Uploading File API [FastAPI]

Creating APIs to upload files

Uploading File API [FastAPI]


When interfacing with CMS platforms or any SaaS products, the necessity often arises to accept user-provided files. Historically, a common, albeit rudimentary approach, has been to instruct users to upload files to external cloud storage platforms such as Google Drive, subsequently providing a link for integration.

However, embracing modern methodologies, we can leverage the capabilities of FastAPI, a Python package, to develop our own API for seamlessly handling file uploads directly to our backend infrastructure.

This approach not only enhances user experience by streamlining the process of file submission but also offers greater control and security over data management within our system. By integrating FastAPI into our workflow, we empower our application with the ability to directly receive and store user-provided files, facilitating a more efficient and robust solution for file handling requirements.

The Plan ๐Ÿš€

Our proposed endeavor entails the development of a backend application, supplemented by the creation of a POST API endpoint. This endpoint will be engineered to receive input files from users, subsequently facilitating the seamless storage of these files within a designated directory.

This initiative aims to enhance user interaction by providing a streamlined mechanism for file submission, thereby optimizing the overall user experience. By establishing a structured backend infrastructure and implementing a robust API, we endeavor to fortify data management processes, fostering efficiency and reliability within our system.

Creating the FastAPI Application

from fastapi import FastAPI, File, UploadFile
from pydantic import BaseModel
import os

app = FastAPI()

class FileUploadRequest(BaseModel):
    description: str = "File upload request"

async def upload_files(request: FileUploadRequest, files: list[UploadFile] = File(...)):
    for file in files:
        file_path = os.path.join(os.getcwd(), "uploaded_files", file.filename)
        async with open(file_path, "wb") as f:
            f.write(await file.read())

    return {"message": "Files uploaded successfully"}

Run the APP

uvicorn main:app --host --port 8000


The provided code establishes a FastAPI application equipped with a POST endpoint /uploadfiles/ tailored for handling file uploads. It defines a request body model named FileUploadRequest, encapsulating the description attribute to denote the purpose of the file upload request.

Upon receiving a POST request to /uploadfiles/, the endpoint anticipates a list of UploadFile objects representing the files to be uploaded. Iterating through each file, the code constructs a file path by amalgamating the current working directory with the directory named "uploaded_files" and the filename provided by the user. Asynchronous file operations are employed to asynchronously write the file contents to the specified file path.

This implementation adheres to modern asynchronous programming paradigms, leveraging FastAPI's capabilities for efficient handling of HTTP requests. Additionally, it promotes modularisation and maintainability by utilising Python's standard libraries for file operations and path handling.


In conclusion, our exploration into leveraging FastAPI for efficient file handling within backend applications has underscored the significance of embracing modern methodologies in software development. By transitioning away from conventional approaches reliant on external cloud storage platforms, we've demonstrated the power of crafting bespoke solutions tailored to our specific requirements.

The development of a FastAPI-based API endpoint for file uploads not only streamlines the submission process but also affords us greater autonomy and control over our data management workflows. Through the seamless integration of FastAPI into our backend infrastructure, we've empowered our application to directly receive and store user-provided files, thereby enhancing both user experience and data security.

Moving forward, the adoption of FastAPI, coupled with best practices in asynchronous programming, promises to revolutionize how we handle file uploads and other data interactions within our applications. By staying abreast of advancements in technology and embracing innovative solutions, we position ourselves to meet the evolving needs and expectations of our users while ensuring the robustness and scalability of our systems.