How Do I Upload A File To S3 Using Boto3 In Python On Heroku

Are you a developer looking to harness the power of Heroku and Amazon S3 to seamlessly upload files to the cloud? You’re in the right place! In this comprehensive guide, we’ll walk you through the process of uploading a file to Amazon S3 using the Boto3 library in Python, all while hosted on the Heroku platform. By the end of this tutorial, you’ll have a deep understanding of the entire process and be ready to implement it in your own projects.

Setting the Stage – Heroku and Amazon S3

Before we dive into the code, let’s briefly discuss why you might want to use Heroku and Amazon S3 together. Heroku is a popular Platform-as-a-Service (PaaS) that allows developers to build, deploy, and scale web applications with ease. On the other hand, Amazon S3 (Simple Storage Service) is a highly scalable object storage service provided by Amazon Web Services (AWS).

Combining these two powerful services can help you create applications that store and serve files efficiently, whether they are user-uploaded images, documents, or any other type of data. So, without further ado, let’s get started!


Before we proceed, ensure that you have the following prerequisites in place:

  1. Heroku Account: You should have a Heroku account. If you don’t have one, sign up for free at Heroku’s website.
  2. AWS Account: You’ll need an AWS account to access Amazon S3. Sign up for an AWS account if you don’t have one already.
  3. Python and Boto3: Make sure you have Python installed on your local machine. You’ll also need to install the Boto3 library, which is the official AWS SDK for Python.

Setting Up Your Environment

Once you have the prerequisites ready, it’s time to set up your development environment. Here are the steps to follow:

  1. Install Python: If you haven’t already, download and install Python from the official Python website (
  2. Install Boto3: Use pip, Python’s package manager, to install Boto3: pip install boto3
  3. Configure AWS Credentials: You need to configure AWS credentials to interact with S3. You can do this by creating an IAM user with appropriate permissions and configuring your credentials using the AWS Command Line Interface (CLI) or environment variables.
  4. Heroku Account Setup: If you’re new to Heroku, follow their documentation to set up your Heroku account and install the Heroku CLI.

Writing Python Code

With your environment set up, it’s time to write some Python code. Here’s a step-by-step guide to uploading a file to S3 using Boto3 in Python:

  1. Import Boto3 and Configure S3 Client: In your Python script, import Boto3 and configure the S3 client using your AWS credentials. import boto3 s3 = boto3.client('s3')
  2. Specify S3 Bucket and File Details: Define the S3 bucket name where you want to upload the file and specify the file name and its local path. bucket_name = 'your-s3-bucket-name' file_name = 'example.txt' local_file_path = '/path/to/local/file.txt'
  3. Upload the File to S3: try: s3.upload_file(local_file_path, bucket_name, file_name) print(f'{file_name} uploaded successfully to {bucket_name}') except Exception as e: print(f'Error uploading {file_name}: {str(e)}')
  4. Running the Script: Execute your Python script. It will upload the specified file to your Amazon S3 bucket.

Deploying Your Application to Heroku

Now that you have successfully tested your code locally, it’s time to deploy your application to Heroku:

  1. Create a Heroku App: Using the Heroku CLI, create a new Heroku app. heroku create your-app-name
  2. Git Repository: Make sure your project is in a Git repository.
  3. Push to Heroku: Push your code to Heroku’s remote repository. git push heroku master
  4. Scaling: Scale your application to at least one dyno. heroku ps:scale web=1
  5. Open the App: You can now open your Heroku app in your web browser. heroku open

Frequently Asked Questions

How do I install Boto3 in my Heroku Python application?

To use Boto3 on Heroku, you should include it in your requirements.txt file. Add the following line to your requirements.txt:


    This will ensure that Heroku installs Boto3 when you deploy your application.

    How do I configure Boto3 to work with Amazon S3 on Heroku?

    You can configure Boto3 to work with Amazon S3 by setting up the AWS credentials and region. Heroku provides environment variables for these values. You can set them as follows:

         import os
         import boto3
         s3 = boto3.client(

      Ensure that you have added your AWS credentials and region to Heroku’s config vars.

      How do I upload a file to Amazon S3 using Boto3 on Heroku?

      You can upload a file to Amazon S3 using Boto3 by calling the put_object method on the S3 client. Here’s an example:

           s3.upload_file('local_file.txt', 'my-bucket', 's3_key_prefix/remote_file.txt')

        Replace 'local_file.txt' with the path to your local file, 'my-bucket' with your S3 bucket name, and 's3_key_prefix/remote_file.txt' with the desired S3 object key.

        How can I handle file uploads from users and then save them to S3 on Heroku?

        To handle file uploads from users and save them to S3 on Heroku, you can use a web framework like Flask or Django. First, you receive the uploaded file from the user, then save it temporarily on the Heroku server, and finally, use Boto3 to upload it to S3. Here’s a high-level overview:

          • Receive the file using a form in your web application.
          • Save the file to a temporary location on the Heroku server.
          • Use Boto3 to upload the file from the temporary location to S3.
          • Optionally, delete the temporary file on the Heroku server.

          How can I ensure security when uploading files to S3 from Heroku?

          To ensure security when uploading files to S3 from Heroku, follow these best practices:

            Use IAM (Identity and Access Management) roles or least-privilege AWS credentials for Heroku.

            Never hardcode your AWS credentials in your code; use environment variables or IAM roles.

            Set proper permissions on your S3 bucket and objects to control who can access them.

            Consider using server-side encryption (SSE) for added data security during storage.

            Implement authentication and authorization in your web application to control who can upload files to S3.

            In this article, we’ve covered the entire process of uploading a file to Amazon S3 using the Boto3 library in Python on the Heroku platform. By following the steps outlined here, you can efficiently manage and store files in the cloud, enhancing your web applications’ capabilities.

            Remember that this is just the beginning of what you can achieve with Heroku and Amazon S3. You can explore more advanced features, such as handling file permissions, implementing file versioning, and creating secure access policies to make your applications even more robust and secure.

            Now, armed with this knowledge, go ahead and leverage the power of Heroku and Amazon S3 to enhance your applications and deliver a seamless experience to your users. Happy coding!

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