By the documentation "Currently, all images must use registry.cloudflare.com, which is the default r

By the documentation "Currently, all images must use registry.cloudflare.com, which is the default registry for Wrangler." (https://developers.cloudflare.com/containers/image-management/#using-existing-images) so you have to pull & push to cloudflare registry

Cloudflare Docs

Image Management

When running wrangler deploy, if you set the image attribute in you Wrangler configuration
file to a path, wrangler will build your container image locally using Docker, then push it to a registry run by Cloudflare.
This registry is integrated with your Cloudflare account and is backed by R2. All authentication is handled automatically by
Cloudf...

Mmcanaleta By the documentation "Currently, all images must use registry.cloudflare.com, wh...

bro14•9/19/25, 1:21 PM

ahh i see, thank you for responding

kian•9/19/25, 1:24 PM

Yeah - currently pull it locally and push it up to our registry.

kian•9/19/25, 1:24 PM

External registry support is being worked on as mentioned in the docs aside - basically pullthrough so we do the pull + push for you.

Kkian <https://github.com/cloudflare/templates/tree/main/containers-template> is proba...

Steps•9/19/25, 6:22 PM

That is the "most simple"? It's pretty complex.

To be honest, it looks more like a testbed than a minimalistic "get you started" template.

Steps•9/19/25, 9:12 PM

Ok, I made the simple example I was looking for myself after some trial and error.

https://github.com/StefanOltmann/kotlin-cloudflare-containers-sample

Steps•9/19/25, 9:19 PM

Is Cloudflare open to contributions?
I could send that as a PR to https://github.com/cloudflare/templates/tree/main ...

SSteps Is Cloudflare open to contributions? I could send that as a PR to https://github...

blyedev•9/20/25, 1:46 PM

As far as I remember their contribution guide said they very much are but have certain requirements.

blyedev•9/20/25, 1:47 PM

Ngl I'd love if they had like a keycloak deployment in templates, would be incredible to just deploy sso with minimal config

Steps•9/21/25, 8:11 PM

What can cause

Container suddenly disconnected, try again

Container suddenly disconnected, try again

after ~10s ? Is that a response timeout?

Steps•9/21/25, 8:39 PM

On the highest instance type my POST request is successful in 100 ms, but the response is still HTTP 500

Steps•9/21/25, 8:40 PM

It has the structure like here: https://github.com/StefanOltmann/kotlin-cloudflare-containers-sample/

Just with a POST instead of a GET.

Does that make a difference?

CodingCoop | Co-Founder Nullshot•9/22/25, 10:13 AM

I'm running some applications simialr to the sandbox sdk. To get an nodejs app started in dev mode, it's taking ~3 minutes which isn't bad, but there are CPU intensive operations when dynamically downloading code in a sandbox. I think .5 CPU is not enough and ideally I'd want to burst up to 2 vCPU if not dedicated.

Sent my feedback, but I think 2 vCPU + 8gb Memory is where my sweet spot will be 16 Gb memory for more intensive apps like games and a GPU for all my use cases which I assume is far out.

CodingCoop | Co-Founder Nullshot•9/22/25, 10:14 AM

https://github.com/cloudflare/sandbox-sdk <== for those who haven't found this gem

GitHub

GitHub - cloudflare/sandbox-sdk: Run sandboxed code environments on...

Run sandboxed code environments on Cloudflare's edge network - cloudflare/sandbox-sdk

Rui Hayashi•9/22/25, 1:06 PM

How can I set a container directly through the Cloudflare API? Is this documented somewhere? Having a look at wrangler's code, it seems there is a /applications endpoint (https://github.com/cloudflare/workers-sdk/blob/main/packages/containers-shared/src/client/services/ApplicationsService.ts#L44), but when I try to call it I get a "No route for that URI" error.

GitHub

workers-sdk/packages/containers-shared/src/client/services/Applicat...

Home to Wrangler, the CLI for Cloudflare Workers® - cloudflare/workers-sdk

workers-sdk/packages/containers-shared/src/client/services/Applicat...

RRui Hayashi How can I set a container directly through the Cloudflare API? Is this documente...

John Spurlock•9/22/25, 1:16 PM

all of those endpoints are prefixed by /containers/containers

JJohn Spurlock all of those endpoints are prefixed by `/containers`

Rui Hayashi•9/22/25, 1:29 PM

that worked, thanks for the help (do you know whether this is documented somewhere?)

RRui Hayashi that worked, thanks for the help (do you know whether this is documented somewhe...

