API Foundations
The mechanics of calling a market-data API — requests, identifiers, the two kinds of limit, error handling, and the habits that stop a beginner producing confidently wrong results.
Start here
What actually happens when you ask a server for a stock price?
Start the first lessonUnit 1 How an API Answers a Question
- What actually happens when you ask a server for a stock price?
- Which part of a request is doing the work?
- JSON or CSV, and why the default can bite you
- How do you answer your own API questions instead of guessing?
Practice Check · Unit 1 A short check · cannot be failed Start
Unit 2 Naming the Thing You Want
- Why isn't AAPL enough to name a stock?
- Why does a bare AAPL work when everything tells you to write AAPL.US?
- What happens to your history when a ticker gets renamed?
- Why is FOREX in the exchange list when it isn't an exchange?
Practice Check · Unit 2 A short check · cannot be failed Start
Unit 3 Limits, Cost and Failure
- Why does one script die at noon and another die in ten seconds?
- Why does the account endpoint call your daily quota a rate limit?
- Why did one request use 100 calls?
- What is the API telling you when it says no?
Practice Check · Unit 3 A short check · cannot be failed Start
Unit 4 Trusting What Comes Back
- Will the same historical query return the same rows tomorrow?
- What time is it in your data?
- Is that a zero, a null, or a day that never happened?
- API foundations — course checkpoint
Practice Check · Unit 4 A short check · cannot be failed Start
Last Course exam
One exam, the whole course Unlocks when you have read all 16 lessons
Passing it earns the course certificate. It also counts toward the Builder track (course 2 of 13): pass every course exam in a track to earn its track certificate.