cenjie/sentry-cloudflare-sdk

All Skills > SDK Setup > Cloudflare SDK

Sentry Cloudflare SDK

Opinionated wizard that scans your Cloudflare project and guides you through complete Sentry setup for Workers, Pages, Durable Objects, Queues, Workflows, and Hono.

Invoke This Skill When

• User asks to "add Sentry to Cloudflare Workers" or "set up Sentry" in a Cloudflare project
• User wants to install or configure @sentry/cloudflare
• User wants error monitoring, tracing, logging, crons, or AI monitoring for Cloudflare Workers or Pages
• User asks about withSentry, sentryPagesPlugin, instrumentDurableObjectWithSentry, or instrumentD1WithSentry
• User wants to monitor Durable Objects, Queues, Workflows, Scheduled handlers, or Email handlers on Cloudflare

Note: SDK versions and APIs below reflect current Sentry docs at time of writing (@sentry/cloudflare v10.55.0). Always verify against docs.sentry.io/platforms/javascript/guides/cloudflare/ before implementing.

---

Phase 1: Detect

Run these commands to understand the project before making any recommendations:

# Detect Cloudflare project
ls wrangler.toml wrangler.jsonc wrangler.json 2>/dev/null

# Detect existing Sentry
cat package.json 2>/dev/null | grep -E '"@sentry/'

# Detect project type (Workers vs Pages)
ls functions/ functions/_middleware.js functions/_middleware.ts 2>/dev/null && echo "Pages detected"
cat wrangler.toml 2>/dev/null | grep -E 'main|pages_build_output_dir'

# Detect framework
cat package.json 2>/dev/null | grep -E '"hono"|"remix"|"astro"|"svelte"'

# Detect Durable Objects
cat wrangler.toml 2>/dev/null | grep -i 'durable_objects'

# Detect D1 databases
cat wrangler.toml 2>/dev/null | grep -i 'd1_databases'

# Detect Queues
cat wrangler.toml 2>/dev/null | grep -i 'queues'

# Detect Workflows
cat wrangler.toml 2>/dev/null | grep -i 'workflows'

# Detect Scheduled handlers (cron triggers)
cat wrangler.toml 2>/dev/null | grep -i 'crons\|triggers'

# Detect compatibility flags
cat wrangler.toml 2>/dev/null | grep -i 'compatibility_flags'
cat wrangler.jsonc 2>/dev/null | grep -i 'compatibility_flags'

# Detect AI/LLM libraries
cat package.json 2>/dev/null | grep -E '"openai"|"@anthropic-ai"|"ai"|"@google/generative-ai"|"@langchain"'

# Detect logging libraries
cat package.json 2>/dev/null | grep -E '"pino"|"winston"'

# Check for companion frontend
ls frontend/ web/ client/ 2>/dev/null
cat package.json 2>/dev/null | grep -E '"react"|"vue"|"svelte"|"next"'

What to determine:

| Question | Impact | |----------|--------| | Workers or Pages? | Determines wrapper: withSentry vs sentryPagesPlugin | | Hono framework? | Recommend standalone @sentry/hono package (v10.55.0+) for cleaner integration | | @sentry/cloudflare already installed? | Skip install, go to feature config | | Durable Objects configured? | Recommend instrumentDurableObjectWithSentry | | D1 databases bound? | Recommend instrumentD1WithSentry | | Queues configured? | withSentry auto-instruments queue handlers | | Workflows configured? | Recommend instrumentWorkflowWithSentry | | Cron triggers configured? | withSentry auto-instruments scheduled handlers; recommend Crons monitoring | | nodejs_als or nodejs_compat flag set? | Required — SDK needs AsyncLocalStorage | | AI/LLM libraries? | Recommend AI Monitoring integrations | | Companion frontend? | Trigger Phase 4 cross-link |

---

Phase 2: Recommend

Present a concrete recommendation based on what you found. Don't ask open-ended questions — lead with a proposal:

Recommended (core coverage):