John Spurlock•9/22/25, 1:40 PM

I don't believe it is, although I wish it was. In case it helps, here is a client api I wrote against it - same as you, just based on poking through wrangler

https://github.com/skymethod/denoflare/blob/f46183514877db55d1fff21a9eb0055fa09ae827/common/cloudflare_api.ts#L2586

Steps•9/22/25, 3:42 PM

For Cloudflare Containers the included usage is 375 vCPU-minutes/month ...
That means the small "dev" instance with 1/16 vCPU can run for 6000 minutes/month, which are roughly 4 days. Is that math correct?

If I set "sleepAfter" to "0" this bascially means that every call to the container will be a 2-3 second cold start, right?

My service gets a call every 20 seconds. So if I set the timeout to 30 seconds, it will be active all the time and burn through the quota with reaching the limit after 4 days... is that correct?

Or will it still be considerably fast when sleeping?

An AWS lambda has a nasty cold start of 2-3 seconds, too, but after that it's "warm" for about 10 to 15 minutes... But I only need to pay the actual usage time, not the time it's idling.

Did I get that right about the difference between a AWS Lambda and an Cloudflare Container?

Vvilvei AWS Lambda is a function service, that can be called using http via their apigat...

pandalambda2•9/23/25, 8:15 AM

the OP is probably using lambda layers then architecturally its almost identical

Vvilvei AWS Lambda is a function service, that can be called using http via their apigat...

Steps•9/23/25, 6:48 PM

Yes, AWS API gateway is pricy. I use the HTTP Function URLs - they are free.

Vvilvei If you know you are receiving a call every 20 seconds, then you could create Dur...

Steps•9/23/25, 6:50 PM

My question is not so much about how to avoid the cold start... it's about the billable duration.

The difference is that idle time on Containers cost while the time an AWS lambda stays warm after invocation doesn't, right?

If I set set the cointainer sleep to 0, will every call be a cold start or will it stay warm for a while?

SSteps My question is not so much about how to avoid the cold start... it's about the b...

gruntlord6•9/23/25, 11:45 PM

thats more comparable to a durable object then a container

pandalambda2•9/24/25, 1:33 AM

So the new about capnweb dropped, and it's powering wrangler local<>remote services in dev mode, i.e. it can communicate with Cloudflare services remotely and this is powered by capnweb protocol, so things like kv, worker bindings, queues etc.. are no longer restricted to workers, so I guess in theory if one digs into the source code for wrangler, we could use the same code to allow direct communicate from containers. My question is are you planning to drop a few SDKs for this - node initially, java, dotnet, go, rust? And secondly is this on the short term horizon perhaps this birthday week?

pandalambda2•9/24/25, 1:34 AM

ref: https://blog.cloudflare.com/capnweb-javascript-rpc-library/#try-it-out (the bottom bit about remote bindings)...

The Cloudflare Blog

Cap'n Web: A new RPC system for browsers and web servers

Cap'n Web is a new open source, JavaScript-native RPC protocol for use in browsers and web servers. It provides the expressive power of Cap'n Proto, but with no schemas and no boilerplate.

pandalambda2•9/24/25, 1:35 AM

it would really nice to not have to use the cripppled front-door rest HTTP apis for cloudflare services from containers, fingers crossed for more info

pandalambda2•9/24/25, 1:39 AM

and if capnweb rpc trafifc to CF services did not incur container egress fees...

pandalambda2•9/24/25, 4:00 AM

@kian | Containers can you raise this internally - https://www.cloudflare.com/ips/ is out of date. for example I am making outbound container egress from 104.28.154.x currently

IP Ranges | Cloudflare

This page is intended to be the definitive source of Cloudflare’s current IP ranges.

pandalambda2•9/24/25, 4:00 AM

does not intersect with any of those ipv4 ranges

pandalambda2•9/24/25, 4:01 AM

afaik

pandalambda2•9/24/25, 4:03 AM

NetRange: 104.16.0.0 - 104.31.255.255
CIDR: 104.16.0.0/12

pandalambda2•9/24/25, 4:03 AM

its listed as a /13

pandalambda2•9/24/25, 4:04 AM

I'm hoping this is only used for container egress, as that a pretty huge oversight if these are proxy ips as well (our iac fetch this ipv4 file to allow cf <-> origin traffic)

Ppandalambda2 @kian | Containers can you raise this internally - https://www.cloudflare.com/ip...

kian•9/24/25, 4:33 AM

It's actually expected that Containers don't egress from those IPs.

kian•9/24/25, 4:34 AM

There isn't currently any published IPs that you can use to lock down egress from Containers alone.

pandalambda2•9/24/25, 4:50 AM

thanks, is a stable range of outbound IPs expected for GA?

