PostEverywhere Media Requirements Reference
Image dimensions, video duration limits, file sizes, aspect ratios, and format requirements for every platform supported by the PostEverywhere API.
Each social platform enforces its own limits on file sizes, dimensions, video duration, and formats. This page covers every constraint so you can validate media before uploading.
Upload limits that apply to every platform
The PostEverywhere API accepts files up to these sizes:
| Type | Maximum Size |
|---|---|
| Images | 20 MB |
| Videos | 4 GB |
| PDFs | 20 MB |
Accepted image and video MIME types
image/jpeg
image/png
image/gif
image/webp
image/heic
image/heif
video/mp4
application/pdf
Only video/mp4 is accepted for video uploads. If your source video is in another format, transcode it to H.264 MP4 before uploading.
Files in Google Drive: in the PostEverywhere web app, New Post and Media have an Add from Google Drive button that copies the photos and videos you pick into your media library. The API and MCP server do not fetch from Drive, and Drive share links are not accepted as media URLs.
Maximum file size, platform by platform
The API enforces the PostEverywhere upload limits above, but individual platforms may reject media that exceeds their own limits. Ensure your files stay within these bounds:
| Platform | Image Max | Video Max | Other |
|---|---|---|---|
| 30 MB | 500 MB | -- | |
| X / Twitter | 5 MB | 512 MB | -- |
| 100 MB | 5 GB | 100 MB (PDF) | |
| 30 MB | 10 GB | -- | |
| TikTok | 20 MB | 4 GB | -- |
| YouTube | -- | 256 GB | -- |
| Threads | 30 MB | 250 MB | -- |
| 100 MB | 2 GB | -- | |
| Telegram | 10 MB | 50 MB | -- |
| Bluesky | 50 MB (recompressed to 2 MB per image) | 100 MB | -- |
| Discord | 25 MB | 25 MB (linked by URL) | -- |
| WordPress | 50 MB | Your site's upload limit (4 GB on our side) | -- |
Tip: PostEverywhere accepts videos up to 4 GB. Each platform's own limit still applies when you post to it (for example X 512 MB, Instagram 500 MB, Bluesky 100 MB).
Minimum and maximum image dimensions
| Platform | Minimum | Maximum / Recommended |
|---|---|---|
| 320 x 320 | 1080 x 1350 (4:5 portrait recommended) | |
| X / Twitter | 600 x 335 | 4096 x 4096 |
| 200 x 200 | 7680 x 4320 | |
| 600 x 315 | 8192 x 8192 | |
| TikTok | 360 x 360 | 1080 x 1920 |
| Threads | 320 x 320 | 1080 x 1350 |
| 200 x 300 | 1000 x 1500 (2:3 recommended) |
Oversized images are resized for you
You do not need to pre-resize images to fit the table above. Media is served to each platform through Cloudflare Images, and where a platform enforces a hard ceiling we request a scaled-down variant automatically, since TikTok's Photo API rejects anything over 1080 px, so a 4032 x 3024 phone photo is delivered to TikTok at 1080 x 810 with the aspect ratio preserved. Images already within a platform's limits are passed through untouched at full resolution.
Maximum video length, platform by platform
| Platform | Minimum | Maximum |
|---|---|---|
| Instagram Reels | 3 seconds | 15 minutes |
| X / Twitter | 0.5 seconds | 2 min 20 sec |
| 3 seconds | 10 minutes | |
| 1 second | 4 hours | |
| TikTok | 3 seconds | 10 minutes |
| YouTube | 1 second | 12 hours |
| Threads | 1 second | 5 minutes |
| 4 seconds | 15 minutes | |
| Bluesky | -- | 3 minutes |
Accepted aspect ratios per platform
Aspect ratio requirements vary significantly by platform. Getting these wrong is one of the most common causes of publishing failures.
| Platform | Accepted Ratios | Notes |
|---|---|---|
| TikTok | 9:16 only | Vertical video is mandatory. Other ratios are rejected. |
| 4:5 to 1.91:1 | 4:5 portrait performs best. Square (1:1) is safe. | |
| X / Twitter | 1:2.39 to 2.39:1 | Wide range accepted. 16:9 is standard. |
| X Article cover | 5:2 recommended | The first image on an X Article becomes its cover. 2000 x 800 pixels looks best. Video is not allowed in an article. |
| 1:2.4 to 2.4:1 | 1:1 or 16:9 recommended for feed. | |
| 9:16 to 16:9 | 4:5 recommended for feed. | |
| YouTube | 16:9 | Other ratios are letterboxed or pillarboxed. |
| Threads | 1:1, 4:5 or 9:16 | Square and portrait only; no landscape. |
| 9:16, 2:3, 4:5 or 1:1 | 2:3 vertical pins perform best. |
TikTok requires 9:16
TikTok strictly rejects any video that is not in 9:16 portrait orientation. Always verify the aspect ratio before publishing to TikTok.
How many images or videos each post allows
Maximum number of media attachments per post:
| Platform | Images | Videos | |
|---|---|---|---|
| 10 (carousel) | 1 (Reels) | -- | |
| X / Twitter | 4 | 1 | -- |
| 20 | 1 | 1 | |
| 10 | 1 | -- | |
| TikTok | 35 (photo carousel) | 1 | -- |
| YouTube | -- | 1 | -- |
| Threads | 10 | 1 | -- |
| 5 (carousel) | 1 | -- | |
| Telegram | 10 | 1 | -- |
| Bluesky | 4 | 1 | -- |
| Discord | 10 (embeds) | 1 (linked by URL) | -- |
| WordPress | 20 (inline or appended) | 1 (top of post) | -- |
Note: You cannot mix images and videos in the same post on most platforms. Instagram carousels are image-only.
