Automatically Post Reddit to TikTok: Complete Guide
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Reddit reaches Young adults interested in niche communities while TikTok connects with Gen Z and young Millennials, letting you expand to a new audience segment. Your Reddit content format works on TikTok, so you can share without creating entirely new content. Whether you want to auto-post everything or filter by hashtag, this guide covers everything about Reddit to TikTok automation. Learn how to crosspost from Reddit to TikTok or repurpose your content for maximum reach.
Reddit to TikTok Content Compatibility
Video
Needs Adaptation
Images
Needs Adaptation
Text/Captions
Truncated
Reddit vs TikTok: Platform Specs
| Spec | TikTok | |
|---|---|---|
| Caption Limit | 40,000 chars | 4,000 chars |
| Max Video Length | 15min | 10min |
| Preferred Aspect Ratio | 16:9 | 9:16 |
| Max Video File Size | 1GB | 4GB |
| Carousel Support | Up to 20 items | Up to 35 items |
| Hashtag Strategy | Not used | Unlimited |
| Link Support | Yes | No |
| Primary Audience | 18-39 | 16-34 |
Why Automate Reddit to TikTok?
Clip highlights from long-form Reddit content into short TikTok posts
Build a consistent brand presence across Reddit and TikTok with automated distribution
Grow your TikTok following by consistently sharing your best Reddit content
Manual Posting vs Automated Distribution
Manual Method
- ✗Upload the same video to TikTok after posting to Reddit
- ✗Copy and reformat captions for each platform
- ✗Constantly context-switch between apps
- ✗Risk forgetting to post to TikTok
- ✗Spend 10-15 minutes per post managing distribution
- ✗Miss peak posting times on TikTok
PostOnce Automation
- ✓Post to Reddit like normal—we handle TikTok
- ✓Captions automatically adapted for TikTok
- ✓Stay in your favorite platform's workflow
- ✓Every Reddit post automatically appears on TikTok
- ✓Set up once in under 60 seconds
- ✓Consistent posting schedule maintained automatically
Manual posting might work when you're just starting out, but as your content volume grows, automation becomes essential. The difference isn't just time saved—it's the ability to maintain a consistent multi-platform presence without burning out.
How to Set Up Reddit to TikTok Automation
Connect Reddit and TikTok
Link both social accounts to PostOnce using secure OAuth authorization.
Reddit uses standard OAuth and TikTok requires platform-specific authorization. Both connect in seconds.
Configure your automation rules
Choose to crosspost everything or filter by hashtags, content type, or custom rules.
Since Reddit allows longer captions (40,000 chars) than TikTok (4,000 chars), you may want to review caption truncation settings.
Post on Reddit as usual
Create content on Reddit and PostOnce handles TikTok distribution.
Your 16:9 Reddit content is automatically reformatted to 9:16 for TikTok.
Flexible Automation Options
Control exactly how your Reddit content gets distributed to TikTok with powerful automation rules.
Post Everything
Every Reddit post automatically goes to TikTok
Filter by Hashtag
Use specific hashtags to control what gets crossposted to TikTok
Custom Rules
Set advanced filters based on your Reddit to TikTok workflow needs
Most creators use hashtag filtering to maintain control over their crossposting workflow. For instance, you might want all your Reddit tutorials to go to TikTok, but keep personal content separate. Simply add a specific hashtag like #autopost to your Reddit caption, and only those posts will be distributed.
If you want to repurpose content from Reddit to TikTok, you can also customize how captions, formats, and media are adapted for each platform's unique audience and requirements.
What to Expect
Works Well
- ✓Photos and images work well on both platforms
Needs Adaptation
- ~Video aspect ratio needs to change from 16:9 to 9:16
- ~Captions may need shortening (40,000 chars to 4,000 chars)
- ~Videos over 10 minutes need trimming for TikTok
- ~Hashtag strategy differs between Reddit and TikTok
Doesn't Transfer
- ✗Polls cannot be recreated on TikTok
- ✗Clickable links in captions are not supported on TikTok
Known Limitations
- ⚠Reddit videos longer than 10 minutes need to be trimmed for TikTok
- ⚠Captions over 4,000 characters will be shortened for TikTok
Frequently Asked Questions
TikTok supports videos up to 10 minutes long, 4GB file size, in 9:16, 1:1 aspect ratios. Captions can be up to 4,000 characters. Since Reddit allows up to 15 minutes, longer videos will need trimming.
Yes. PostOnce works with both personal and business accounts on both Reddit and TikTok. Connect via OAuth authorization—your credentials are never stored.
Reddit's peak engagement is 6-8 AM, 12-2 PM (US timezones), while TikTok's peak is 7-9 AM, 12-3 PM, 7-11 PM. PostOnce can publish to TikTok at optimal times regardless of when you post on Reddit.
Hashtags are not used on Reddit. For TikTok: Hashtags boost discoverability via For You Page algorithm. PostOnce lets you customize hashtag handling—keep them, remove them, or set platform-specific hashtag strategies.
PostOnce handles unlimited crossposting within your plan's limits. Every time you post on Reddit, it's automatically shared to TikTok—no per-post limits on automation.
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