Health check endpoints in Express - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a health check endpoint in an Express app?

A health check endpoint is a simple URL route that returns a quick response to show the app is running and healthy. It helps monitoring tools know the app is alive.

beginner

Why should health check endpoints return fast responses?

Fast responses ensure monitoring tools get quick feedback about the app's status without slowing down the app or causing timeouts.

beginner

Which HTTP status code is commonly used for a successful health check response?

HTTP status code 200 means OK and is commonly used to show the app is healthy.

beginner

How can you create a basic health check endpoint in Express?

Use app.get('/health', (req, res) => res.status(200).send('OK')) to create a simple route that returns 'OK' with status 200.

intermediate

What extra checks can a health check endpoint perform besides just responding?

It can check database connections, external services, or disk space to confirm the app's full health, not just if it is running.

What is the main purpose of a health check endpoint in Express?

A To confirm the app is running and healthy

B To serve the main website content

C To handle user login

D To store user data

Health check endpoints are designed to quickly confirm the app is alive and working.

Which HTTP method is typically used for health check endpoints?

A PUT

B POST

C GET

D DELETE

GET is used because health checks just request status without changing data.

What status code should a healthy Express app return on its health check endpoint?

A 200

B 500

C 404

D 302

200 means OK and signals the app is healthy.

Which of these is NOT a good practice for health check endpoints?

A Respond quickly

B Perform heavy database queries

C Return simple status messages

D Use a dedicated route like '/health'

Heavy queries slow down health checks and can cause false failures.

How can health check endpoints help in real-life app monitoring?

A By sending marketing emails

B By storing user passwords

C By updating the app automatically

D By showing if the app is down or slow

Health checks let monitoring systems detect downtime or performance issues.

Explain how to create a simple health check endpoint in Express and why it is useful.

Think about a quick way to tell if your app is alive.

Describe what additional checks a health check endpoint might perform beyond just responding with 'OK'.

Consider what else affects app health besides just running.