diff --git a/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/deployed-worker.mjs b/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/deployed-worker.ts
similarity index 53%
rename from dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/deployed-worker.mjs
rename to dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/deployed-worker.ts
index 9dacbe052b8b..514927322439 100644
--- a/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/deployed-worker.mjs
+++ b/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/deployed-worker.ts
@@ -6,7 +6,7 @@ import { fileURLToPath } from 'node:url';
 
 const __dirname = dirname(fileURLToPath(import.meta.url));
 
-function wrangler(args, env = {}) {
+function wrangler(args: string[], env: Record<string, string> = {}): void {
   execFileSync('pnpm', ['exec', 'wrangler', ...args], {
     cwd: __dirname,
     env: { ...process.env, ...env },
@@ -18,10 +18,12 @@ function wrangler(args, env = {}) {
  * Workflow names are unique per Cloudflare account, so every worker gets its own. The Vite build writes the
  * config wrangler deploys from, and `.wrangler/deploy/config.json` points to it.
  */
-function nameWorkflowsAfterWorker(name) {
-  const redirect = JSON.parse(readFileSync(join(__dirname, '.wrangler/deploy/config.json'), 'utf8'));
+function nameWorkflowsAfterWorker(name: string): void {
+  const redirect: { configPath: string } = JSON.parse(
+    readFileSync(join(__dirname, '.wrangler/deploy/config.json'), 'utf8'),
+  );
   const configPath = join(__dirname, '.wrangler/deploy', redirect.configPath);
-  const config = JSON.parse(readFileSync(configPath, 'utf8'));
+  const config: { workflows?: { name: string }[] } = JSON.parse(readFileSync(configPath, 'utf8'));
 
   for (const workflow of config.workflows ?? []) {
     workflow.name = name;
@@ -30,7 +32,7 @@ function nameWorkflowsAfterWorker(name) {
 }
 
 /** Deploys the worker under `name` and returns its workers.dev URL. */
-export function deployWorker(name, dsn) {
+export function deployWorker(name: string, dsn: string): string {
   nameWorkflowsAfterWorker(name);
   const outputDir = mkdtempSync(join(tmpdir(), 'wrangler-output-'));
   const outputFile = join(outputDir, 'output.ndjson');
@@ -41,7 +43,7 @@ export function deployWorker(name, dsn) {
     const url = readFileSync(outputFile, 'utf8')
       .split('\n')
       .filter(Boolean)
-      .map(line => JSON.parse(line))
+      .map(line => JSON.parse(line) as { type?: string; targets?: string[] })
       .find(entry => entry.type === 'deploy')
       ?.targets?.find(target => target.endsWith('.workers.dev'));
 
@@ -55,7 +57,7 @@ export function deployWorker(name, dsn) {
   }
 }
 
-export function deleteWorker(name) {
+export function deleteWorker(name: string): void {
   wrangler(['delete', '--name', name, '--force']);
 }
 
@@ -63,12 +65,12 @@ export function deleteWorker(name) {
  * CI keeps its Workers: one per ref, overwritten by the next run of the same ref and deleted by the
  * cleanup workflow once a PR closes. Local runs delete theirs unless `E2E_KEEP_WORKER` is set.
  */
-export function keepsWorker() {
+export function keepsWorker(): boolean {
   return Boolean(process.env.GITHUB_ACTIONS || process.env.E2E_KEEP_WORKER);
 }
 
 /** A freshly created workers.dev route can take a moment to become reachable. */
-export async function waitForWorker(url) {
+export async function waitForWorker(url: string): Promise<void> {
   const deadline = Date.now() + 60_000;
 
   while (Date.now() < deadline) {
@@ -88,3 +90,39 @@ export async function waitForWorker(url) {
 
