<!--
title: Secure Fastify Code Implementation
domain: app-frameworks
topic: Fastify
language: TypeScript
source: fastify/fastify
updated: 
url: https://awesomereviewers.com/reviewers/fastify-secure-fastify-code-implementation/
-->

This review focuses on secure implementation patterns when using the Fastify web framework in TypeScript:

1. **Prevent Prototype Pollution Attacks**: Avoid direct property access on untrusted objects. Instead, use `Object.prototype` methods to safely access object properties:

```typescript
// Vulnerable approach
fastify.get('/route', (req, reply) => {
  console.log(req.params.hasOwnProperty('name')); // Potential prototype pollution vulnerability
  return { hello: req.params.name };
});

// Secure approach
fastify.get('/route', (req, reply) => {
  console.log(Object.prototype.hasOwnProperty.call(req.params, 'name')); // Safe property access
  return { hello: req.params.name };
}); 
```

2. **Protect Against Denial-of-Service Attacks**: Configure appropriate request timeouts, especially when deploying Fastify without a reverse proxy:

```typescript
const fastify = Fastify({
  requestTimeout: 120000 // Set a non-zero timeout (e.g., 120 seconds)
});
```

These security measures help mitigate common web application vulnerabilities when using the Fastify framework.