Mastodon Upload Guide

Post text, photos and videos to Mastodon — on any instance — using the IndReelForge API. Mastodon connects with your instance URL and an access token from an application you create on that instance.

Supported Content Types

Type	Endpoint	Notes
Text post	POST /api/upload_text	Up to 500 characters (the default instance limit)
Photos	POST /api/upload_photos	Up to 4 photos per post
Video	POST /api/upload	1 video per post, max 40 MB

Limits

Limit	Value
Post length	500 characters
Photos per post	4
Videos per post	1 (photos and a video can't be mixed)
Max file size	40 MB
Posting rate	Default instance limit: 300 posts per 3 hours

Some instances set different limits; the values above are Mastodon's defaults.

Get an Access Token

1. Sign in to your Mastodon instance in a browser (e.g. https://mastodon.social).
2. Open Preferences → Development → New application.
3. Enter an application name (e.g. IndReelForge).
4. Under Scopes, make sure write:statuses and write:media are ticked. You can untick the others.
5. Click Submit, open the application you just created and copy Your access token.

Connect Mastodon

From the dashboard

1. Dashboard → Profiles → select your profile
2. Click Connect next to Mastodon
3. Enter the Instance URL (e.g. https://mastodon.social) and the Access token
4. IndReelForge verifies the token with your instance before saving — status shows Connected

With the API

curl -X POST https://api.indreelforge.com/api/profiles/my-brand/connect/mastodon/credentials \
  -H 'Authorization: Apikey YOUR_KEY' \
  -H 'Content-Type: application/json' \
  -d '{"instance_url": "https://mastodon.social", "access_token": "YOUR_MASTODON_TOKEN"}'

Field	Required	Description
instance_url	Yes	The address of your Mastodon server
access_token	Yes	Access token with write:statuses and write:media

See Connect with Credentials for the full request and response format.

Post a Text Update

curl -X POST https://api.indreelforge.com/api/upload_text \
  -H 'Authorization: Apikey YOUR_KEY' \
  -F 'user=my-brand' \
  -F 'title=Hello fediverse! We are now posting here too. #introduction' \
  -F 'platform[]=mastodon'

Post Photos

curl -X POST https://api.indreelforge.com/api/upload_photos \
  -H 'Authorization: Apikey YOUR_KEY' \
  -F 'user=my-brand' \
  -F 'title=Sunset from the office roof' \
  -F 'photos[]=@/path/to/photo1.jpg' \
  -F 'photos[]=@/path/to/photo2.jpg' \
  -F 'platform[]=mastodon'

Post a Video

curl -X POST https://api.indreelforge.com/api/upload \
  -H 'Authorization: Apikey YOUR_KEY' \
  -F 'user=my-brand' \
  -F 'title=60-second product tour' \
  -F 'video=@/path/to/video.mp4' \
  -F 'platform[]=mastodon'

Post Across Mastodon + Bluesky + Threads

curl -X POST https://api.indreelforge.com/api/upload_text \
  -H 'Authorization: Apikey YOUR_KEY' \
  -F 'user=my-brand' \
  -F 'title=Our new release is out — what should we build next?' \
  -F 'platform[]=mastodon' \
  -F 'platform[]=bluesky' \
  -F 'platform[]=threads'

Use mastodon_title to send Mastodon different text than the other platforms in the same request.

Troubleshooting

Problem	Cause	Fix
Connect fails with INVALID_CREDENTIALS	Wrong instance URL or token, or the token was revoked	Check the instance address and copy the token again
Media upload rejected	The token lacks write:media	Edit the application, tick write:media, and reconnect with the token
Post rejected as too long	Over the instance's character limit (500 by default)	Shorten the text or use mastodon_title
More than 4 photos	Mastodon allows 4 attachments per post	Send up to 4 photos
Rate limited	Instance limit reached (300 posts / 3 hours by default)	Space posts out or schedule them