GScan is a tool for validating Ghost themes. It produces detailed reports of issues where themes need to be modified in order to be compatible with a specific version.

It is actively capable of dealing with the current and last major versions of Ghost (v1-v6).

GScan works on a system of rules. Each rule has a way to check whether it passes or fails and has help content which describes how to fix it. Each rule is also marked with an error level:

- Errors: issues that will cause your theme to not work properly. These must be fixed.
- Warnings: these are usually related to deprecated features. These should be fixed.
- Recommendations: these are advisories about best practice. Fixing these will improve your theme.
- Features: detected features which may impact on compatibility. Nothing to do!

In addition, an error can be marked as fatal. A fatal error means, left unchecked a Ghost publication would throw 500 errors on certain pages because of the detected out-of-date or erroneous code.

Usage

There are 4 ways to use gscan to validate your theme:

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Gscan is pre-installed in Ghost. If there are theme errors, Ghost will show them on boot in the console logs and in the UI (Ghost Admin).

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Visit https://gscan.ghost.org and upload your zip to our online version of Gscan.

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Install using yarn / npm:

yarn global add gscan / npm install -g gscan

To run a local directory through the checks:

gscan /path/to/theme/directory

To run a local zip file through the checks:

gscan /path/to/theme.zip -z

By default, GScan scans themes for the latest Ghost version compatibility. You can also specify a Ghost version by using the following parameters (for Ghost 1.0, 2.0, 3.0, 4.0, 5.0 and 6.0):

--v1 or -1
--v2 or -2
--v3 or -3
--v4 or -4
--v5 or -5
--v6 or -6 (default) or --canary

Examples:

gscan /path/to/theme.zip -z -1 - scan a theme in a zip file for Ghost 1.0 compatibility
gscan /path/to/theme/directory --v2 - can a theme in a directory for Ghost 2.0 compatibility
gscan /path/to/theme/directory - scan a theme for Ghost 6.0 compatibility

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Install using yarn/npm and then:

``js
var gscan = require('gscan');

gscan.checkZip({
path: 'path-to-zip',
// Pass in a folder to check
// if you need to check the theme for a different
// major Ghost version, you can pass it. Currently
// v1, v2, v3, v4, v5 and v6 are supported. Default is
// the latest Ghost version 6.0:
// checkVersion: 'v6',
name: 'my-theme'
}).then(function (result) {
console.log(result);
}).catch(function(err) {
console.log(err);
});
`

Development

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- Either dev mode: yarn dev
- Or standard server: yarn start
- View: http://localhost:2369

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- zip file: ./bin/cli.js -z /path/to/your/theme.zip
- directory: ./bin/cli.js /path/to/directory

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(Core team only)

- yarn ship`

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When developing new rules or testing gscan following tools are great to have in the toolbelt:
- astexplorer - absolutely awesome Handlebars AST fiddler, helpful when testing out new ideas and exploring what's possible through AST parser;

To Do

- Support for running the checks against a GitHub repository
- Many, many more checks
- Detailed advice for each check/result
- Compatibility report
- Feature listing

Copyright & License

Copyright (c) 2013-2025 Ghost Foundation - Released under the MIT license. Ghost and the Ghost Logo are trademarks of Ghost Foundation Ltd. Please see our trademark policy for info on acceptable usage.