• ✅ Error Monitoring — always; captures unhandled exceptions in fetch, scheduled, queue, email, and Durable Object handlers
• ✅ Tracing — automatic HTTP request spans, outbound fetch tracing, D1 query spans

Optional (enhanced observability):

• ⚡ Logging — structured logs via Sentry.logger.*; recommend when log search is needed
• ⚡ Crons — detect missed/failed scheduled jobs; recommend when cron triggers are configured
• ⚡ D1 Instrumentation — automatic query spans and breadcrumbs; recommend when D1 is bound
• ⚡ Durable Objects — automatic error capture and spans for DO methods; recommend when DOs are configured
• ⚡ Workflows — automatic span creation for workflow steps; recommend when Workflows are configured
• ⚡ AI Monitoring — Vercel AI SDK, OpenAI, Anthropic, LangChain; recommend when AI libraries detected

Recommendation logic:

| Feature | Recommend when... | |---------|------------------| | Error Monitoring | Always — non-negotiable baseline | | Tracing | Always — HTTP request tracing and outbound fetch are high-value | | Logging | App needs structured log search or log-to-trace correlation | | Crons | Cron triggers configured in wrangler.toml | | D1 Instrumentation | D1 database bindings present | | Durable Objects | Durable Object bindings configured | | Workflows | Workflow bindings configured | | AI Monitoring | App uses Vercel AI SDK, OpenAI, Anthropic, or LangChain | | Metrics | App needs custom counters, gauges, or distributions |

Propose: "I recommend setting up Error Monitoring + Tracing. Want me to also add D1 instrumentation and Crons monitoring?"

---

Phase 3: Guide

Option 1: Source Maps Wizard

You need to run this yourself — the wizard opens a browser for login and requires interactive input that the agent can't handle. Copy-paste into your terminal:

npx @sentry/wizard@latest -i sourcemaps

This sets up source map uploading so your production stack traces show readable code. It does not set up the SDK initialization — you still need to follow Option 2 below for the actual SDK setup.

Once it finishes, continue with Option 2 for SDK setup.

Note: Unlike framework SDKs (Next.js, SvelteKit), there is no Cloudflare-specific wizard integration. The sourcemaps wizard only handles source map upload configuration.

---

Option 2: Manual Setup

Prerequisites: Compatibility Flags

The SDK requires AsyncLocalStorage. Add one of these flags to your Wrangler config:

wrangler.toml:

compatibility_flags = ["nodejs_als"]
# or: compatibility_flags = ["nodejs_compat"]

wrangler.jsonc:

{
  "compatibility_flags": ["nodejs_als"]
}

nodejs_als is lighter — it only enables AsyncLocalStorage. Use nodejs_compat if your code also needs other Node.js APIs.

Install

npm install @sentry/cloudflare

Workers Setup

Wrap your handler with withSentry. This automatically instruments fetch, scheduled, queue, email, and tail handlers:

import * as Sentry from "@sentry/cloudflare";

export default Sentry.withSentry(
  (env: Env) => ({
    dsn: env.SENTRY_DSN,
    tracesSampleRate: 1.0,
    enableLogs: true,
    dataCollection: {
      // To disable sending user data and HTTP bodies, uncomment the lines below. For more info visit:
      // https://docs.sentry.io/platforms/javascript/guides/cloudflare/configuration/options/#dataCollection
      // userInfo: false,
      // httpBodies: [],
    },
  }),
  {
    async fetch(request, env, ctx) {
      return new Response("Hello World!");
    },
  } satisfies ExportedHandler<Env>,
);

Key points:

• The first argument is a callback that receives env — use this to read secrets like SENTRY_DSN
• The SDK reads DSN, environment, release, debug, tunnel, and traces sample rate from env automatically (see Environment Variables)
• withSentry wraps all exported handlers — you do not need separate wrappers for scheduled, queue, etc.