   throw new Error(`Worker at ${url} did not become reachable within 60s.`);
 }
+
+/**
+ * Sends a request until the Worker itself answers it, and returns the body of that answer.
+ *
+ * On the first deployment of a Worker name, Cloudflare has answered a request with a 500 while
+ * Workers Logs had no invocation for it. `status` is the status the Worker answers with. A Worker
+ * that threw answers with status 500 and Cloudflare error code 1101, which sets it apart from a 500
+ * that did not come from the Worker.
+ */
+export async function fetchFromWorker(url: string, status: number, init?: RequestInit): Promise<string> {
+  const deadline = Date.now() + 60_000;
+  let lastAnswer = 'no answer';
+
+  while (Date.now() < deadline) {
+    try {
+      const response = await fetch(url, init);
+      const body = await response.text();
+      // Cloudflare sends its error page as HTML to some clients (Node's fetch among them) and as
+      // `error code: <code>` plain text to others, so the code is read from either format.
+      const errorCode = /cf-error-code">(\d+)<|^error code: (\d+)/.exec(body)?.slice(1).find(Boolean);
+
+      if (response.status === status && (status !== 500 || errorCode === '1101')) {
+        return body;
+      }
+
+      lastAnswer = `${response.status}, cf-ray ${response.headers.get('cf-ray')}, error code ${errorCode ?? 'none'}, body: ${body.slice(0, 200)}`;
+    } catch (error) {
+      lastAnswer = String(error);
+    }
+
+    console.log(`The Worker did not answer ${url}: ${lastAnswer}`);
+    await new Promise(resolve => setTimeout(resolve, 2_000));
+  }
+
+  throw new Error(`The Worker did not answer ${url} with status ${status} within 60s. Last answer: ${lastAnswer}`);
+}
diff --git a/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/global-setup.mjs b/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/global-setup.ts
similarity index 94%
rename from dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/global-setup.mjs
rename to dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/global-setup.ts
index 08e9311cb7ca..b33f187e1d94 100644
--- a/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/global-setup.mjs
+++ b/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/global-setup.ts
@@ -1,6 +1,6 @@
 import { randomBytes } from 'node:crypto';
 import { existsSync } from 'node:fs';
-import { deleteWorker, deployWorker, keepsWorker, waitForWorker } from './deployed-worker.mjs';
+import { deleteWorker, deployWorker, keepsWorker, waitForWorker } from './deployed-worker';
 
 const WORKER_PREFIX = 'e2e-send-to-sentry';
 
@@ -9,7 +9,7 @@ const WORKER_PREFIX = 'e2e-send-to-sentry';
  * next run of the same ref overwrites. Pull request refs look like `123/merge` and merge queue refs
  * like `gh-readonly-queue/<base>/pr-123-<sha>`; both map to the PR's Worker.
  */
-export function getWorkerName() {
+export function getWorkerName(): string {
   if (!process.env.GITHUB_ACTIONS) {
     return `${WORKER_PREFIX}-local-${randomBytes(3).toString('hex')}`;
   }
@@ -24,7 +24,7 @@ export function getWorkerName() {
   return `${WORKER_PREFIX}-${slug}`.slice(0, 63).replace(/-+$/, '');
 }
 
-export default async function globalSetup() {
+export default async function globalSetup(): Promise<void> {
   if (!existsSync(new URL('.wrangler/deploy/config.json', import.meta.url))) {
     throw new Error('Run `pnpm build` first: wrangler would deploy the uninstrumented source.');
   }
diff --git a/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/global-teardown.mjs b/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/global-teardown.ts
similarity index 82%
rename from dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/global-teardown.mjs
rename to dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/global-teardown.ts
index 0fee903dc5c7..9f012cd51101 100644
--- a/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/global-teardown.mjs
+++ b/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/global-teardown.ts
@@ -1,6 +1,6 @@
-import { deleteWorker, keepsWorker } from './deployed-worker.mjs';
+import { deleteWorker, keepsWorker } from './deployed-worker';
 
-export default function globalTeardown() {
+export default function globalTeardown(): void {
   const workerName = process.env.E2E_TEST_WORKER_NAME;
 
   if (!workerName) {
diff --git a/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/package.json b/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/package.json
index 75bbb77d0b7c..3bebd9caebf1 100644
--- a/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/package.json
+++ b/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/package.json
@@ -5,7 +5,7 @@
   "type": "module",
   "scripts": {
     "build": "vite build",
-    "typecheck": "tsc --noEmit",
+    "typecheck": "tsc --noEmit && tsc --noEmit -p tsconfig.node.json",
     "test": "playwright test",
     "clean": "npx rimraf node_modules pnpm-lock.yaml dist .wrangler",
     "test:build": "pnpm install && pnpm build",
diff --git a/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/playwright.config.ts b/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/playwright.config.ts
index 0b79fb88052f..91e214f15493 100644
--- a/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/playwright.config.ts
+++ b/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/playwright.config.ts
@@ -3,8 +3,8 @@ import { defineConfig } from '@playwright/test';
 export default defineConfig({
   testDir: './tests',
   // The worker is deployed once for the whole run and deleted again afterwards.
-  globalSetup: './global-setup.mjs',
-  globalTeardown: './global-teardown.mjs',
+  globalSetup: './global-setup.ts',
+  globalTeardown: './global-teardown.ts',
   /* Spans take ~2min to become queryable via the trace endpoint. */
   timeout: 210_000,
   fullyParallel: true,
diff --git a/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/tests/send-to-sentry.test.ts b/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/tests/send-to-sentry.test.ts
index ab642bf55b1a..8578ecb7bee7 100644
--- a/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/tests/send-to-sentry.test.ts
+++ b/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/tests/send-to-sentry.test.ts
@@ -8,14 +8,15 @@ import {
   flattenTrace,
   traceTarget,
 } from '@sentry-internal/test-utils/cli';
+import { fetchFromWorker } from '../deployed-worker';
 
