All-in-one Collaborative API Development Platform

API Design

API Documentation

API Debugging

API Mock

API Automated Testing

Sign up for free

What is FastAPI

Start for free
Home / Basic Knowledge / What is FastAPI

What is FastAPI

FastAPI is a modern, fast (high-performance), web framework for building APIs with Python 3.7+ based on standard Python type hints. It is designed to be easy to use and to provide high performance for building APIs.

FastAPI is a modern, fast (high-performance), web framework for building APIs with Python 3.7+ based on standard Python type hints. It is designed to be easy to use and to provide high performance for building APIs. FastAPI is built on top of Starlette, which is a lightweight ASGI (Asynchronous Server Gateway Interface) framework. This allows FastAPI to take advantage of the asynchronous capabilities of Python, making it highly efficient and capable of handling high loads.


Key Features of FastAPI

One of the key features of FastAPI is its performance. FastAPI is built on top of Starlette, which is a high-performance asynchronous framework. It leverages the power of Python's type hints to provide automatic data validation, serialization, and documentation generation. This allows developers to write code that is both efficient and easy to understand.

FastAPI also supports asynchronous programming, which allows for better scalability and responsiveness. It uses the async and await keywords to handle asynchronous operations, such as making HTTP requests or querying databases, without blocking the execution of other tasks. This makes it ideal for building highly concurrent applications that can handle a large number of requests.

Another key feature of FastAPI is its automatic documentation generation. FastAPI leverages the power of Python's type hints to automatically generate interactive API documentation. This documentation includes information about the request and response models, as well as the available endpoints and their parameters. It also provides a user-friendly interface for testing and exploring the API.

key feature of FastAPI

FastAPI also provides built-in support for handling common tasks, such as authentication and authorization. It supports various authentication mechanisms, such as OAuth2 and JWT, and provides decorators and middleware to handle authorization logic. This makes it easy to secure your API and protect sensitive data.

In addition, FastAPI has excellent support for handling data validation and serialization. It uses Python's type hints to automatically validate incoming requests and convert them to the appropriate data types. This helps prevent common programming errors and ensures that your API always receives valid data.

FastAPI also provides a powerful dependency injection system, which allows you to easily manage and share resources across different parts of your application. This makes it easy to organize your code and write reusable components.

How FastAPI Differs from Other Frameworks

Key differences of FastAPI:

Performance: Built on Starlette, an asynchronous web framework known for high performance, FastAPI can handle high loads and process requests quickly, making it ideal for building high-performance APIs.

Type Hints: FastAPI utilizes Python type hints for automatic data validation and serialization. Defining input and output data types with type hints helps catch errors early in development and improves code reliability and maintainability.

Asynchronous Programming: With asyncio as its foundation, FastAPI supports asynchronous programming. Using async and await syntax, you can handle concurrent requests and perform I/O-bound operations without blocking the event loop, enabling efficient and scalable code.

Automatic API Documentation: FastAPI automatically generates interactive API documentation using the OpenAPI standard. Documentation stays in sync with the code based on type hints and function signatures, making it easy to maintain.

Dependency Injection: FastAPI supports dependency injection, allowing easy management of dependencies and code decoupling. This enables writing testable and maintainable code by defining and injecting dependencies into API endpoints and other application components.

Getting Started with FastAPI

To get started with FastAPI, you will need to install it first. FastAPI can be installed using pip, the Python package installer. Open your terminal or command prompt and run the following command:

pip install fastapi

Once FastAPI is installed, you can start building your API. The first step is to import the necessary modules and create an instance of the FastAPI class. Here's an example:

from fastapi import FastAPI

app = FastAPI()

Next, you can define your API routes using FastAPI's decorator-based syntax. A route is a URL pattern that the API will respond to. You can define routes for different HTTP methods such as GET, POST, PUT, DELETE, etc. Here's an example of defining a simple route:

def hello():
    return {"message": "Hello, World!"}

In this example, we define a GET route /hello that returns a JSON response with a message "Hello, World!".

FastAPI also supports path parameters, query parameters, and request bodies. You can define these parameters using Python type hints. Here's an example of defining a route with path parameters and query parameters:

def read_item(item_id: int, q: str = None):
    return {"item_id": item_id, "q": q}

In this example, the item_id is a path parameter and q is a query parameter. FastAPI automatically validates the types of these parameters and generates the appropriate documentation.

FastAPI also supports automatic generation of OpenAPI and JSON Schema documentation. You can access the automatically generated documentation by visiting the /docs route in your browser. This documentation provides detailed information about your API routes, including the expected request and response models.

To run your FastAPI application, you can use the uvicorn server. Uvicorn is a lightning-fast ASGI server implementation, and it is recommended for running FastAPI applications. You can install uvicorn using pip:

pip install uvicorn

Once installed, you can start your FastAPI application by running the following command:

uvicorn main:app --reload

In this command, main refers to the Python file where you created your FastAPI instance, and app is the name of the FastAPI instance.

FastAPI also provides additional features such as dependency injection, OAuth2 authentication, and WebSocket support. These features make it easy to build complex and secure APIs.

Overview of Apidog

After introducing FastAPI's features, it's time to talk about Apidog and its additional functionalities:

Apidog takes API development to the next level by offering a wide range of advanced features, including WebSocket support, automated testing, and mock server capabilities.

WebSocket Support: Apidog seamlessly integrates WebSocket support, allowing real-time bidirectional


communication between clients and servers. With WebSocket support, you can build interactive and efficient applications that require constant communication and updates.

Automated Testing: Apidog simplifies the testing process with its built-in automation testing module. You can easily create test scenarios, reference API cases, and group them together for execution. This comprehensive testing capability ensures that your APIs function as expected, enhancing the reliability of your applications.

Mock Server: Apidog provides an intelligent Smart Mock Server that responds to requests with API responses defined in your API definitions. This means you can conveniently develop front-end interfaces using the mock environment even before the actual API development is completed.

Enhanced API Documentation: Apidog goes beyond basic documentation by offering a fully interactive and visually appealing API documentation platform. It automatically generates API documentation based on your API definitions, keeping the documentation up-to-date with your code changes.

Streamlined Collaboration: Apidog supports team collaboration, making it easy to work on APIs together. You can invite team members, assign roles, and share API projects securely, promoting efficient collaboration throughout the development process.

With Apidog's comprehensive set of features, you can elevate your API development, testing, and collaboration to new heights, ensuring high-quality and robust APIs for your applications.

Apidog - An integrated platform for API design, debugging, development, mock, and testing
REAL API Design-first Development Platform. Design. Debug. Test. Document. Mock. Build APIs Faster & Together.