--- title: Using the Redoc Docker image --- # Using the Redoc Docker image Redoc is available as a pre-built Docker image in [Docker Hub](https://hub.docker.com/r/redocly/redoc/). If you have [Docker](https://docs.docker.com/get-docker/) installed, pull the image with the following command: ```docker docker pull redocly/redoc ``` Then run the image with the following command: ```docker docker run -p 8080:80 redocly/redoc ``` The preview starts on port 8080, based on the port used in the command, and can be accessed at `http://localhost:8080`. To exit the preview, use `control+C`. By default Redoc starts with a demo Swagger Petstore OpenAPI definition located at http://petstore.swagger.io/v2/swagger.json. You can update this URL using the environment variable `SPEC_URL`. For example: ```bash docker run -p 8080:80 -e SPEC_URL=https://api.example.com/openapi.json redocly/redoc ``` ## Using a Dockerfile You can also create a Dockerfile with some predefined environment variables. Check out a sample [Dockerfile](https://github.com/Redocly/redoc/blob/master/config/docker/Dockerfile) in our code repo.