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Hassan Shahzad
Hassan Shahzad

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How to Deploy a Python FastAPI Application to an EC2 Instance Using Amazon ECR

#webdev #programming #python #aws

Deploying a Python FastAPI application on the cloud ensures scalability, reliability, and performance. Amazon Web Services (AWS) provides powerful tools like Amazon EC2 (Elastic Compute Cloud) and Amazon ECR (Elastic Container Registry) to simplify the deployment process using Docker containers.

In this guide, we’ll walk you through step-by-step instructions to build, containerize, push, and run your FastAPI app on an AWS EC2 instance using ECR.

Why Use FastAPI with AWS EC2 and ECR?

FastAPI is one of the fastest-growing Python web frameworks because of its speed, simplicity, and built-in async support. Pairing it with AWS services like ECR and EC2 makes it easy to:

  • Store and manage Docker images securely in ECR.
  • Scale and run containerized applications on EC2.
  • Maintain flexibility with environment variables and networking configurations.
  • Set up a production-ready deployment with Nginx and custom domains.

Step 1: Prepare AWS CLI and Authenticate

Install AWS CLI

On your local machine, install the AWS CLI:

sudo apt update && sudo apt install awscli -y
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Configure AWS CLI

Enter your AWS credentials:

aws configure
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Provide:

  • AWS Access Key ID
  • AWS Secret Access Key
  • Default region name
  • Output format (optional)

Authenticate Docker with ECR

Run the login command (replace <region> and <account_id>):

aws ecr get-login-password --region <region> \
| docker login --username AWS --password-stdin <account_id>.dkr.ecr.<region>.amazonaws.com
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Step 2: Push the Docker Image to Amazon ECR

Build the Docker Image 

docker build -t <repository_name>:latest .
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Tag the Image for ECR 

docker tag <repository_name>:latest <account_id>.dkr.ecr.<region>.amazonaws.com/<repository_name>:latest
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Push the Image 

docker push <account_id>.dkr.ecr.<region>.amazonaws.com/<repository_name>:latest
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Step 3: Launch and Configure the EC2 Instance

  1. Launch an EC2 instance with desired CPU, memory, and storage.
  2. Attach a security group that allows:
  • SSH (TCP 22) → from your IP
  • HTTP (TCP 80) → from 0.0.0.0/0 (public access)

Step 4: Set Up the EC2 Instance

Connect to EC2 

ssh -i <key_pair.pem> ec2-user@<public-ip>
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Install Docker 

sudo apt update
sudo apt install docker.io -y
sudo systemctl enable docker
sudo systemctl start docker
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Install AWS CLI (if not installed) 

sudo apt install awscli -y
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Step 5: Pull and Run the Docker Image

Authenticate Docker with ECR

Run the same login command used on your local machine.

Pull the Image 

docker pull <account_id>.dkr.ecr.<region>.amazonaws.com/<repository_name>:latest
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Run the FastAPI Container 

docker run -d \
  --name fastapi_app \
  -p 80:8000 \
  -e FERNET_KEY="your_fernet_key" \
  -e DATABASE_URL="your_database_url" \
  <account_id>.dkr.ecr.<region>.amazonaws.com/<repository_name>:latest
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Step 6 (Optional): Set Up a Domain and Nginx

If you want to serve your app on a custom domain:

  1. Point your domain’s DNS A record to the EC2 public IP.
  2. Install Nginx: 
   sudo apt install nginx -y
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  1. Configure Nginx as a reverse proxy to your FastAPI app.
  2. Restart Nginx: 
   sudo systemctl restart nginx
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Step 7: Verify the Deployment

Visit:

http://<EC2_PUBLIC_IP>/docs
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You should see the FastAPI Swagger UI.

✅ If not, double-check:

  • EC2 security group rules
  • Docker container logs
  • Nginx configuration (if using a domain)

Conclusion

Deploying a Python FastAPI application on AWS EC2 with ECR gives you a secure, scalable, and production-ready environment. With Docker, you can ensure consistency across development and production.

Whether you’re building an MVP or scaling a SaaS application, this setup allows you to:

  • Manage images easily with ECR.
  • Deploy containers on demand with EC2.
  • Optionally enhance your deployment with Nginx and custom domains.

Now it’s your turn: Have you deployed FastAPI on AWS before? What challenges did you face? Share your experience in the comments!

Top comments (2)

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vatul16 profile image
Atul Vishwakarma •

If running a docker container then AWS ECS with Fargate will be a good choice…

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hassan_shahzad_086a39f774 profile image
Hassan Shahzad •

agreed but i have been free tier to just practice the resource as ECS is on paid aws with fargate feature so that why i go with ec2 just to keep it simple