Can I reuse a deleted slug?
Yes - it's freed up immediately, for anyone.
Yes. If you delete a link (or just one of its short URLs), that slug becomes available again right away on that domain - you or anyone else can claim it next.
There's no cooldown period and no way to reserve it for yourself only.
Related articles
Bulk actions - Select multiple links and delete them in one action.
How to change a destination URL - Edit it directly, or schedule a future swap.
How to create a branded short link - Connect your domain first, then pick it when creating a link.
How to create a link - Name, destination, optional branded domain, optional custom slug.