Digital congruence in influencer marketing: how NFTs shift the balance between human and AI-driven virtual endorsers through parasocial relationships

Purpose This study investigates how endorser type (AI-driven virtual vs. human influencers) interacts with product type (NFT vs. physical goods) to shape brand engagement through parasocial relationships. It introduces the concept of digital congruence, examining when fully digital influencers are more effective than their human counterparts in the context of digitally native products. Design/methodology/approach Across three online experiments (Study 1: N = 403; Study 2: N = 663; Study 3: N = 359), this research tests a moderated mediation framework. Study 1 examines the mediating role of parasocial relationships in the influencer–engagement link. Studies 2 and 3 introduce NFT presence as a moderator to evaluate how digital congruence alters consumer response across cultures (UK and China). Findings Human influencers generally elicit stronger parasocial relationships and brand engagement when promoting physical products. However, virtual influencers outperform human endorsers in NFT contexts, driven by enhanced digital congruence. Parasocial relationships mediate the influence of endorser type on engagement, and this mediation is moderated by the presence of NFTs. Practical implications Marketers should align influencer type with product ontology. For traditional goods, human influencers are preferable; for NFTs and other digital assets, virtual influencers yield superior engagement outcomes. Digital congruence enhances parasocial bonds and should be strategically leveraged in Web3 campaigns. Originality/value This research bridges congruence theory and parasocial relationship theory to propose digital congruence as a novel construct. It is the first to empirically demonstrate that alignment between a fully digital endorser and a fully digital product (NFT) enhances psychological resonance and marketing effectiveness.