Ggruntlord6 thats more comparable to a durable object then a container

Steps•9/24/25, 5:19 AM

I understand that Containers are backed by Durables…

However, my question doesn’t matter anymore as the pricing on Containers that also includes Durables and Workers according to the docs, seems pretty confusing. There are too many parts to understand the total costs.

Given my recent experiences with R2 and the strict „no refunds“ policy this could be very well the next thing I mess up and end up with unexpected/high bills. So I decided that I will stick strictly to workers for everything I can do with them and for everything else they need to call an AWS lambda.

pandalambda2•9/24/25, 5:25 AM

@Steps watching with interest but I agree far too many unknowns across the whole board, not just pricing. In april they said https://blog.cloudflare.com/cloudflare-containers-coming-2025/ "We'll be working out the details between now and the beta, and will be launching with clear, transparent pricing across all dimensions so you know where you stand" <- . well beta came and this couldn't be further from the truth, clear as mud

currently reading https://docs.aws.amazon.com/lambda/latest/dg/images-create.html#images-ric

The Cloudflare Blog

Simple, scalable, and global: Containers are coming to Cloudflare W...

Cloudflare Containers are coming this June. Run new types of workloads on our network with an experience that is simple, scalable, global and deeply integrated with Workers.

Steps•9/24/25, 5:42 AM

On AWS I used the Java images in the past and for the better cold start time I’m moving to native images using Kotlin/Native.

Yes, it’s not only the pricing, but mostly. The other thing (as said above) is that they can’t idle without cost. That’s the deal breaker for me, too.

I’d like to pay only for the time the Container actual does something purely based on the time it takes. Having different prices based on instance size is fine, of course. Paying for Durables extra seems unnecessarily.

pandalambda2•9/24/25, 5:55 AM

Oh that's interesting, I didn't realize Kotlin/Native was ready for server-side work, Ktor is there now i see, but you've got no r2dc or jdbc? I guess if you've got a http client though you can talk to all of aws rest http apis including dynamodb, but I imagine you have zero sdks so you're hand rolling your own high level client code for the dependencies?

SSteps I understand that Containers are backed by Durables… 🤔 However, my question do...

gruntlord6•9/24/25, 5:56 AM

I think thats probably a good call here, its very easy to lose track of containers given how early they are in dev at this stage

gruntlord6•9/24/25, 5:57 AM

personally I decided unless its something that needs to live in cloudflare its honestly easier to have an actual vps running a container vs using cloudflare containers, especially at this stage

gruntlord6•9/24/25, 5:57 AM

its certainly cheaper and more performant, although less scalable

pandalambda2•9/24/25, 5:59 AM

https://dokku.com/ on a VM for now works, but we may go AWS lambda or ecs fargate in meantime, see what comes out in rest of developer week from CF

Dokku - The smallest PaaS implementation you've ever seen

pandalambda2•9/24/25, 6:00 AM

birthday week *

Ppandalambda2 Oh that's interesting, I didn't realize Kotlin/Native was ready for server-side ...

Steps•9/24/25, 6:02 AM

AWS is migrating their Kotlin SDK to Native. I expect that to be usable in the near future.
Right now I use APIs via HTTP if I need to.
Here is a small project I build: https://github.com/StefanOltmann/steam-login-helper
it doesn’t use AWS APIs. I still need to figure out how to use them, but that’s the next thing I’m going to do.

pandalambda2•9/24/25, 6:02 AM

>AWS is migrating their Kotlin SDK to Native

oh wow, that is game changing..

pandalambda2•9/24/25, 6:02 AM

will take a look at that repo, thanks

Ashish Rawat•9/24/25, 6:10 AM

Why containers pricing look so costly considering it also require durable objects. I compared this with cloud run (instance based billing):
- vCPU :
GCP : $0.000018/sec vs $0.000020/sec (CF)
- Memory
GCP : $0.000002/sec vs $0.0000025/sec (CF)

Plus cloudflare containers run on durable objects + workers which is another extra cost. So overall, this looks like atleast 2x costlier.

I'm already using workers and my use case with containers is to host mongodb atlas with small container (never sleep) for fast requests and mongodb in-built connection pooling (since mongodb require durable object for connection pooling).

By the documentation "Currently, all images must use registry.cloudflare.com, which is the default r

Similar Threads

Similar Threads

Similar Threads