How to Cross-Post on Reddit Without Repost Detection
Reddit's repost detection is unlike any other platform because it is largely community-driven through automated bots rather than platform-level enforcement. Bots like RepostSleuthBot use perceptual hashing to identify duplicate images and videos across subreddits. ShadowReel's pixel modifications defeat these hash comparisons while preserving full visual quality.
How Does Reddit Detect Reposts?
Reddit relies on three separate detection layers. The first and most common is RepostSleuthBot, which operates in over 3,500 subreddits and has scanned more than 400 million posts. It uses difference hashing (dHash) and average hashing (aHash) to generate 64-bit perceptual fingerprints of images. When a new post's hash falls within a Hamming distance of 8 bits from an existing post, it is flagged as a repost.
- RepostSleuthBot: Community bot using perceptual hashing (dHash/aHash), active in 3,500+ subreddits
- Reddit's native detection: Basic duplicate URL matching and identical image hash detection on popular subreddits
- Moderator tools: Many large subreddits use AutoModerator rules that check post similarity using third-party APIs
How Accurate Is RepostSleuthBot?
RepostSleuthBot reports a self-claimed accuracy of 97% for images and 89% for videos. However, it has well-known weaknesses that ShadowReel exploits:
| Modification Type | Defeats RepostSleuthBot? | Visible to Viewer? |
|---|---|---|
| Basic crop (5-10%) | Sometimes (~60%) | Yes, noticeable |
| Add border/watermark | Sometimes (~70%) | Yes, very noticeable |
| Color filter/overlay | Rarely (~40%) | Yes, degrades quality |
| Mirror/flip | Yes (~95%) | Yes, text appears reversed |
| ShadowReel Standard | Yes (~99%) | No, imperceptible |
| ShadowReel Enhanced | Yes (~99.5%) | No, imperceptible |
Perceptual hashing algorithms compare overall image structure. ShadowReel modifies sub-pixel color values and applies micro-noise patterns that shift the hash by 15-25 bits, well beyond the 8-bit matching threshold.
What Are the Best ShadowReel Settings for Reddit?
| Setting | Value |
|---|---|
| Preset | reddit |
| Resolution | Native (preserves original) |
| Video Bitrate | 8 Mbps |
| Audio Bitrate | 192 kbps |
| Max Duration | 120 seconds |
| Image Quality | 97 (JPEG) |
| Recommended Stealth | Standard (sufficient) |
The Reddit preset preserves native resolution because Reddit does not enforce specific aspect ratios. Unlike Instagram or TikTok, Reddit displays content at its original dimensions, so rescaling would be unnecessary quality loss.
How Should You Cross-Post Across Multiple Subreddits?
Cross-posting the same content across multiple subreddits is where ShadowReel provides the most value on Reddit. The recommended workflow is:
- Process your original image or video through ShadowReel once per target subreddit
- Each processed copy receives a unique fingerprint, so no two posts will match each other
- Space your posts at least 15-30 minutes apart to avoid Reddit's spam velocity filters
- Use different titles for each subreddit to avoid AutoModerator cross-post detection rules
Caveat: Reddit's spam filters also analyze account behavior. New accounts (under 30 days or below 100 karma) face stricter automated scrutiny. Processing content through ShadowReel addresses the media detection layer, but account-level trust must be built independently.
Does ShadowReel Work for Reddit Image Posts?
Yes. ShadowReel processes both images and videos. For Reddit image posts, the tool applies Float64 pixel-level modifications that shift color values by 0.1-0.4% per channel. This generates a completely different perceptual hash while maintaining visual quality at JPEG quality 97, which is indistinguishable from the original at Reddit's display resolution. PNG sources are converted to high-quality JPEG to match Reddit's internal processing pipeline.