A Docker image for a Next.js application is a self-contained package that includes the application code, runtime environment, libraries, and system tools required to run the app. It provides a consistent, immutable snapshot of your application’s environment, ensuring that it behaves the same way regardless of where it is deployed.
In Docker terminology, if an image is analogous to a class in object-oriented programming, then a container is like an instance of that class. Containers are the live, running instances created from Docker images.
The main purpose of using Docker with Next.js is to facilitate consistent, portable deployments. By building a Docker image of your Next.js application, you ensure that it runs in the same way across different environments. Once the image is created, you can deploy it to various environments, such as development, staging, or production, with confidence that the application will function consistently.