Docker

Docker is a platform for building, sharing and running applications in containers. It is made by Docker, Inc. A container packages an application together with its dependencies, so the same image can run on a laptop, a test server or a cloud host without the "works on my machine" problems that come from different environments.

The open-source Docker Engine uses a client-server design: the docker client sends commands over a REST API to the Docker daemon, which builds images and runs containers, networks and volumes. Images are stored in registries, and Docker Hub is the default public registry. Docker Desktop bundles the engine, the CLI, Docker Compose and an optional Kubernetes cluster into one application for Mac, Windows and Linux.

Key features

• Images and containers. Images are read-only, layered templates built from a Dockerfile; containers are isolated, runnable instances of those images that you can start, stop and delete.
• Docker Desktop. A single installable application for Mac, Windows and Linux that includes the daemon, the client, Compose and Kubernetes.
• Docker Compose. Defines and runs multi-container applications, such as a web app with its database and cache, from one file.
• Docker Build. Builds custom images from Dockerfiles; images are made of layers, which keeps storage and transfers efficient.
• Docker Hub. A registry for publishing and pulling images, with public and private repositories.
• Docker Scout and Hardened Images. Docker Scout is included with a set number of enabled repositories per plan. Docker Hardened Images are minimal base images with SBOMs and SLSA Build Level 3 provenance; the Community tier is free under Apache 2.0.
• Testcontainers Cloud. Paid plans include monthly runtime minutes for running Testcontainers-based integration tests in the cloud.

Who it is for

Docker suits individual developers who want a repeatable local environment, small teams that ship web services, and larger engineering organisations that standardise builds and deployments on containers. It is common in CI pipelines, microservice architectures, local database and queue setups, and training environments. Platform and security teams in larger companies use the Business plan for single sign-on, SCIM provisioning and control over which images and registries developers may use.

Pricing at a glance

• Personal: $0 for one user, with 1 private repository, 1 Docker Scout-enabled repository and 100 Docker Hub pulls per hour.
• Pro: $11 per month, or $9 per month billed annually, for one user; unlimited Docker Hub pulls, 2 Scout-enabled repositories and 100 Testcontainers Cloud minutes a month.
• Team: $16 per user per month, or $15 billed annually, for up to 100 users; adds role-based access control, audit logs, unlimited private and Scout-enabled repositories and 500 Testcontainers Cloud minutes.
• Business: $24 per user per month with no user cap; adds SSO, SCIM, Image and Registry Access Management, hardened Docker Desktop and 1,500 Testcontainers Cloud minutes.

Docker Hardened Images Select starts at $5,000 per repository; Enterprise is priced on request. Prices as checked on 7 October 2026; confirm on the vendor's pricing page.

Things to consider

• Docker Desktop is free only for personal use, education, non-commercial open-source projects and small businesses with fewer than 250 employees and less than $10 million in annual revenue. Larger organisations and government entities need a paid subscription (see the Docker Desktop licence page).
• The licensing of the open-source Docker Engine and Moby projects is separate from Docker Desktop, so servers that run only the engine are not covered by the Desktop subscription terms.
• The free Personal plan limits Docker Hub to 100 pulls per hour, which busy CI pipelines can reach.
• Containers share the host kernel, so they isolate less strongly than virtual machines; production setups still need image scanning, least-privilege settings and patching.

Getting started

1. Read the Docker overview to learn the image, container and registry concepts.
2. Install Docker Desktop, or Docker Engine on a Linux server.
3. Run a public image from Docker Hub to check the installation.
4. Write a Dockerfile for your own application and build an image.
5. Describe the app and its services in a Compose file and start them together.