diff --git a/dev-packages/e2e-tests/test-applications/node-fastify-app/package.json b/dev-packages/e2e-tests/test-applications/node-fastify-app/package.json
index 9e8779cf9bdd..56c8818933af 100644
--- a/dev-packages/e2e-tests/test-applications/node-fastify-app/package.json
+++ b/dev-packages/e2e-tests/test-applications/node-fastify-app/package.json
@@ -3,10 +3,11 @@
   "version": "1.0.0",
   "private": true,
   "scripts": {
-    "start": "node src/app.js",
+    "start": "ts-node src/app.ts",
     "test": "playwright test",
     "clean": "npx rimraf node_modules pnpm-lock.yaml",
-    "test:build": "pnpm install",
+    "typecheck": "tsc",
+    "test:build": "pnpm install && pnpm run typecheck",
     "test:assert": "pnpm test"
   },
   "dependencies": {
diff --git a/dev-packages/e2e-tests/test-applications/node-fastify-app/src/app.js b/dev-packages/e2e-tests/test-applications/node-fastify-app/src/app.ts
similarity index 71%
rename from dev-packages/e2e-tests/test-applications/node-fastify-app/src/app.js
rename to dev-packages/e2e-tests/test-applications/node-fastify-app/src/app.ts
index dbb239a4e340..187d259b1f5b 100644
--- a/dev-packages/e2e-tests/test-applications/node-fastify-app/src/app.js
+++ b/dev-packages/e2e-tests/test-applications/node-fastify-app/src/app.ts
@@ -1,8 +1,21 @@
-require('./tracing');
+import type * as S from '@sentry/node';
+const Sentry = require('@sentry/node') as typeof S;
+
+Sentry.init({
+  environment: 'qa', // dynamic sampling bias to keep transactions
+  dsn: process.env.E2E_TEST_DSN,
+  integrations: [],
+  tracesSampleRate: 1,
+  tunnel: 'http://localhost:3031/', // proxy server
+  tracePropagationTargets: ['http://localhost:3030', '/external-allowed'],
+});
+
+import type * as H from 'http';
+import type * as F from 'fastify';
 
-const Sentry = require('@sentry/node');
-const { fastify } = require('fastify');
-const http = require('http');
+// Make sure fastify is imported after Sentry is initialized
+const { fastify } = require('fastify') as typeof F;
+const http = require('http') as typeof H;
 
 const app = fastify();
 const port = 3030;
@@ -10,28 +23,28 @@ const port2 = 3040;
 
 Sentry.setupFastifyErrorHandler(app);
 
-app.get('/test-success', function (req, res) {
+app.get('/test-success', function (_req, res) {
   res.send({ version: 'v1' });
 });
 
-app.get('/test-param/:param', function (req, res) {
+app.get<{ Params: { param: string } }>('/test-param/:param', function (req, res) {
   res.send({ paramWas: req.params.param });
 });
 
-app.get('/test-inbound-headers/:id', function (req, res) {
+app.get<{ Params: { id: string } }>('/test-inbound-headers/:id', function (req, res) {
   const headers = req.headers;
 
   res.send({ headers, id: req.params.id });
 });
 
-app.get('/test-outgoing-http/:id', async function (req, res) {
+app.get<{ Params: { id: string } }>('/test-outgoing-http/:id', async function (req, res) {
   const id = req.params.id;
   const data = await makeHttpRequest(`http://localhost:3030/test-inbound-headers/${id}`);
 
   res.send(data);
 });
 
-app.get('/test-outgoing-fetch/:id', async function (req, res) {
+app.get<{ Params: { id: string } }>('/test-outgoing-fetch/:id', async function (req, res) {
   const id = req.params.id;
   const response = await fetch(`http://localhost:3030/test-inbound-headers/${id}`);
   const data = await response.json();
@@ -55,7 +68,7 @@ app.get('/test-error', async function (req, res) {
   res.send({ exceptionId });
 });
 
-app.get('/test-exception/:id', async function (req, res) {
+app.get<{ Params: { id: string } }>('/test-exception/:id', async function (req, res) {
   throw new Error(`This is an exception with id ${req.params.id}`);
 });
 
@@ -101,9 +114,9 @@ app2.get('/external-disallowed', function (req, res) {
 
 app2.listen({ port: port2 });
 
-function makeHttpRequest(url) {
+function makeHttpRequest(url: string) {
   return new Promise(resolve => {
-    const data = [];
+    const data: any[] = [];
 
     http
       .request(url, httpRes => {
diff --git a/dev-packages/e2e-tests/test-applications/node-fastify-app/src/tracing.js b/dev-packages/e2e-tests/test-applications/node-fastify-app/src/tracing.js
deleted file mode 100644
index 136b401cbd73..000000000000
--- a/dev-packages/e2e-tests/test-applications/node-fastify-app/src/tracing.js
+++ /dev/null
@@ -1,10 +0,0 @@
-const Sentry = require('@sentry/node');
-
-Sentry.init({
-  environment: 'qa', // dynamic sampling bias to keep transactions
-  dsn: process.env.E2E_TEST_DSN,
-  integrations: [],
-  tracesSampleRate: 1,
-  tunnel: 'http://localhost:3031/', // proxy server
-  tracePropagationTargets: ['http://localhost:3030', '/external-allowed'],
-});
diff --git a/packages/node/src/integrations/tracing/fastify.ts b/packages/node/src/integrations/tracing/fastify.ts
index 87a820bd238e..aa2b2f275525 100644
--- a/packages/node/src/integrations/tracing/fastify.ts
+++ b/packages/node/src/integrations/tracing/fastify.ts
@@ -31,8 +31,10 @@ export const fastifyIntegration = defineIntegration(_fastifyIntegration);
 
 // We inline the types we care about here
 interface Fastify {
-  register: (plugin: unknown) => void;
-  addHook: (hook: string, handler: (request: unknown, reply: unknown, error: Error) => void) => void;
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  register: (plugin: any) => void;
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  addHook: (hook: string, handler: (request: any, reply: any, error: Error) => void) => void;
 }
 
 /**
@@ -53,7 +55,7 @@ interface FastifyRequestRouteInfo {
  */
 export function setupFastifyErrorHandler(fastify: Fastify): void {
   const plugin = Object.assign(
-    function (fastify: Fastify, options: unknown, done: () => void): void {
+    function (fastify: Fastify, _options: unknown, done: () => void): void {
       fastify.addHook('onError', async (_request, _reply, error) => {
         captureException(error);
       });