If it is based on legitimate interest, under gdpr you don't.

layer8 6 days ago | parent | next [-]

You are required to inform the affected users, however.

Legitimate interest of the user, not yours. Rule of thumb, if its not a legal requirement, you need consent.

That’s not true. From the law as written:

> legitimate interests pursued by the controller or by a third party…

There are six lawful bases for processing, consent is only one of them.

	▲	aforwardslash 6 days ago \| parent [-]
		"legitimate interests" are subject to interpretation on purpose; either legitimate interests on a given instance are lawful, or you're better off relying on consent, since your interpretation and the regulator's interpretation may be different. Check page 7 of https://www.edpb.europa.eu/system/files/2024-10/edpb_guideli...