [
                "screenshot_options"
            ],
            "path": [
                "body"
            ],
            "message": "Unrecognized key(s) in object: 'screenshot_options'"
        }
    ],
    "success": false,
    "result": {}
}

{
    "errors": [
        {
            "code": "unrecognized_keys",
            "keys": [
                "screenshot_options"
            ],
            "path": [
                "body"
            ],
            "message": "Unrecognized key(s) in object: 'screenshot_options'"
        }
    ],
    "success": false,
    "result": {}
}

How should I fix it ? Thanks

Cloudflare API | Browser Rendering › Snapshot › create

Interact with Cloudflare's products and services via the Cloudflare API

hunterleung.

H

hunterleung.•11/28/25, 3:31 AM

@Kathy hi,Kathy , could you help me ?

hunterleung.

Hhunterleung.Hi, could anybody give a sample usage about the snapshot API (https://developer...

Gibbeth

G

Gibbeth•11/28/25, 3:35 AM

you're running POST @ /accounts/{account_id}/browser-rendering/snapshot right?

Gibbeth

G

Gibbeth•11/28/25, 3:36 AM

based on the docs ur i think the first example should be the functioning one

  {
    "sessionId": "31ab6f51-4628-41e0-bf91-477cb48fda4a",
    "startTime": 1762969852952,
    "endTime": 1762969856860,
    "closeReason": 12,
    "closeReasonText": "UsedBrowserTimeLimitExceeded"
  }

  {
    "sessionId": "31ab6f51-4628-41e0-bf91-477cb48fda4a",
    "startTime": 1762969852952,
    "endTime": 1762969856860,
    "closeReason": 12,
    "closeReasonText": "UsedBrowserTimeLimitExceeded"
  }

{
    "errors": [
        {
            "code": "unrecognized_keys",
            "keys": [
                "screenshot_options"
            ],
            "path": [
                "body"
            ],
            "message": "Unrecognized key(s) in object: 'screenshot_options'"
        }
    ],
    "success": false,
    "result": {}
}

{
    "errors": [
        {
            "code": "unrecognized_keys",
            "keys": [
                "screenshot_options"
            ],
            "path": [
                "body"
            ],
            "message": "Unrecognized key(s) in object: 'screenshot_options'"
        }
    ],
    "success": false,
    "result": {}
}

{
  "success": false,
  "errors": [
    {
      "message": "Unable to form JSON based on user prompt and/or webpage text. Please try with a different prompt try passing a response_format."
    }
  ]
}

{
  "success": false,
  "errors": [
    {
      "message": "Unable to form JSON based on user prompt and/or webpage text. Please try with a different prompt try passing a response_format."
    }
  ]
}