Captain Definition Schema

A file named captain-definition at the deployment root tells CapRover what to deploy. Its source interface contains schemaVersion and four possible deployment selectors.

Field	Type	Meaning
schemaVersion	number	Required; the current parser accepts 2.
imageName	string	Pull and deploy an existing Docker image.
dockerfilePath	string	Path to a Dockerfile in the deployment archive. Parent-directory paths are rejected.
dockerfileLines	string[]	Lines of an inline Dockerfile.
templateId	string	Use a built-in Dockerfile template.

Provide exactly one of the four selectors. The parser rejects zero or multiple selectors.

{"schemaVersion": 2, "imageName": "nginx:stable-alpine"}

imageName deployments cannot be rebuilt from source without a new definition. For an example with a Dockerfile, see Static / React.

Built-in templates and versions

templateId has the form NAME/VERSION, for example:

{"schemaVersion":2,"templateId":"node/24"}

CapRover's template definitions generate Dockerfiles using these official image tags:

NAME	Base image for NAME/VERSION
node	node:VERSION-alpine
php	php:VERSION-apache
python-django	python:VERSION-alpine
ruby-rack	ruby:VERSION-alpine

• For node/24, the resulting base is node:24-alpine.
• The tag must exist in the relevant upstream image registry, and a major-only tag can move as that image is updated.
• Template-specific Dockerfile instructions are in CapRover's dockerfiles directory.
• Inspect them before relying on a template's framework assumptions or changing versions.
• A repository-owned Dockerfile lets you pin an exact image tag or digest and control the build for other frameworks.