Why Traffic Patterns Matter More Than Architecture Diagrams in Deployment Choices

A developer argues that two projects with identical architecture can still need very different deployments, because application features and traffic shape drive the decision. In one client project handling about 3,000 daily users, traffic was modest but came in predictable bursts around product releases and holidays. The author recommends matching the deployment to the traffic pattern, with a table comparing EC2 with Auto Scaling, ECS on Fargate, Lambda, ECS on EC2, and EKS. Before deploying, the post stresses that the application must be stateless, expose a health endpoint, account for database connection limits, and run scheduled jobs in only one place. The author ultimately chose EC2 with Auto Scaling and an Application Load Balancer, citing low steady-state cost, known spike dates, and existing Ansible roles.