Threads, Bluesky, and Mastodon channel guide

Publish across open-conversation networks while respecting connection, media, thread, and instance limits.

Threads, Bluesky, and Mastodon look similar in a composer but use different identity and publishing models. Customize each destination instead of assuming one post shape will behave identically everywhere.

Before you start

Keep the shared version within the shortest relevant limit, then customize it per network.
Prepare public media URLs and image alt text.
For Bluesky, create a dedicated App Password; do not use or share the account password.
For Mastodon, confirm which instance this BlendDuck deployment is configured to use.

Connect the accounts

Network	Connection	Publish access
Threads	OAuth	Approve basic profile and content publishing; reconnect with Insights access for Analytics.
Bluesky	Handle and App Password	Enter the full handle and a dedicated App Password.
Mastodon	OAuth	Authorize the account on the deployment's configured HTTPS instance.

Open Dashboard → Channels, connect one network at a time, and verify the returned username before testing. If a Bluesky App Password is ever exposed, revoke it in Bluesky and connect again with a new one.

Match the format

Network	Text	Media and threads
Threads	Up to 500 characters	Text only or one public HTTPS image/video; BlendDuck does not publish a reply chain.
Bluesky	Up to 300 graphemes	Up to four images, 2 MB each; reply chains are supported. Video is not supported.
Mastodon	Up to 500 characters in the current adapter	Images/videos with alt text; reply chains are supported. Native instance limits can vary.

For a reply chain, read the full sequence in preview. BlendDuck publishes it in order, so a failure in a later reply can leave the earlier portion live. Threads media can remain processing while its container is prepared; wait for the status result instead of submitting a duplicate.

Use Analytics

All three connections can report posts and follower history. Threads data can lag about 24 hours and refreshes daily. Bluesky and Mastodon have no configured delay and refresh about hourly, although the providers may still return partial data. None of these connections provides Social Inbox actions.

You are done when

each connected username and Mastodon instance is correct;
a test post opens on every intended network with the expected media and alt text; and
reply chains, processing states, and reporting delay match the plan.

If something blocks you

Symptom	Next action
Threads media stays processing	Wait for the provider status; read the failure reason before retrying.
Threads Analytics is empty	Allow about 24 hours and reconnect if Insights access was omitted.
Bluesky sign-in fails	Use the full handle and a current App Password, never the main password.
Bluesky image is rejected	Use at most four images, each no larger than 2 MB.
Mastodon authorization opens the wrong host	Confirm the deployment's configured instance before connecting.
Mastodon rejects content that passed the composer	Follow that instance's native character and media limits.
A reply chain is partial	Inspect which item failed before deciding whether to remove or republish the live prefix.

See Channel capabilities before promising Inbox or reporting behavior across networks.