Crosspost your latest content to social media directly from GitHub Actions. This action fetches URLs from a sitemap.xml or RSS/Atom feed, filters them by age, and posts them to your configured social networks using humanwhocodes/crosspost.

• Supports both sitemaps and RSS/Atom feeds.
• Crosspost to multiple networks in one go (Twitter/X, Mastodon, Bluesky, LinkedIn, etc.).
• Filter by age (since + since-unit) and by URL include/exclude patterns.
• Run in dry-run mode to safely preview what would be posted.
• Flexible failure strategies: stop on error or continue with other posts.
• Prefill messages with blog post metadata: use {description} and {tags} in your message template to automatically include the post's meta description and tags.

Start with dry-run: true to ensure you don’t flood your social networks with hundreds of posts on the first run. Once you confirm the filtering works as expected, remove dry-run or set it to false.

Run this action once a day at a time when your audience is most likely online — for example:

• 09:00 (morning commute)
• 17:00 (after work)

Example scheduler trigger:

on:
  schedule:
    - cron: '0 9 * * *'   # every day at 09:00 UTC

Here are the most important inputs (see action.yml for the full list):

The action accepts credentials as inputs and maps them to environment variables expected by crosspost. Examples:

• Mastodon

  • mastodon-access-token → MASTODON_ACCESS_TOKEN
  • mastodon-host → MASTODON_URL
  • more on configuration details.

• Twitter/X

  • twitter-access-token-key
  • twitter-access-token-secret
  • twitter-api-consumer-key
  • twitter-api-consumer-secret
  • more on configuration details.

• Bluesky

  • bluesky-host
  • bluesky-identifier
  • bluesky-password
  • more on configuration details.

• LinkedIn

  • linkedin-access-token
  • more on configuration details.

• Discord Bot

  • discord-bot-token
  • discord-channel-id
  • more on configuration details.

• Discord Webhook

  • discord-webhook-url
  • more on configuration details.

• Dev.to

  • devto-api-key
  • more on configuration details.

• Telegram

  • telegram-bot-token
  • telegram-chat-id
  • more on configuration details.

• Slack

  • slack-token
  • slack-channel
  • more on configuration details.

...and so on for other networks supported by crosspost.

Use GitHub secrets for these values.

This action can send Webmentions to notify other sites about your posts. There are two main approaches:

1. Endpoint-based webmentions (recommended for Brid.gy)

If you want to send webmentions through a centralized endpoint like Brid.gy:

• Set webmention-endpoint to the endpoint URL (e.g., https://brid.gy/publish/webmention).
• Set webmention-target-hosts to the social network targets (e.g., https://brid.gy/publish/bluesky, https://brid.gy/publish/mastodon).
• The action will send a webmention to the endpoint with your post as the source and each target as the target.

⚠️ Note: Webmention endpoints like Brid.gy ignore the message input. They fetch and parse your post HTML for microformats (h-entry, e-content, etc.) to determine the content. See Brid.gy's microformats documentation for details on how your post structure affects the result.

2. Dynamic webmentions (scan content for links)

To automatically notify all external URLs mentioned in your post content:

• Set webmention-scan-content: true.
• The action will scan your post's e-content (IndieWeb microformat) for external links and send webmentions to each unique URL.
• This is useful for notifying all sites you referenced in your posts.

Examples:

Example 1: Using Brid.gy endpoint

jobs:
  crosspost:
    runs-on: ubuntu-latest
    steps:
      - name: Run action-crosspost with Brid.gy webmentions
        uses: tgagor/action-crosspost@v1
        with:
          dry-run: true
          feed-url: https://example.com/rss.xml
          webmention-endpoint: https://brid.gy/publish/webmention
          webmention-target-hosts: >
            https://brid.gy/publish/bluesky
            https://brid.gy/publish/mastodon

Example 2: Scanning content for links and notifying them

jobs:
  crosspost:
    runs-on: ubuntu-latest
    steps:
      - name: Run action-crosspost with content scanning
        uses: tgagor/action-crosspost@v1
        with:
          feed-url: https://example.com/rss.xml
          webmention-scan-content: true

For more on webmentions, see Bridgy Webmentions, Brid.gy Microformats, or IndieWeb Webmention spec.

You can customize the message posted to social networks using the message input. The following placeholders are supported:

• {url}: The post URL.
• {description}: The meta description from the blog post (if available).
• {tags}: Tags extracted from the blog post (if available, formatted as hashtags).

Example:

with:
  message: |
    {description}
    {url}

    #blog {tags}

If the blog post contains a meta description and tags, these will be automatically inserted into the message.

jobs:
  crosspost:
    runs-on: ubuntu-latest
    steps:
      - name: Run action-crosspost on a test sitemap
        uses: tgagor/action-crosspost@v1
        with:
          dry-run: true
          feed-url: https://example.com/sitemap.xml
          since: '1'
          since-unit: day
          mastodon-access-token: ${{ secrets.MASTODON_ACCESS_TOKEN }}
          mastodon-host: mastodon.social
          exclude-urls: |
            https://example.com/
            https://example.com/author*
            https://example.com/tags/*
            https://example.com/categories/*
            https://example.com/posts/*
            https://example.com/about/
          filter-urls: |
            /blog/

jobs:
  crosspost:
    runs-on: ubuntu-latest
    steps:
      - name: Run action-crosspost on a test RSS feed
        uses: tgagor/action-crosspost@v1
        with:
          dry-run: true
          feed-url: https://example.com/index.xml
          since: '1'
          since-unit: week
          twitter-api-key: ${{ secrets.TWITTER_API_KEY }}
          twitter-api-secret: ${{ secrets.TWITTER_API_SECRETS }}$
          exclude-urls: |
            https://example.com/
            https://example.com/about/
          filter-urls: |
            book
          message: |
            {description}
            {url}

            #blog {tags}

Resulting post message example:

How to automate your blog crossposting with GitHub Actions.
https://example.com/blog/automate-crossposting

#blog #automation #github

• Sitemaps may mark pages as updated, so posts could appear again even if they were published earlier.

  • If you want to avoid reposting updated content, prefer using RSS/Atom feeds, which rely on the original publication date.

• Always begin with dry-run: true to validate your filtering before posting.

• Use exclude-urls and filter-urls to fine-tune which links should actually be posted.