docker-selenium

Selenium is a well-known tool for automating web browsers, meaning it can make Chrome, Firefox, or Edge open pages, click buttons, and fill out forms without a human sitting at the keyboard. This is used primarily for automated testing: you write tests that describe what a real user would do in your web app, and Selenium runs those actions in an actual browser to check that everything works correctly.

This project provides pre-packaged Docker images that make it straightforward to run Selenium Grid in a containerized environment. Docker is a system that lets you package software along with all its dependencies into a self-contained unit that runs consistently on any machine. Selenium Grid is the part of Selenium that lets you run many browser sessions in parallel across multiple machines, rather than testing one browser at a time on a single computer.

The images come in several configurations. A standalone image includes everything in one container and is suitable for small-scale use or local development. A hub-and-node setup splits coordination from execution, where the hub receives test requests and routes them to node containers, each of which runs a specific browser. There is also a fully distributed mode for larger deployments where even the hub's internal components run as separate containers.

For teams already using Kubernetes (a system for managing large numbers of containers across a cluster of machines), the project provides a Helm chart, which is a packaged configuration that automates the deployment of the entire Selenium Grid setup into Kubernetes. There is also support for auto-scaling based on test demand using a tool called KEDA.

Additional features include optional video recording of test sessions, the ability to set screen resolution and browser language, headless mode (running the browser without a visible window), and configuration for secure connections. The images are published to Docker Hub and maintained by the Selenium community under the Apache 2.0 license. The full README is longer than what was shown.