Jekyll page schema

Built-in id: jekyll:page:4.4

Published at https://hawkeyexl.github.io/manni/schemas/jekyll/4.4.json. A $schema that names this URL resolves to the bundled copy, with no network call.

jekyll:page:4.4 checks the front matter Jekyll 4.4 reads from a .md or .markdown page. It requires nothing. In Jekyll it is the presence of the --- block, not its contents, that marks a file for processing. It is one of the platform schemas, which say what a generator accepts rather than what your team agreed.

Property	Value
Id	jekyll:page:4.4
Title	Jekyll front matter v4.4
Files it fits	.md, .markdown
Dialect	Draft 2020-12
Required fields	None
Additional properties	Allowed (additionalProperties: true)
Reference kind	builtin
On by default	No
Upstream reference	Front matter
JSON	jekyll/4.4.json

Use it

Jekyll keeps pages at the repo root, so an override names the directory the schema covers:

manni.config.yaml

meta:
  overrides:
    - files: "_posts/**"
      schemas:
        - jekyll:page:4.4

For a one-off run, pass the id directly:

manni meta validate _posts/ -s jekyll:page:4.4

Fields

Deliberately the smallest built-in, because Jekyll’s own contract is small: three global variables and four more for posts.

Field	Type	Notes
layout	string | null	null or none suppresses the layout, so null is allowed.
permalink	string	Overrides the built URL.
published	boolean	false keeps the document out of the site.
date	string	Overrides the date parsed from the file name.
category, categories, tags	string | string array	A YAML list or a space-separated string.

The check worth having is published. published: "false" is a string, every string is truthy, and the post you meant to hold back goes live.

Additional properties

Allowed. A key Jekyll does not define passes unchecked.

Your `nav_order` is not Jekyll's

Most keys in a real Jekyll site come from a theme or a plugin, not from Jekyll: nav_order, parent, has_children are just-the-docs; redirect_from is jekyll-redirect-from. None are described here, and all pass as unknown keys. Pair this schema with one of your own if you want them checked.

Example page

A post carrying every variable Jekyll defines. This is test/fixtures/platform/jekyll-valid.md, and it passes.

_posts/2026-06-25-deploy.md

---
layout: post
permalink: /guides/deploy/
published: true
date: 2026-06-25 09:30:00 +0200
categories: [guides, deploy]
tags: ci
---

A common mistake

A quoted published flag is a string, and Jekyll publishes the post anyway:

test/fixtures/platform/jekyll-bad-published.md

---
layout: post
published: "false"
---

✗ test/fixtures/platform/jekyll-bad-published.md
    /published  must be boolean  (line 3)  [jekyll:page:4.4]

1 file checked, 0 passed, 1 failed, 1 error

Drop the quotes, so the value is the boolean false.