Pages Setup

Use sentryPagesPlugin as middleware:

// functions/_middleware.ts
import * as Sentry from "@sentry/cloudflare";

export const onRequest = Sentry.sentryPagesPlugin((context) => ({
  dsn: context.env.SENTRY_DSN,
  tracesSampleRate: 1.0,
  enableLogs: true,
  dataCollection: {
    // To disable sending user data and HTTP bodies, uncomment the lines below. For more info visit:
    // https://docs.sentry.io/platforms/javascript/guides/cloudflare/configuration/options/#dataCollection
    // userInfo: false,
    // httpBodies: [],
  },
}));

Chaining multiple middlewares:

import * as Sentry from "@sentry/cloudflare";

export const onRequest = [
  // Sentry must be first
  Sentry.sentryPagesPlugin((context) => ({
    dsn: context.env.SENTRY_DSN,
    tracesSampleRate: 1.0,
  })),
  // Add more middlewares here
];

Using wrapRequestHandler directly (for frameworks like SvelteKit on Cloudflare Pages):

import * as Sentry from "@sentry/cloudflare";

export const handle = ({ event, resolve }) => {
  return Sentry.wrapRequestHandler(
    {
      options: {
        dsn: event.platform.env.SENTRY_DSN,
        tracesSampleRate: 1.0,
      },
      request: event.request,
      context: event.platform.ctx,
    },
    () => resolve(event),
  );
};

Hono on Cloudflare Workers

Recommended (v10.55.0+): Use the standalone @sentry/hono package for Hono apps:

npm install @sentry/hono @sentry/cloudflare

The @sentry/cloudflare package is a peer dependency and must stay in sync with @sentry/hono.

import { Hono } from "hono";
import { sentry } from "@sentry/hono/cloudflare";

type Bindings = { SENTRY_DSN: string };

const app = new Hono<{ Bindings: Bindings }>();

// Initialize Sentry middleware as early as possible
app.use(
  sentry(app, (env) => ({
    dsn: env.SENTRY_DSN,
    tracesSampleRate: 1.0,
  })),
);

app.get("/", (ctx) => ctx.json({ message: "Hello" }));

app.get("/error", () => {
  throw new Error("Test error");
});

export default app;

The sentry() middleware automatically captures errors and creates transaction spans with route patterns.

Legacy approach (deprecated): Using @sentry/cloudflare with withSentry still works, but honoIntegration is deprecated:

import { Hono } from "hono";
import * as Sentry from "@sentry/cloudflare";

const app = new Hono();

app.get("/", (ctx) => ctx.json({ message: "Hello" }));

export default Sentry.withSentry(
  (env: Env) => ({
    dsn: env.SENTRY_DSN,
    tracesSampleRate: 1.0,
  }),
  app,
);

Set Up the SENTRY_DSN Secret

Store your DSN as a Cloudflare secret — do not hardcode it:

# Local development: add to .dev.vars
echo 'SENTRY_DSN="https://[email protected]/0"' >> .dev.vars

# Production: set as a secret
npx wrangler secret put SENTRY_DSN

Add the binding to your Env type:

interface Env {
  SENTRY_DSN: string;
  // ... other bindings
}

Source Maps Setup

Source maps make production stack traces readable. Without them, you see minified/bundled code.

Step 1: Generate a Sentry auth token

Go to sentry.io/settings/auth-tokens/ and create a token with project:releases and org:read scopes.

Step 2: Install the Sentry Vite plugin (most Cloudflare projects use Vite via Wrangler):

npm install @sentry/vite-plugin --save-dev

Step 3: Configure vite.config.ts (if your project has one):

import { defineConfig } from "vite";
import { sentryVitePlugin } from "@sentry/vite-plugin";

export default defineConfig({
  build: {
    sourcemap: true,
  },
  plugins: [
    sentryVitePlugin({
      org: "___ORG_SLUG___",
      project: "___PROJECT_SLUG___",
      authToken: process.env.SENTRY_AUTH_TOKEN,
    }),
  ],
});

Step 4: Set environment variables in CI

SENTRY_AUTH_TOKEN=sntrys_eyJ...
SENTRY_ORG=my-org
SENTRY_PROJECT=my-project

Step 5: Add to .gitignore

.dev.vars
.env.sentry-build-plugin

---

Automatic Release Detection

The SDK can automatically detect the release version via Cloudflare's version metadata binding:

wrangler.toml:

