OKF Validator: check an Open Knowledge Format file

Validator quick actions

What this validator checks

• Whether a simple YAML frontmatter block exists at the top of the Markdown file.
• Whether the required type field is present.
• Whether recommended guide fields such as title, description, and tags are present.
• Whether tags uses an inline array such as [okf, validator, markdown].
• Whether the Markdown body exists after the frontmatter block.
• Whether relative Markdown links should be manually reviewed in the real bundle.

Repair one OKF file

Use this page when you need to repair one pasted Markdown file. Use the OKF Folder Validator when you need to check `index.md`, duplicate resources, and relative links across a local bundle.

• Single-file check: frontmatter, required type, recommended metadata, body, and local link warnings.
• Folder check: multiple Markdown files, bundle entry point, duplicate resource values, and unresolved relative links.
• Both checks are browser-only helpers and do not prove factual accuracy or official conformance.

Required OKF fields

Required field

This validator treats type as the required OKF field.

• type: the concept category.

Recommended fields

These fields are not required, but they make snippets, previews, indexes, and bundle review easier.

• title: the readable file name.
• description: a one-sentence summary.
• tags: an inline array for grouping related files.
• resource: the canonical source URL, URN, or stable identifier.

v0.2 field review

generated, verified, status, stale_after, and sources can help an owner review a file. This browser helper does not verify those fields or turn them into official requirements.

Example OKF file

Use this starter file to test the validator, then read the OKF file example guide for field notes and common mistakes.

---
type: Website Page
title: Open Knowledge Format Validator
description: A browser-only tool that checks basic OKF frontmatter fields.
resource: https://openknowledgeformat.online/okf-validator/
tags: [okf, validator, markdown]
timestamp: 2026-06-21T00:00:00Z
---

# Purpose

This page helps users test whether a Markdown document includes the fields expected by this guide.

What this validator can and cannot prove

The validator runs in the browser and does not upload pasted Markdown to this website. It checks one file's structure, not source truth, official status, full OKF conformance, or AI visibility. Do not paste restricted records into any online page unless your own policy allows it.

Next steps after a single-file check

• OKF file example for a full Markdown and YAML starter.
• OKF YAML frontmatter for required and recommended fields.
• OKF Folder Validator for checking local multi-file bundles.
• Common OKF validation errors for repair steps.
• Validate OKF Bundle before publishing a folder.
• OKF Templates for copy-ready starter files.