Required video codecs and bitrates
PostEverywhere accepts MP4 only, and H.264 is accepted everywhere (some platforms also take H.265 or VP9). Details vary:
| Platform | Codec | Frame Rate | Bitrate |
|---|---|---|---|
| H.264 / H.265 | 23-60 fps | 6-8 Mbps recommended | |
| X / Twitter | H.264 | up to 40 fps | 25 Mbps max |
| H.264 | 10-60 fps | 8 Mbps recommended, 10 Mbps max | |
| H.264 | up to 30 fps | 8 Mbps recommended | |
| TikTok | H.264 / H.265 | 23-60 fps | 6-12 Mbps recommended |
| YouTube | H.264 / H.265 / VP9 | up to 60 fps | 12 Mbps recommended at 1080p |
| Threads | H.264 | 30 fps | -- |
| H.264 / H.265 | up to 60 fps | -- |
Audio should be AAC, 128 kbps or higher. PostEverywhere does not transcode uploaded videos (it verifies the file and extracts a thumbnail), so upload a compliant MP4.
Uploading media, step by step
Two options depending on whether the file is already on the public web:
Option A: Already on a public URL (one call)
If your image is already hosted somewhere publicly fetchable, use POST /v1/media/upload-from-url:
curl -X POST https://app.posteverywhere.ai/api/v1/media/upload-from-url \
-H "Authorization: Bearer pe_live_abc123..." \
-H "Content-Type: application/json" \
-d '{ "url": "https://example.com/hero.webp" }'Response is ready-to-use immediately (media_status: "ready"):
{
"data": {
"media_id": "a1b2c3d4-...",
"media_ids": ["a1b2c3d4-..."],
"media_status": "ready",
"type": "image",
"url": "https://imagedelivery.net/.../img_.../public",
"content_type": "image/webp",
"size": 14914
}
}Images (25 MB cap) import instantly; MP4 videos (4 GB cap) import asynchronously: poll GET /v1/media/{id} until media_status is ready. For local files, use Option B.
Option B: Local file (3-step flow)
For local files, the upload is a 3-step process: request a presigned URL, upload bytes to it, then finalise. Through the MCP server the same flow is the create_media_upload and complete_media_upload tools, which also take a PDF for a LinkedIn document post.
Step 1: Request a presigned upload URL
POST /v1/media/upload takes JSON describing the file you're about to upload, not the file itself. Field names are filename, content_type, size (not file_name, mime_type, file_size).
curl -X POST https://app.posteverywhere.ai/api/v1/media/upload \
-H "Authorization: Bearer pe_live_abc123..." \
-H "Content-Type: application/json" \
-d '{
"filename": "photo.jpg",
"content_type": "image/jpeg",
"size": 2048000
}'The response includes a media_id, an upload_url, and an upload_method describing how to upload:
{
"data": {
"media_id": "a1b2c3d4-...",
"upload_url": "https://upload.imagedelivery.net/...",
"upload_method": {
"method": "POST",
"content_type": "multipart/form-data",
"field_name": "file"
},
"media_status": "uploading"
}
}Step 2: Upload the bytes to upload_url
Image upload URLs are not S3-style
Sending
PUTwith raw bytes to an imageupload_urlreturns400 {"code":100,"message":"method is not supported"}. Image URLs are Cloudflare direct-upload endpoints: usePOSTwithmultipart/form-dataand the file in the field named byupload_method.field_name(usuallyfile). Only video and PDF URLs acceptPUTwith raw bytes.
For images, send a multipart POST with the field name from upload_method.field_name (usually file):
curl -X POST "<upload_url>" \
-F "file=@photo.jpg"For videos, use the PUT method with the correct Content-Type header (upload_method.method will be PUT and upload_method.headers tells you the header to send).
Step 3: Finalise
This step is required: without it the media stays in media_status: "uploading" and POST /v1/posts will reject attempts to attach it.
curl -X POST https://app.posteverywhere.ai/api/v1/media/{media_id}/complete \
-H "Authorization: Bearer pe_live_abc123..."After Step 3 the media is ready and you can attach it via media_ids in a post.
Polling for video processing (Option B videos only)
Videos go through additional processing for thumbnail extraction. After Step 3 returns ready, the file is uploadable but the thumbnail may still be generating. Poll GET /v1/media/{id} if you need the thumbnail_url field populated.
Step 4: Attach to a post
curl -X POST https://app.posteverywhere.ai/api/v1/posts \
-H "Authorization: Bearer pe_live_abc123..." \
-H "Content-Type: application/json" \
-d '{
"content": "Check out this photo!",
"account_ids": [123],
"media_ids": ["550e8400-e29b-41d4-a716-446655440000"],
"scheduled_for": "2026-04-15T10:00:00Z"
}'Always confirm the media status is ready before attaching it to a post. See Upload Media for the full endpoint reference.
Related media and platform pages
- Upload Media -- upload endpoint reference
- Schedule a Post -- attach media to posts
- Error Handling -- media-related error codes (
unsupported_media_type,file_too_large,file_type_mismatch)
Related: Instagram API guide · TikTok API guide · YouTube API guide · testing uploads safely · storage included in each plan