Cloudflare_workers_custom_domain returns 500 Internal Server Error (code 10013) from /workers/domains

[ffrants]

Confirmation

• This is a bug with an existing resource and is not a feature request or enhancement. Feature requests should be submitted with Cloudflare Support or your account team.
• I have searched the issue tracker and my issue isn't already found.
• I have replicated my issue using the latest version of the provider and it is still present.

Terraform and Cloudflare provider version

Terraform v1.13.5

Cloudflare Terraform provider:
registry.terraform.io/cloudflare/cloudflare v5.13.0

Operating system:
macOS 15.0 (Sonoma)

Authentication:
API token with:

• Zone: Zone:Read, DNS:Edit
• Account: Workers Scripts:Edit, Workers Builds Configuration:Edit

Affected resource(s)

cloudflare_workers_custom_domain
cloudflare_worker

Terraform configuration files

locals {
  webshop_worker_name = "webshop-frontend-${var.env_id}"
  webshop_hostname    = "shop.${var.env_id}.${var.root_dev_domain}"
}

locals {
  cloudflare_account_id = var.cloudflare_account_id
}

data "cloudflare_zone" "root" {
  filter = {
    name = var.root_dev_domain
  }
}

resource "cloudflare_worker" "webshop_frontend" {
  account_id = local.cloudflare_account_id
  name       = local.webshop_worker_name

  subdomain = {
    enabled          = false
    previews_enabled = false
  }
}

resource "cloudflare_workers_custom_domain" "webshop_frontend" {
  account_id  = local.cloudflare_account_id
  zone_id     = data.cloudflare_zone.root.zone_id
  environment = "production"
  hostname    = local.webshop_hostname
  service     = cloudflare_worker.webshop_frontend.name
}

Link to debug output

https://gist.github.com/ffrants/1ce45543d4707ff2f8b422e3934ff032

Panic output

N/A – no panic, only HTTP 500 error from Cloudflare API.

Expected output

The cloudflare_workers_custom_domain.webshop_frontend resource is created successfully and the Worker custom domain is configured via the /accounts/<ACCOUNT_ID>/workers/domains API without errors.

Actual output

The Worker service itself is created successfully by cloudflare_worker.webshop_frontend, but cloudflare_workers_custom_domain.webshop_frontend fails with a 500 error from the Cloudflare API.

Terraform apply output:

cloudflare_workers_custom_domain.webshop_frontend: Creating...
Error: failed to make http request

with cloudflare_workers_custom_domain.webshop_frontend,
on webshop_frontend_worker.tf line 20, in resource "cloudflare_workers_custom_domain" "webshop_frontend":
20: resource "cloudflare_workers_custom_domain" "webshop_frontend" {

PUT "https://api.cloudflare.com/client/v4/accounts/<ACCOUNT_ID>/workers/domains": 500 Internal Server Error
{
"result": null,
"success": false,
"errors": [
{
"code": 10013,
"message": "An unknown error has occurred. If this error persists, please file a report in workers-sdk (https://github.com/cloudflare/workers-sdk/issues) or reach out to your account team."
}
],
"messages": []
}

Steps to reproduce

1. Configure the Cloudflare provider with an API token that has:
   • Zone: Zone:Read, DNS:Edit
   • Account: Workers Scripts:Edit, Workers Builds Configuration:Edit
2. Use the minimal Terraform configuration from the "Terraform configuration files" section with:
   • env_id = "dev"
   • pixion_id_dev_domain = "example.com"
   • cloudflare_account_id = "<ACCOUNT_ID>"
3. Run:
   terraform apply -var-file=env/dev.auto.tfvars
4. Observe that:
   • cloudflare_worker.webshop_frontend is created successfully.
   • cloudflare_workers_custom_domain.webshop_frontend fails with a 500 error (code 10013) on PUT /accounts/<ACCOUNT_ID>/workers/domains.

Additional factoids

I originally reported this to the Workers SDK team here:
cloudflare/workers-sdk#11412

They confirmed this should be handled by the Terraform provider team and asked me to open an issue here.

This behaviour is 100% reproducible for this account/zone/hostname combination. Retrying the same configuration always returns the same 500 / 10013 error.

References

Related Workers SDK issue:
cloudflare/workers-sdk#11412

[KaydeeDee]

Thanks for submitting an issue! I've created a ticker for the Workers team to investigate.