Setup instructions for Cloudflare workers and Sveltekit lead to broken installation

[RaniSputnik]

Is there an existing issue for this?

• I have checked for existing issues https://github.com/getsentry/sentry-javascript/issues
• I have reviewed the documentation https://docs.sentry.io/
• I am using the latest SDK release https://github.com/getsentry/sentry-javascript/releases

How do you use Sentry?

Sentry Saas (sentry.io)

Which SDK are you using?

@sentry/cloudflare

SDK Version

9.35.0

Framework Version

Sveltekit 2.16.0

Link to Sentry event

No response

Reproduction Example/SDK Setup

https://github.com/RaniSputnik/sentry-issues/tree/enable-not-a-function

Steps to Reproduce

1. Follow the getting started guide for a new Sveltekit app, including using the Cloudflare adapter.
2. Run npx @sentry/wizard@latest -i sveltekit
3. Follow Cloudflare + Sveltekit specific setup instructions
4. Add a minimal wrangler.toml:

name = "some-project-name"
main = ".svelte-kit/cloudflare/_worker.js"
compatibility_date = "2025-01-01"

compatibility_flags = ["nodejs_compat"]
version_metadata = { binding = "CF_VERSION_METADATA" }

[assets]
binding = "assets"
directory = ".svelte-kit/cloudflare"

[observability]
enabled = true
head_sampling_rate = 1

Expected Result

My setup is functional. I can use the Sentry test error page to trigger client side + server side errors.

Actual Result

Symptom 1

I get intermittent 500's when trying to load the page with the following error in the logs:

TypeError: this.enable is not a function
    at new InstrumentationBase (_worker.js:17457:16)
    at new SentryHttpInstrumentation (_worker.js:28603:9)
    at _worker.js:28871:16
    at Object.assign.id (_worker.js:20577:31)
    at Object.setupOnce (_worker.js:28892:11)
    at setupIntegration (_worker.js:5979:17)
    at _worker.js:5960:7
    at Array.forEach (<anonymous>)
    at setupIntegrations (_worker.js:5958:16)
    at NodeClient._setupIntegrations (_worker.js:6576:30)

Symptom 2

I see 400's in the browser on every page load when posting to https://o447951.ingest.sentry.io:

{"detail":"bad sentry DSN public key","causes":["invalid project key"]}

Symptom 3

The Sentry example page raises and error client side and posts to an API route that also errors. It should produce two errors, one from the client and one from the server. Client errors are being reported, server errors are not:

[RaniSputnik]

I've just seen this page on Sveltekit adapter compatibility.

The SDK supports the following SvelteKit adapters:

• @sveltejs/adapter-auto - for Vercel with the Node runtime. Other deployment targets might work but we don't guarantee compatibility.
• @sveltejs/adapter-vercel - only for Node (Lambda) runtimes, not yet Vercel's edge runtime
• @sveltejs/adapter-node

If you use the SDK with other adapters, we cannot guarantee that everything works as expected. You might need to manually configure source maps upload. The SDK is currently not compatible with none-Node server runtimes, such as Vercel's Edge runtime or Cloudflare workers.

That seems to contradict the documentation which offers a setup guide for Cloudflare and SvelteKit without caveats. Now it's unclear to me what Sentry's position is.

Could you please clarify: Is the Cloudflare adapter for SvelteKit officially supported?

I think once that's answered, either the @sentry/sveltekit readme should be updated, or the documentation should have a caveat that this isn't an officially supported adapter.

Cheers! ✌️

[mydea]

Hello, one question: Are you getting this when running it locally, or when deployed to cloudflare? We do officially support this, but there may be some kinks to iron out.

I've seen similar things when running this locally with wrangler 3, in that case it got fixed by updating to wrangler 4. Also it was just an issue when running locally. Could this be the same problem

[RaniSputnik]

Hi @mydea

Are you getting this when running it locally, or when deployed to cloudflare?

I only see these issues when running on Cloudflare. When I run npm run dev locally, both issues are successfully reported to Sentry. I also don't see any errors (other than the one's thrown by the Sentry example) when running locally.

I can also confirm my example uses Wrangler 4.x:

$ npx wrangler --version
 ⛅️ wrangler 4.23.0

We do officially support this, but there may be some kinks to iron out.

Thanks for confirming, I can open a separate issue to improve that documentation.

[Lms24]

Hey, I'll take a look at this issue in a minute.

I think once that's answered, either the @sentry/sveltekit readme should be updated, or the documentation should have a caveat that this isn't an officially supported adapter.

Yes, the readme is outdated. Will update it.