Significance Most US adults use smartphones for internet access. Understanding what they see when they view smartphone-optimised (mobile) tobacco websites is important, as it can inform tobacco education and cessation strategies. This study describes mobile tobacco websites for leading brands of cigarettes, cigars, smokeless tobacco (smokeless), e-cigarettes and hookah.

Methods We identified 130 leading tobacco brands based on sales, advertising spending and self-report data. Of these, 62 brands had mobile websites. We conducted an inductive content analysis (ie, where we derived the coding scheme from what we observed) of website characteristics by dual-coding: age requirements, warning display, brand engagement methods (eg, social features) and sales strategies (eg, coupons).

Results All cigarette and most smokeless websites required age-verified accounts for entry, while 76% of e-cigarette websites required accounts only for making purchases. All cigarette and smokeless websites showed warnings, but a minority of e-cigarette and cigar websites did, and no hookah websites did. Many websites required users to scroll up to view warnings. Most e-cigarette websites, most hookah websites, and half of cigar websites linked to multiple social media platforms; however, most cigarette and smokeless websites facilitated socialisation internally. All cigarette, most smokeless and no hookah websites offered coupons. Many cigarette and smokeless coupons were time-sensitive and location-based.

Conclusions We highlight issues in how tobacco brand websites address youth access, display warnings, engage consumers and facilitate purchase. Results can help public health educators and practitioners better understand tobacco marketing as a context for designing tobacco interventions.