Can I customize the slashtag on links I create?

Of course, you can set a value for slashtag field when creating a new link.
Mind that you cannot edit a link's slashtag once the link is created.

Are client integrations supposed to save the link ID to be able to get/edit/delete the link afterward?

Not necessarily. By properly using filters of List of links endpoint, you can uniquely fetch a specific link when you know in advance in which workspace it was created, and when you know at least the short URL itself.
Double check example in Getting link details, you can exploit it to build a clean integration which does not need to store anything on your model about Rebrandly IDs.

Is it possible to fetch a link if you only know its destination URL?

No. In Rebrandly you can rebrand a given destination URL many times with many different branded domains and slashtags, this is the reason why you cannot fetch links by destination URL.
If your system is in need to fetch by destination URL (e.g. blog posts sharing), we recommend you to use hashing techniques to choose your slashtag when you create the link: if you can correspond every destination URL to a specific hash code, you can always easily fetch the right link by means of calculating the hash of the destination URL.

Does Rebrandly API support bulk link creation?

No. There is no possibility yet to create/edit or delete links in batch.
There are ways to bulk-import links in Extended Workspaces, available on Enterprise-grade plans.

How to configure different behaviors for slashtag autogeneration?

Unfortunately, there is no API support to interact with slashtag generation.
API clients are supposed to build their own slashtag generation systems to avoid URL collisions and to match their application needs.

Can I integrate Salesforce Marketing Cloud with Rebrandly API to shorten URLs in customer journeys?

Yes, double check our API example in AMPscript in code snippet.
Mind that, in order to parse JSON's result, the example makes use of Server-Side Javascript (SSJS).
Furthermore, if you need assistance for a custom Salesforce to Rebrandly integration, you can contact this Salesforce certified national consulting partner at

Which protocol should I prepend to short links returned by the API?

The Link entity comes with a .shortUrl property which doesn't hardcode any of http:// or https:// protocols. This choice, in v1, was an intentional one, to allow API clients getting more control over the protocol of choice. Eventually, a new option was delivered in the Rebrandly Dashboard - "Copy links with HTTPS (or with HTTP)" which defaults to "Copy links with HTTPS", and can be switched back to "Copy links with HTTP" according to the User preference.
Rebrandly recommends all API clients to start honoring the User's preference for protocol, which can be read in the Link entity in property [link.]domain.sharing.protocol.default and can be any of: http, https. The final short URL, ready to be shared on the web, would then be composed as follows

let link = fetch(``, options) // the Link entity
let shareMe = `${link.domain.sharing.protocol.default}://${link.shortUrl}`