This Practice Note provides practical guidance on the core UK legal, regulatory and compliance issues for business-to-business (B2B) digital commerce delivered through websites, platforms, mobile apps, portals, APIs/EDIs and related digital channels. It is drafted to support businesses selling goods and/or services to other businesses online, whether through standard form contracting, bespoke framework agreements or models such as Software-as-a-Service (SaaS). This Practice Note considers the regulation of information society services under the Electronic Commerce (EC Directive) Regulations 2002 (E-commerce Regulations 2002), SI 2002/2013, and the regulation of online platforms more widely. It provides a summary of key legal issues such as brand protection, website compliance, advertising and marketing, competition law, and signposts further detailed commentary throughout. For an introduction to digital commerce, including the types of platforms and technologies used, see Practice Note: Digital commerce—introduction. This Practice Note does not consider the formation and enforcement of online B2B contracts. For more information, see Practice Notes: Business-to-business digital commerce—forming contracts online and Digital commerce—website terms, policies and notices. Assimilated law Throughout this Practice Note, references