Chapter 07 — APIs at work6 min read

Chapter quiz

Test yourself

You've seen how real integrations work end to end, learned to evaluate APIs, tested your own, and built the vocabulary to talk to your engineering team. Let's see what stuck.


Integration scenarios

Your e-commerce app needs to send order confirmation emails. You decide to use an external email API. What's the correct sequence of steps?

Twilio uses Basic Authentication. What does that mean in practice?

You send an SMS via Twilio's API and get back status: queued in the response. How do you know when the SMS is actually delivered?


Evaluating APIs

You're comparing two SMS providers. Provider A charges $0.005/message with a rate limit of 30/second. Provider B charges $0.008/message with a rate limit of 200/second. Your app sends 50,000 marketing messages during flash sales. Which factor matters most here?

What is developer experience (DX)?

An API provider advertises 99.9% uptime. How much downtime is that per year?


Testing your own API

Why should a PM test their own product's public API?

You remove the API key from a request to your product's API and get back just '401 Unauthorized' with no other details. Is this a problem?


Communicating with your team

Your engineer says: "The API returns paginated results." What does this mean for your feature that displays a user's full order history?

Your engineer says: "We're getting 429 errors from the API." What's happening?

Your team is integrating a calendar API and mentions it uses OAuth. What's the most useful question you can ask?