Substack Downloader

Simple CLI tool to download one or all the posts from a Substack blog.

Installation

Downloading the binary

Check in the releases page for the latest version of the binary for your platform. We provide binaries for Linux, MacOS and Windows.

Using Go

go install github.com/alexferrari88/sbstck-dl

Your Go bin directory must be in your PATH. You can add it by adding the following line to your .bashrc or .zshrc:

export PATH=$PATH:$(go env GOPATH)/bin

Usage

Usage:
  sbstck-dl [command]

Available Commands:
  download    Download individual posts or the entire public archive
  help        Help about any command
  list        List the posts of a Substack
  version     Print the version number of sbstck-dl

Flags:
      --after string             Download posts published after this date (format: YYYY-MM-DD)
      --before string            Download posts published before this date (format: YYYY-MM-DD)
      --cookie_name cookieName   Either substack.sid or connect.sid, based on your cookie (required for private newsletters)
      --cookie_val string        The substack.sid/connect.sid cookie value (required for private newsletters)
  -h, --help                     help for sbstck-dl
  -x, --proxy string             Specify the proxy url
  -r, --rate int                 Specify the rate of requests per second (default 2)
  -v, --verbose                  Enable verbose output

Use "sbstck-dl [command] --help" for more information about a command.

Downloading posts

You can provide the url of a single post or the main url of the Substack you want to download.

By providing the main URL of a Substack, the downloader will download all the posts of the archive.

When downloading the full archive, if the downloader is interrupted, at the next execution it will resume the download of the remaining posts.

Usage:
  sbstck-dl download [flags]

Flags:
      --add-source-url         Add the original post URL at the end of the downloaded file
      --download-files         Download file attachments locally and update content to reference local files
      --download-images        Download images locally and update content to reference local files
  -d, --dry-run                Enable dry run
      --file-extensions string Comma-separated list of file extensions to download (e.g., 'pdf,docx,txt'). If empty, downloads all file types
      --files-dir string       Directory name for downloaded file attachments (default "files")
  -f, --format string          Specify the output format (options: "html", "md", "txt" (default "html")
  -h, --help                   help for download
      --image-quality string   Image quality to download (options: "high", "medium", "low") (default "high")
      --images-dir string      Directory name for downloaded images (default "images")
  -o, --output string          Specify the download directory (default ".")
  -u, --url string             Specify the Substack url

Global Flags:
      --after string    Download posts published after this date (format: YYYY-MM-DD)
      --before string   Download posts published before this date (format: YYYY-MM-DD)
      --cookie_name cookieName   Either substack.sid or connect.sid, based on your cookie (required for private newsletters)
      --cookie_val string        The substack.sid/connect.sid cookie value (required for private newsletters)
  -x, --proxy string    Specify the proxy url
  -r, --rate int        Specify the rate of requests per second (default 2)
  -v, --verbose         Enable verbose output

Adding Source URL

If you use the --add-source-url flag, each downloaded file will have the following line appended to its content:

original content: POST_URL

Where POST_URL is the canonical URL of the downloaded post. For HTML format, this will be wrapped in a small paragraph with a link.

Downloading Images

Use the --download-images flag to download all images from Substack posts locally. This ensures posts remain accessible even if images are deleted from Substack's CDN.

Features:

• Downloads images at optimal quality (high/medium/low)
• Creates organized directory structure: {output}/images/{post-slug}/
• Updates HTML/Markdown content to reference local image paths
• Handles all Substack image formats and CDN patterns
• Graceful error handling for individual image failures

Examples:

# Download posts with high-quality images (default)
sbstck-dl download --url https://example.substack.com --download-images

# Download with medium quality images
sbstck-dl download --url https://example.substack.com --download-images --image-quality medium

# Download with custom images directory name
sbstck-dl download --url https://example.substack.com --download-images --images-dir assets

# Download single post with images in markdown format
sbstck-dl download --url https://example.substack.com/p/post-title --download-images --format md

Image Quality Options:

• high: 1456px width (best quality, larger files)
• medium: 848px width (balanced quality/size)
• low: 424px width (smaller files, mobile-optimized)

Directory Structure:

output/
├── 20231201_120000_post-title.html
└── images/
    └── post-title/
        ├── image1_1456x819.jpeg
        ├── image2_848x636.png
        └── image3_1272x720.webp

Downloading File Attachments

Use the --download-files flag to download all file attachments from Substack posts locally. This ensures posts remain accessible even if files are removed from Substack's servers.

Features:

• Downloads file attachments using CSS selector .file-embed-button.wide
• Optional file extension filtering (e.g., only PDFs and Word documents)
• Creates organized directory structure: {output}/files/{post-slug}/
• Updates HTML content to reference local file paths
• Handles filename sanitization and collision avoidance
• Graceful error handling for individual file download failures

Examples:

# Download posts with all file attachments
sbstck-dl download --url https://example.substack.com --download-files

# Download only specific file types
sbstck-dl download --url https://example.substack.com --download-files --file-extensions "pdf,docx,txt"

# Download with custom files directory name
sbstck-dl download --url https://example.substack.com --download-files --files-dir attachments

# Download single post with both images and file attachments
sbstck-dl download --url https://example.substack.com/p/post-title --download-images --download-files --format md

File Extension Filtering:

• Specify extensions without dots: pdf,docx,txt
• Case insensitive matching
• If no extensions specified, downloads all file types

Directory Structure with Files:

output/
├── 20231201_120000_post-title.html
├── images/
│   └── post-title/
│       ├── image1_1456x819.jpeg
│       └── image2_848x636.png
└── files/
    └── post-title/
        ├── document.pdf
        ├── spreadsheet.xlsx
        └── presentation.pptx

Listing posts

Usage:
  sbstck-dl list [flags]

Flags:
  -h, --help         help for list
  -u, --url string   Specify the Substack url

Global Flags:
      --after string    Download posts published after this date (format: YYYY-MM-DD)
      --before string   Download posts published before this date (format: YYYY-MM-DD)
      --cookie_name cookieName   Either substack.sid or connect.sid, based on your cookie (required for private newsletters)
      --cookie_val string        The substack.sid/connect.sid cookie value (required for private newsletters)
  -x, --proxy string    Specify the proxy url
  -r, --rate int        Specify the rate of requests per second (default 2)
  -v, --verbose         Enable verbose output

Private Newsletters

In order to download the full text of private newsletters you need to provide the cookie name and value of your session. The cookie name is either substack.sid or connect.sid, based on your cookie. To get the cookie value you can use the developer tools of your browser. Once you have the cookie name and value, you can pass them to the downloader using the --cookie_name and --cookie_val flags.

Example

sbstck-dl download --url https://example.substack.com --cookie_name substack.sid --cookie_val COOKIE_VALUE

Thanks

• wemoveon2 and lenzj for the discussion and help implementing the support for private newsletters

TODO

• Improve retry logic
• Implement loading from config file
• Add support for downloading images
• Add tests
• Add CI
• Add documentation
• Add support for private newsletters
• Implement filtering by date
• Implement resuming downloads