Skip to content
link

GitHub Action

markdown-link-check

1.0.14 Pre-release
Use latest version
link

markdown-link-check

Check if all links are valid in markdown files

Installation

Copy and paste the following snippet into your .yml file.

- name: markdown-link-check
  uses: gaurav-nelson/github-action-markdown-link-check@1.0.14
Learn more about this action in gaurav-nelson/github-action-markdown-link-check
Choose a version

GitHub Action - Markdown link check 🔗✔️

GitHub Marketplace

This GitHub action checks all Markdown files in your repository for broken links. (Uses tcort/markdown-link-check)

How to use

  1. Create a new file in your repository .github/workflows/action.yml.

  2. Copy-paste the following workflow in your action.yml file:

    name: Check Markdown links
    
    on: push
    
    jobs:
      markdown-link-check:
        runs-on: ubuntu-latest
        steps:
        - uses: actions/checkout@master
        - uses: gaurav-nelson/github-action-markdown-link-check@v1

Real-life usage samples

Following is a list of some of the repositories which are using GitHub Action - Markdown link check.

  1. netdata
  2. GoogleChrome/lighthouse (Weekly cron job)
  3. tendermint/tendermint
  4. pyroscope-io/pyroscope

If you are using this on production, consider buying me a coffee .

Configuration

Custom variables

You customize the action by using the following variables:

Variable Description Default value
use-quiet-mode Specify yes to only show errors in output. no
use-verbose-mode Specify yes to show detailed HTTP status for checked links. no
config-file Specify a custom configuration file for markdown-link-check. You can use it to remove false-positives by specifying replacement patterns and ignore patterns. mlc_config.json
folder-path By default the github-action-markdown-link-check action checks for all markdown files in your repository. Use this option to limit checks to only specific folders. Use comma separated values for checking multiple folders. .
max-depth Specify how many levels deep you want to check in the directory structure. The default value is -1 which means check all levels. -1
check-modified-files-only Use this variable to only check modified markdown files instead of checking all markdown files. The action uses git to find modified markdown files. Only use this variable when you run the action to check pull requests. no
base-branch Use this variable to specify the branch to compare when finding modified markdown files. master
file-extension By default the github-action-markdown-link-check action checks files in your repository with the .md extension. Use this option to specify a different file extension such as .markdown or .mdx. .md
file-path Specify additional files (with complete path and extension) you want to check. Use comma separated values for checking multiple files. See Check multiple directories and files section for usage. -

Sample workflow with variables

name: Check Markdown links

on: push

jobs:
  markdown-link-check:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@master
    - uses: gaurav-nelson/github-action-markdown-link-check@v1
      with:
        use-quiet-mode: 'yes'
        use-verbose-mode: 'yes'
        config-file: 'mlc_config.json'
        folder-path: 'docs/markdown_files'
        max-depth: 2

Scheduled runs

In addition to checking links on every push, or pull requests, its also a good hygine to check for broken links regularly as well. See Workflow syntax for GitHub Actions - on.schedule for more details.

Sample workflow with scheduled job

name: Check Markdown links

on:
  push:
    branches:
    - master
  schedule:
  # Run everyday at 9:00 AM (See https://pubs.opengroup.org/onlinepubs/9699919799/utilities/crontab.html#tag_20_25_07)
  - cron: "0 9 * * *"

jobs:
  markdown-link-check:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@master
    - uses: gaurav-nelson/github-action-markdown-link-check@v1
      with:
        use-quiet-mode: 'yes'
        use-verbose-mode: 'yes'
        config-file: 'mlc_config.json'
        folder-path: 'docs/markdown_files'

Disable check for some links

You can include the following HTML comments into your markdown files to disable checking for certain links in a markdown document.

  1. <!-- markdown-link-check-disable --> and <!-- markdown-link-check-enable-->: Use these to disable links for all links appearing between these comments.
    • Example:
      <!-- markdown-link-check-disable -->
      ## Section
      
      Disbale link checking in this section. Ignore this [Bad Link](https://exampleexample.cox)
      <!-- markdown-link-check-enable -->
  2. <!-- markdown-link-check-disable-next-line --> Use this comment to disable link checking for the next line.
  3. <!-- markdown-link-check-disable-line --> Use this comment to disable link checking for the current line.

Check only modified files in a pull request

Use the following workflow to only check links in modified markdown files in a pull request.

When you use this variable, the action finds modififed files between two commits:

  • latest commit in you PR
  • latest commit in the master branch. If you are suing a different branch to merge PRs, specify the branch using base-branch.

NOTE: We can also use GitHub API to get all modified files in a PR, but that would require tokens and stuff, create an issue or PR if you need that.

on: [pull_request]
name: Check links for modified files
jobs:
  markdown-link-check:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@master
    - uses: gaurav-nelson/github-action-markdown-link-check@v1
      with:
        use-quiet-mode: 'yes'
        use-verbose-mode: 'yes'
        check-modified-files-only: 'yes'

Check multiple directories and files

on: [pull_request]
name: Check links for modified files
jobs:
  markdown-link-check:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@master
    - uses: gaurav-nelson/github-action-markdown-link-check@v1
      with:
        use-quiet-mode: 'yes'
        folder-path: 'md/dir1, md/dir2'
        file-path: './README.md, ./LICENSE, ./md/file4.markdown'

Too many requests

Use retryOn429, retry-after, retryCount, and fallbackRetryDelay in your custom configuration file. See https://github.com/tcort/markdown-link-check#config-file-format for details.

Or mark 429 status code as alive:

{
  "aliveStatusCodes": [429, 200]
}

GitHub links failure fix

Use the following httpHeaders in your custom configuration file to fix GitHub links failure.

{
  "httpHeaders": [
    {
      "urls": ["https://github.com/", "https://guides.github.com/", "https://help.github.com/", "https://docs.github.com/"],
      "headers": {
        "Accept-Encoding": "zstd, br, gzip, deflate"
      }
    }
  ]
}

Example Usage

Consider a workflow file that checks for the status of hyperlinks on push to the master branch,

name: Check .md links

on:
  push: [master]

jobs:
  markdown-link-check:
    runs-on: ubuntu-latest
    # check out the latest version of the code
    steps:
    - uses: actions/checkout@v3

    # Checks the status of hyperlinks in .md files in verbose mode
    - name: Check links
      uses: gaurav-nelson/github-action-markdown-link-check@v1
      with:
        use-verbose-mode: 'yes'

A file test.md exists, containing

image

On running the workflow described above, the output shown below is obtained

image

Versioning

GitHub Action - Markdown link check follows the GitHub recommended versioning strategy.

  1. To use a specific released version of the action (Releases):
    - uses: gaurav-nelson/github-action-markdown-link-check@1.0.1
  2. To use a major version of the action:
    - uses: gaurav-nelson/github-action-markdown-link-check@v1
  3. You can also specify a specific commit SHA as an action version:
    - uses: gaurav-nelson/github-action-markdown-link-check@44a942b2f7ed0dc101d556f281e906fb79f1f478

Buy me a coffee.