§ 19 of Marknadsföringslagen allows marketing to a natural person by email, fax or automatic calling systems only with consent given in advance. The act defines elektronisk post broadly, as an individualised electronic message in text, voice, sound or image, so the cautious reading treats a WhatsApp offer the same way.
§ 20 adds that marketing email must always carry a valid address where the recipient can ask for it to stop, including when the recipient is a company. On WhatsApp the practical equivalent is a STOP reply that works, which is what InfiQ's consent records enforce.