Lesson Complete!

Create an Expense

What you learned

  • How POST requests send data in the request body and how FastAPI maps that data to your function parameters
  • How to set up in-memory storage using a dictionary and a counter for unique identifiers
  • How to build a complete POST endpoint that validates input, assigns an identifier, stores the expense, and returns it
  • How to start the development server with automatic reloading
  • How to test your endpoint interactively using FastAPI's built-in Swagger UI at /docs

Next up

Your API can create expenses, but there is no way to retrieve them yet. In the next lesson, you will add a GET endpoint to list all expenses and filter them by category using query parameters.