4. Authentication & Security
Input Security, Rate Limits & Abuse
Defend public endpoints against malformed input, brute force, resource exhaustion and common attacks.
Lesson overview
Treat query parameters, JSON, files, headers, webhooks and third-party responses as untrusted. Validate shape, size and allowed values; use parameterized queries; rate-limit abuse-sensitive actions.
Learning path
Theory → Example → Code → Practice → Quiz → Challenge → Completion
Step 1
Theory
Treat query parameters, JSON, files, headers, webhooks and third-party responses as untrusted. Validate shape, size and allowed values; use parameterized queries; rate-limit abuse-sensitive actions.
Step 2
Example
A password-reset endpoint can rate-limit by IP and account, avoid account enumeration, and enqueue email delivery instead of performing expensive work inline.
Step 3
Code
typescript
const limit = await limiter.check({
key: reset:${ip},
limit: 5,
windowSeconds: 900,
});
Step 4
Practice
Review your current application and apply Input Security, Rate Limits & Abuse. Document the current behavior, one production risk, the change you would make, and how you would verify it.
Step 5
Quiz
1. What is the central production concern in "Input Security, Rate Limits & Abuse"?
Step 6
Challenge
Design a production-ready implementation for Input Security, Rate Limits & Abuse. Include failure handling, security considerations, observability, testing and a rollback or recovery path where applicable.
Complete every stage
Work through every step in order, then the lesson will be marked complete.
Each chapter and subtopic has its own public URL under /full-stack-to-production.