4chan Thread Archiver

Download entire 4chan threads — every image, every video, full quality. Generates a single self-contained HTML viewer with authentic 4chan styling that works completely offline.

Get started:

archive.bat https://boards.4chan.org/g/thread/12345678

Why this tool?

Most 4chan archiver scripts dump files in a folder with zero post context. This tool downloads all media in parallel and generates a single HTML file with authentic Yotsuba B styling, quote hover previews, inline expansion, grid layout, and native video playback — all fully offline.

Features

• Full quality images & videos — downloads original attachments at full quality without compression
• Offline HTML viewer — single file opens in any browser, works completely offline under file:// protocol
• Parallel downloads — concurrent file downloads with configurable limits (defaults to 4, supports 1-16)
• Native video player — WebM and MP4 rendered with HTML5 video player, playback controls, autoplay, loop, and auto-mute
• Expand / collapse images — dedicated toggle to expand or collapse all static image attachments inline
• Drag-to-resize — expanded images and video players can be resized via mouse dragging with aspect ratio preservation
• Quote hover previews — hover over >>quotelinks to see a floating preview of the referenced post
• Dynamic backlinks — auto-generated quote backlinks with scroll-to-highlight navigation
• Authentic Yotsuba B styling — beige post boxes, green tripcodes, greentext, capcodes, post headers
• List / Grid toggle — switch between authentic single-column and responsive card grid layouts
• Idempotent downloads — automatically skips already-downloaded files for fast, efficient updates
• Error resilience — exponential backoff retries, connection timeouts, and dynamic API rate limiting

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Requirements

• Windows with PowerShell 5.1+ (included in Windows 10/11)

Quick Start

Single thread

archive.bat https://boards.4chan.org/g/thread/12345678

Interactive mode (paste multiple URLs)

archive-interactive.bat

Or run the PowerShell script directly:

.\archive-interactive.ps1

PowerShell directly

.\archive.ps1 "https://boards.4chan.org/g/thread/12345678"

List archived threads

list-archives.bat

Refresh UI on all archives

If you update the tool and want existing archives to use the latest HTML/template:

update-html.bat

Or refresh a single archive:

.\update-html.ps1 -ArchiveName "g_12345678"

This regenerates thread.html from the saved thread.json without re-downloading anything. Useful for threads that are no longer available online.

Auto-update all live threads

Fetch fresh data from 4chan for every archive, download new posts/images, and regenerate HTML:

update-all.bat

• Threads that are still alive get new posts downloaded
• Threads that have been removed (404) are marked as REMOVED but their local files are preserved
• Threads with no changes are skipped
• Rate limited to respect 4chan API rules

Supported URL formats

All of these work:

https://boards.4chan.org/g/thread/12345678
https://boards.4channel.org/a/thread/12345678
https://4chan.org/g/thread/12345678
https://a.4cdn.org/g/thread/12345678.json

Options

Parameter	Default	Description
Url	(required)	Thread URL to archive
-Concurrency	4	Number of parallel downloads (1-16)
-DelayMs	0	Delay between file downloads in milliseconds (0-10000) to prevent rate limiting

Example with custom parallelism and rate-limiting delay:

.\archive.ps1 "https://boards.4chan.org/g/thread/12345678" -Concurrency 4 -DelayMs 250

Output structure

archives/
  g_12345678_mechanical_keyboards/
    thread.html          <- open this in a browser
    thread.json          <- cached API response for efficient updates
    images/
      1234567890123.jpg  <- full quality image
      1234567890123s.jpg <- thumbnail
      ...

The thread.html file is fully self-contained. It references images from the local images/ folder, so it works completely offline with no internet connection needed.

Updating archives

If a thread is already archived, the tool will ask whether to update:

Thread already archived at: archives/g_12345678
Update with new posts? (Y/n)

Press Enter (or y) to fetch new posts. Only images from new posts are downloaded -- existing images are never re-downloaded. The HTML is regenerated with all posts.

The cached thread.json is used to detect which posts are new, making updates fast even for large threads.

Notes

• Respects 4chan API rate limits via parallel connection cap
• Deleted threads or 404s will show an error and clean up the folder (new archives only; existing archives are preserved on update failure)
• Thumbnails are downloaded alongside full images for fast browsing