Build your first API in 10 minutes | API tutorial | FastAPI tutorial | Build API from scratch

Summary

In this video, you'll learn how to build your own API in Python with just a few lines of code and host it on your machine. The video covers key concepts like API definitions, endpoints, API requests, and responses, alongside a demo using FastAPI. You'll also discover how to test APIs through a GUI and explore both GET and PUT methods for secure data handling. The tutorial emphasizes the importance of API keys for protection and ends with a homework challenge to host a machine learning model as an API.

Takeaways

• 😀 APIs allow one program to request functionality or data from another program without having to rewrite the logic itself.
• 😀 An API is essentially a service that provides predefined functionalities, saving time and effort by reusing existing code.
• 😀 An API's 'endpoint' is the URL where you send your requests to access the service's functionality.
• 😀 API requests and responses follow a fixed format; you cannot ask for random things outside the predefined logic.
• 😀 Using `FastAPI`, you can build and host APIs in just a few lines of Python code, which makes it an accessible choice for developers.
• 😀 The 'predict' endpoint is an example of how you can pass input parameters (like age and sex) to an API and get a response (e.g., whether a person survived based on some logic).
• 😀 Testing an API can be done through a browser or by using tools like Postman to send GET or POST requests.
• 😀 Passing sensitive data through the URL (e.g., in GET requests) is not safe; using a 'PUT' request with a payload is a better practice for security.
• 😀 An API key is used to protect the API from unwanted or abusive requests and to track usage (e.g., for billing or quota limits).
• 😀 To consume an API from another program, you can use Python's `requests` library, passing parameters in the request body rather than the URL for better security.

Q & A

What is an API and how is it used in programming?

An API (Application Programming Interface) is a set of rules and protocols that allows one program to communicate with another. It allows you to use functionality written by someone else in your own program, enabling you to access certain services, like fetching weather data or performing calculations, without needing to write the logic from scratch.

What is an API endpoint?

An API endpoint is a URL or a specific location where an API receives requests. It acts as the 'entry point' for sending queries and receiving responses. For example, the weather API provides a specific endpoint where you can query weather data by entering a city name.

What does the host mean by 'relearning the definition of an API'?

The host emphasizes simplifying the common understanding of APIs. Instead of thinking of them as overly complex concepts, they want viewers to understand that APIs are simply a way for programs to share functionality by asking for specific services (like adding numbers) through defined requests and receiving responses.

How is the 'weather API' example used to explain API usage?

The weather API is used as an example to show how an API endpoint works. The host demonstrates how a request can be made to the weather API by entering a city (like Bangalore), and how the API responds with data like the current weather, in a specific format like JSON.

What is FastAPI and why is it used in the tutorial?

FastAPI is a Python framework used to build APIs quickly and efficiently. In this tutorial, it is used to create a simple API that processes machine learning model predictions. FastAPI simplifies the process of writing the API code and running it locally.

How is the machine learning model used in the FastAPI example?

In the FastAPI example, a simple rule-based machine learning model is used. The model takes two inputs—age and sex—and predicts whether a person survived or not based on these inputs. This model is hosted through the FastAPI, allowing it to be accessed via an API.

What is the role of the 'predict' decorator in the FastAPI code?

The 'predict' decorator is used in FastAPI to define an endpoint for the API. It marks a function that will process the input parameters (like age and sex) and return the appropriate result, such as whether a person survived or not based on the machine learning model's logic.

Why is it not considered a good practice to pass data in the URL when making API requests?

Passing data in the URL (as seen in the 'GET' request) is not a good practice because URLs can be logged, cached, or exposed, leading to potential security risks. Sensitive information should instead be sent in the body of a request using a 'POST' method, ensuring better security and privacy.

What is the significance of using a POST request over a GET request in an API?

A POST request is used for securely sending data, especially sensitive information, in the body of the request rather than in the URL. This helps protect data from being exposed in logs or browser history, making it a more secure option for transmitting sensitive or large amounts of data.

What is the purpose of an API key and how does it enhance security?

An API key is a unique identifier used to authenticate requests made to an API. It helps control and monitor access, preventing unauthorized users from making requests to the API. API keys can also be used to limit the number of requests or charge for API usage.