> ## Documentation Index
> Fetch the complete documentation index at: https://postmesh.app/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Pre-flight checks before every post

> What PostMesh checks before it sends a post: caption length, hashtags, file type and size, video length, aspect ratio, TikTok settings and Reddit rules.

Every post is checked against each network's rules before it goes out.

> [!NOTE]
>
> **In short:** Before sending, PostMesh checks each network's caption limit, media type, size, length and shape, and the settings a network requires. Errors block the post until fixed; warnings don't.

## What's checked

* Caption length, counted the way each network counts it, plus hashtag and mention limits
* File type, file size, dimensions and aspect ratio
* Video length and frame rate
* Media the network requires: Instagram and TikTok need a photo or video, YouTube needs a video and a title
* TikTok: who can watch, and branded content settings
* Reddit: a community's required flair and the post types it allows
* The time you picked, which must be within 12 months

Photos are converted for each network: the right format, resized, and padded with a soft border when the shape is out of range.

## Common messages

| Message | What to do |
| - | - |
| Reel allows up to 2200 characters (2301 used). | That network's caption is too long for its post type. Shorten it, or give that network [its own caption](https://postmesh.app/docs/captions-per-network.md). When scheduling, the message starts with the network's name. |
| Instagram requires media | Add a photo or video, or leave Instagram out of this post. |
| Choose who can see this TikTok post | Pick a privacy option in the TikTok settings. |
| Branded content cannot be Only you | Choose another privacy option for branded content. |
| Publishing currently supports one attachment per post | Keep one file; save the others as separate drafts. |
| An attached file is no longer in storage. Attach it again. | Remove the file and attach it again. |


## Related topics

- [Quickstart: your first post to every network](https://postmesh.app/docs/quickstart.md)
- [AI Agent: draft posts for every network](https://postmesh.app/docs/ai-agent.md)
- [PostMesh docs](https://postmesh.app/docs/index.md)
- [Send a post to your client for approval](https://postmesh.app/docs/client-approvals.md)
- [Post to social media from Claude, Cursor and Codex (MCP)](https://postmesh.app/docs/mcp-setup.md)


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