Strongly not recommended to expose entity ids externally (especially in a durable way).

There are various reasons in the evolution of your database which may cause you to renumber your entities, so don't rely on entity ids being stable.

Thanks v much for the help. So, If I'm going to create e.g. :user/id, is there any support for generating those IDs?

You could use UUIDs, or if that's not suitable use or take inspiration from https://github.com/vvvvalvalval/datofu#generating-unique-readable-ids

UUID seems like overkill for something that only needs to be unique within this database

Overkill in what sense? UUIDs are essentially the least thought-consuming id generation strategy, it's the last thing I'd call overkill 🙂

I guess I meant unnecessarily large, but I take your point.

Oh I see. Well, 128 bits of entropy, could be worse. I think Datomic has efficient storage and memory layouts for it. You could also represent it in text by encoding it in base64, this way you can represent it with 22-chars Strings, not that bad.

https://github.com/tonsky/compact-uuids @U0GQG7ZV5

You can find much shorter for not-quite-uuids

@U09K620SG thanks for the pointer. However: > Many UUID generators produce data that is particularly difficult to index, which can cause performance issues creating indexes. To address this, Datomic includes a semi-sequential UUID generator (https://docs.datomic.com/on-prem/identity.html) I think I'll just accept the long URLs 🙂

Is squuid still a thing? I thought Datomic has since solved this with adaptive indexing

Hmm that could well be true. I have no idea

https://forum.datomic.com/t/why-no-d-squuid-in-datomic-client-api/446

Found something similar at the same time. Thanks