[version_metadata]
binding = "CF_VERSION_METADATA"

Release priority (highest to lowest):

1. release option passed to Sentry.init()
2. SENTRY_RELEASE environment variable
3. CF_VERSION_METADATA.id binding

---

For Each Agreed Feature

Load the corresponding reference file and follow its steps:

| Feature | Reference file | Load when... | |---------|---------------|-------------| | Error Monitoring | references/error-monitoring.md | Always (baseline) — unhandled exceptions, manual capture, scopes, enrichment | | Tracing | references/tracing.md | HTTP request tracing, outbound fetch spans, D1 query spans, distributed tracing | | Logging | references/logging.md | Structured logs via Sentry.logger.*, log-to-trace correlation | | Crons | references/crons.md | Scheduled handler monitoring, withMonitor, check-in API | | Durable Objects | references/durable-objects.md | Instrument Durable Object classes for error capture and spans |

For each feature: read the reference file, follow its steps exactly, and verify before moving on.

---

Verification

After setup, verify Sentry is working:

// Add temporarily to your fetch handler, then remove
export default Sentry.withSentry(
  (env: Env) => ({
    dsn: env.SENTRY_DSN,
    tracesSampleRate: 1.0,
  }),
  {
    async fetch(request, env, ctx) {
      throw new Error("Sentry test error — delete me");
    },
  } satisfies ExportedHandler<Env>,
);

Deploy and trigger the route, then check your Sentry Issues dashboard — the error should appear within ~30 seconds.

Verification checklist:

| Check | How | |-------|-----| | Errors captured | Throw in a fetch handler, verify in Sentry | | Tracing working | Check Performance tab for HTTP spans | | Source maps working | Check stack trace shows readable file/line names | | D1 spans (if configured) | Run a D1 query, check for db.query spans | | Scheduled monitoring (if configured) | Trigger a cron, check Crons dashboard |

---

Config Reference

Sentry.init() Options

| Option | Type | Default | Notes | |--------|------|---------|-------| | dsn | string | — | Required. Read from env.SENTRY_DSN automatically if not set | | tracesSampleRate | number | — | 0–1; 1.0 in dev, lower in prod recommended | | tracesSampler | function | — | Dynamic sampling function; mutually exclusive with tracesSampleRate | | dataCollection | object | {} | Controls what data the SDK captures (userInfo, httpBodies, etc.). See Data Collection Reference | | sendDefaultPii | boolean | false | Legacy. Prefer dataCollection for control over captured data | | enableLogs | boolean | false | Enable Sentry Logs product | | environment | string | auto | Read from env.SENTRY_ENVIRONMENT if not set | | release | string | auto | Detected from CF_VERSION_METADATA.id or SENTRY_RELEASE | | debug | boolean | false | Read from env.SENTRY_DEBUG if not set. Log SDK activity to console | | tunnel | string | — | Read from env.SENTRY_TUNNEL if not set | | beforeSend | function | — | Filter/modify error events before sending | | beforeSendTransaction | function | — | Filter/modify transaction events before sending | | beforeSendLog | function | — | Filter/modify log entries before sending | | tracePropagationTargets | (string\|RegExp)[] | all URLs | Control which outbound requests get trace headers | | skipOpenTelemetrySetup | boolean | false | Opt-out of OpenTelemetry compatibility tracer | | instrumentPrototypeMethods | boolean \| string[] | false | Durable Object: instrument prototype methods for RPC spans |

Data Collection Reference

dataCollection: {
  // To disable sending user data and HTTP bodies, uncomment the lines below. For more info visit:
  // https://docs.sentry.io/platforms/javascript/configuration/options/#dataCollection
  // userInfo: false,
  // httpBodies: [],
},

Environment Variables (Read from env)