-// Set by global-setup.mjs once the worker for this run is deployed.
+// Set by global-setup.ts once the worker for this run is deployed.
 const workerUrl = process.env.E2E_TEST_WORKER_URL;
 
 test('Sends a captured exception to Sentry', async () => {
-  const response = await fetch(`${workerUrl}/test-error`);
-  expect(response.status).toBe(200);
-  const { eventId, traceId } = await response.json();
+  const { eventId, traceId }: { eventId: string; traceId: string } = JSON.parse(
+    await fetchFromWorker(`${workerUrl}/test-error`, 200),
+  );
 
   console.log(`Polling for error eventId ${eventId}: sentry trace view ${traceTarget(traceId)}`);
 
@@ -25,13 +26,12 @@ test('Sends a captured exception to Sentry', async () => {
 test('Sends an unhandled exception and its request span to Sentry', async () => {
   const traceId = randomBytes(16).toString('hex');
   const publicKey = new URL(process.env.E2E_TEST_DSN!).username;
-  const response = await fetch(`${workerUrl}/test-unhandled-error`, {
+  await fetchFromWorker(`${workerUrl}/test-unhandled-error`, 500, {
     headers: {
       'sentry-trace': `${traceId}-${randomBytes(8).toString('hex')}-1`,
       baggage: `sentry-trace_id=${traceId},sentry-public_key=${publicKey},sentry-sampled=true,sentry-sample_rate=1`,
     },
   });
-  expect(response.status).toBe(500);
 
   console.log(`Polling for unhandled error: sentry trace view ${traceTarget(traceId)}`);
 
@@ -40,9 +40,9 @@ test('Sends an unhandled exception and its request span to Sentry', async () =>
 });
 
 test('Sends a request span to Sentry', async () => {
-  const response = await fetch(`${workerUrl}/test-span`);
-  expect(response.status).toBe(200);
-  const { spanId, traceId } = await response.json();
+  const { spanId, traceId }: { spanId: string; traceId: string } = JSON.parse(
+    await fetchFromWorker(`${workerUrl}/test-span`, 200),
+  );
 
   console.log(`Polling for request spanId ${spanId}: sentry trace view ${traceTarget(traceId)}`);
 
@@ -52,9 +52,9 @@ test('Sends a request span to Sentry', async () => {
 });
 
 test('Sends the spans of Workflow steps before the Workflow goes to sleep', async () => {
-  const response = await fetch(`${workerUrl}/test-workflow-sleep`);
-  expect(response.status).toBe(200);
-  const { instanceId, traceId } = await response.json();
+  const { instanceId, traceId }: { instanceId: string; traceId: string } = JSON.parse(
+    await fetchFromWorker(`${workerUrl}/test-workflow-sleep`, 200),
+  );
 
   console.log(`Polling for the Workflow step spans: sentry trace view ${traceTarget(traceId)}`);
 
@@ -68,6 +68,8 @@ test('Sends the spans of Workflow steps before the Workflow goes to sleep', asyn
     )
     .toBe(3);
 
-  const { status } = await fetch(`${workerUrl}/test-workflow-status?id=${instanceId}`).then(res => res.json());
+  const { status }: { status: string } = JSON.parse(
+    await fetchFromWorker(`${workerUrl}/test-workflow-status?id=${instanceId}`, 200),
+  );
   expect(['running', 'waiting']).toContain(status);
 });
diff --git a/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/tsconfig.node.json b/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/tsconfig.node.json
new file mode 100644
index 000000000000..657ecc4ef24a
--- /dev/null
+++ b/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/tsconfig.node.json
@@ -0,0 +1,7 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "types": ["node"]
+  },
+  "include": ["tests/**/*", "deployed-worker.ts", "global-setup.ts", "global-teardown.ts", "playwright.config.ts"]
+}
diff --git a/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/wrangler.jsonc b/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/wrangler.jsonc
index 351a68bd023f..d6b15b1dbf5e 100644
--- a/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/wrangler.jsonc
+++ b/dev-packages/e2e-tests/test-applications/cloudflare-workers-send-to-sentry/wrangler.jsonc
@@ -1,6 +1,6 @@
 {
   "$schema": "node_modules/wrangler/config-schema.json",
-  // Placeholder only: every test run deploys under a unique name, see global-setup.mjs.
+  // Placeholder only: every test run deploys under a unique name, see global-setup.ts.
   "name": "cloudflare-workers-send-to-sentry",
   "main": "src/index.ts",
   "compatibility_date": "2026-05-20",