If you want to schedule messages with Mastodon or Pleroma, you can use

plan.fedilab.app/

It's an open-source web app that doesn't store anything (no database involved).

Source code: github.com/stom79/FediPlan

Follow

More:

This scheduler embeds many features, like autocomplete for tags, mentions and custom emojis. You also have an emoji picker and you can create polls.
Last one important feature, you can edit your media.
You also have an entry that lists all your scheduled messages (you can remove them).

You can host it on your own server otherwise it's here plan.fedilab.app

Sign in to participate in the conversation
Fedilab

A friendly instance about tech, apps and for having fun.