Posts in Mastodon can be set to automatically self-destruct after a certain time period, with exceptions made for posts you want to keep. Here’s how to do it:
- Log in through your server’s website or the web app
- Go to Preferences > Automated post deletion (on mobile web click ⚙️, then ☰, then Automated post deletion)
- Tick the box at the top marked Automatically delete old posts
- Choose the Age threshold to set how long posts are around before they’re deleted. This can be from 1 week to 2 years.
- Set the exceptions for posts you want to keep, in the section marked Exceptions and also in the section marked Exceptions based on interactions
- Click the Save changes button ( ⚠️ Only click this button if you are sure you want to activate autodelete and if you are 100% happy with your settings!)
What if I want to keep some old posts and autodelete the rest?
The autodelete options let you choose many types of exceptions that don’t ever get deleted, for example pinned posts, DMs, polls, image posts etc.
If you want to keep specific posts that don’t fit into a neat category, bookmark your posts that you want to keep before setting up autodelete, and then during autodelete setup choose the option to keep bookmarked posts before you click “Save changes”.
What if I want to keep my most popular posts?
There’s an option in the autodelete setup which lets you keep posts that have more than a certain number of boosts or favourites, it’s in the section marked Exceptions based on interactions.
What if I don’t want autodeletion at all?
Autodelete is off by default. If you never activate it, it will not do anything.
What if I change my mind? How do I stop posts being deleted automatically?
If you activate autodelete but then change your mind and want to stop deleting posts automatically, UN-tick the box marked Automatically delete old posts, and click the Save changes button.
⚠️ Will stopping the auto-deletion bring back posts that are already deleted?
No. Once a post is deleted it is gone. Be sure you want to use auto-deletion before you activate it.
What happens to discussions based on my posts?
If you delete a post that other people replied to, the replies to your post will be orphaned, and it will become impossible to discover or browse such discussions. If you want to keep certain discussions you’ve started in existence, make sure you include your posts from that discussion in the list of exceptions (see Step 5 in the instructions at the top of the page).
What happens to links to my posts?
If you delete a post, any links to that post will immediately be broken and will just show an error message. If you want to keep a post, make sure it is covered by the exceptions list in Step 4 of the instructions.
I activated auto-deletion but it hasn’t deleted posts that are way past the threshold. What’s going on?
If servers are busy, they create queues of tasks to work through. Automated deletion tends to go at the back of the queue, so it may take longer to happen than other tasks. If the settings are correct and it’s way past the deadline for the deletions to happen, ask your server’s admin for advice.
How does this affect server running costs?
When this feature is discussed, the issue of server running costs is often raised:
- On the one hand, automated stuff always adds extra tasks for the server to carry out. Servers are only capable of doing a certain amount of tasks at once, and expanding this capability costs money.
- On the other hand, deleting posts (and especially attachments like images or videos) would mean the server doesn’t have to store as much data, which saves money on storage costs. It would also reduce storage costs for any servers that have federated the posts being deleted.
You would have to speak to your server’s admin to find out exactly how it affects their setup, as different servers may have different resources available.
I asked a couple of very large server admins for their thoughts on how this balances out. Both of them said the added tasks were insignificant compared to everything else the servers have to do. Both of them also said deleting posts (especially posts with media attachments) saves storage, but one of them added that there may be fees to be paid if the deletions happen for very recent posts. On their server, it would be cheaper to only delete posts more than 90 days old, and leave any newer posts intact.