The SDK reads these from the Cloudflare env object automatically:

| Variable | Purpose | |----------|---------| | SENTRY_DSN | DSN for Sentry init | | SENTRY_RELEASE | Release version string | | SENTRY_ENVIRONMENT | Environment name (production, staging) | | SENTRY_TRACES_SAMPLE_RATE | Traces sample rate (parsed as float) | | SENTRY_DEBUG | Enable debug mode ("true" / "1") | | SENTRY_TUNNEL | Tunnel URL for event proxying | | CF_VERSION_METADATA | Cloudflare version metadata binding (auto-detected release) |

Default Integrations

These are registered automatically by getDefaultIntegrations():

| Integration | Purpose | |-------------|---------| | dedupeIntegration | Prevent duplicate events (disabled for Workflows) | | inboundFiltersIntegration | Filter events by type, message, URL | | functionToStringIntegration | Preserve original function names | | linkedErrorsIntegration | Follow cause chains in errors | | fetchIntegration | Trace outbound fetch() calls, create breadcrumbs | | honoIntegration | Deprecated in v10.55.0 — use @sentry/hono package instead. Auto-capture Hono onError exceptions | | requestDataIntegration | Attach request data to events | | consoleIntegration | Capture console.* calls as breadcrumbs |

---

Phase 4: Cross-Link

After completing Cloudflare setup, check for companion services:

# Check for companion frontend
ls frontend/ web/ client/ ui/ 2>/dev/null
cat package.json 2>/dev/null | grep -E '"react"|"vue"|"svelte"|"next"|"astro"'

# Check for companion backend in adjacent directories
ls ../backend ../server ../api 2>/dev/null
cat ../go.mod ../requirements.txt ../Gemfile 2>/dev/null | head -3

If a frontend is found, suggest the matching SDK skill:

| Frontend detected | Suggest skill | |------------------|--------------| | React | sentry-react-sdk | | Next.js | sentry-nextjs-sdk | | Svelte/SvelteKit | sentry-svelte-sdk | | Vue/Nuxt | See docs.sentry.io/platforms/javascript/guides/vue/ |

If a backend is found in a different directory:

| Backend detected | Suggest skill | |-----------------|--------------| | Go (go.mod) | sentry-go-sdk | | Python (requirements.txt, pyproject.toml) | sentry-python-sdk | | Ruby (Gemfile) | sentry-ruby-sdk | | Node.js (Express, Fastify) | sentry-node-sdk |

Connecting frontend and backend with linked Sentry projects enables distributed tracing — stack traces that span your browser, Cloudflare Worker, and backend API in a single trace view.

---

Troubleshooting

| Issue | Cause | Solution | |-------|-------|----------| | Events not appearing | DSN not set or debug: false hiding errors | Set debug: true temporarily in init options; verify SENTRY_DSN secret is set with wrangler secret list | | AsyncLocalStorage is not defined | Missing compatibility flag | Add nodejs_als or nodejs_compat to compatibility_flags in wrangler.toml | | Stack traces show minified code | Source maps not uploaded | Configure @sentry/vite-plugin or run npx @sentry/wizard -i sourcemaps; verify SENTRY_AUTH_TOKEN in CI | | Events lost on short-lived requests | SDK not flushing before worker terminates | Ensure withSentry or sentryPagesPlugin wraps your handler — they use ctx.waitUntil() to flush | | Hono errors not captured | Hono app not instrumented | Use @sentry/hono/cloudflare — import sentry middleware and call app.use(sentry(app, options)) | | Durable Object errors missing | DO class not instrumented | Wrap class with Sentry.instrumentDurableObjectWithSentry() — see references/durable-objects.md | | D1 queries not creating spans | D1 binding not instrumented | Wrap binding with Sentry.instrumentD1WithSentry(env.DB) before use | | Scheduled handler not monitored | withSentry not wrapping the handler | Ensure export default Sentry.withSentry(...) wraps your entire exported handler object | | Release not auto-detected | CF_VERSION_METADATA binding not configured | Add [version_metadata] with binding = "CF_VERSION_METADATA" to wrangler.toml | | Duplicate events in Workflows | Dedupe integration filtering step failures | SDK automatically disables dedupe for Workflows; verify you use instrumentWorkflowWithSentry |