Add Sentry error monitoring (edge-compatible)

[RisingOrange]

Adds Sentry error monitoring so we get notified when users hit errors, with stack traces and context to debug them. Resolves #707, alternative to #714.

@sentry/sveltekit doesn't support non-Node.js edge runtimes, which includes Netlify edge functions (Deno). This PR uses the individual Sentry SDKs instead.

Approach

• Client: @sentry/svelte in src/hooks.client.ts
• Server: @sentry/deno (dynamically imported) in src/hooks.server.ts
• Source maps: @sentry/vite-plugin + postbuild script for edge function maps

Details

• DSN comes from PUBLIC_SENTRY_DSN env var (not hardcoded)
• Tracing disabled (tracesSampleRate: 0) — not useful for a content site
• Session replay disabled — avoids bundle bloat
• Server-side logs enabled (enableLogs: true in @sentry/deno)
• Release tagged with git SHA for source map symbolication
• @sentry/deno is dynamically imported to avoid conflicts with the Netlify Deno window stub fix, and skipped during Node.js prerender
• Both hooks use SvelteKit's init hook (since 2.10) to ensure Sentry is ready before the first request
• Server handleError uses event.platform.context.waitUntil to flush events without blocking the error response
• Postbuild script injects Debug IDs into edge function bundles before uploading source maps (the Vite plugin runs before adapter-netlify creates them)

Required env vars (Netlify)

• PUBLIC_SENTRY_DSN — Sentry DSN (already configured)
• SENTRY_AUTH_TOKEN — for source map uploads
• SENTRY_ORG — Sentry org slug
• SENTRY_PROJECT — Sentry project slug

Risk

@sentry/deno is in beta and may not work on Netlify's non-standard Deno edge runtime. If it fails at runtime, server-side error capture degrades silently (client-side still works). The dynamic import is wrapped in try/catch so a server SDK failure won't break the site.

[netlify]

👷 Deploy request for pauseai pending review.

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Name	Link
🔨 Latest commit	1488d90

[Wituareard]

Thanks, this doesn't capture logs yet right? That would be a neat addition but not super important. Could use the standardized waitUntil API for dispatching them (edit: and also for the errors maybe)

[RisingOrange]

Enabled enableLogs on the server (@sentry/deno supports it, @sentry/svelte doesn't).

waitUntil isn't available in SvelteKit's handleError hook since it doesn't expose the Netlify context object. I used await Sentry.flush(2000) instead.

[Wituareard]

Are you sure that it isn't available under event.platform?

[RisingOrange]

@Wituareard Oh, you're right. Updated to use that

[Wituareard]

npx didn't properly download the binary, so I had to add the CLI as a dependency

[Wituareard]

Source map upload works, but it produces 600 lines of log entries so that should probably be reduced

[Wituareard]

Nvm it was the Vite plugin that produced the logs

[Wituareard]

Nothing shows up in Sentry, can't take a closer look atm unfortunately

[RisingOrange]

Found the issue: hooks.client.ts was reading the DSN from import.meta.env.PUBLIC_SENTRY_DSN, which is always undefined in SvelteKit. SvelteKit doesn't expose PUBLIC_ prefixed env vars through import.meta.env, you have to use $env/dynamic/public instead. Fixed in 1488d90.

I tested with a custom Sentry project locally and confirmed client-side errors now show up.

I couldn't test server errors locally, because the dev server runs Node.js and @sentry/deno only loads on Netlify's Deno edge runtime.