BEAM launched in early January and was the first full Mimblewimble implementation to go live, followed by Grin a couple of weeks later. The protocol for BEAM is written in C++ and expands on the original proposition of Mimblewimble with some additional features. Currently, a GUI wallet for users is available on MacOS, Windows, and Linux.
Development on BEAM was started later than Grin, beginning in March 2018, and has taken a more structured company approach — akin to ZCash — than Grin, which is largely driven by community-funded donations and a core team of developers who have been working with Mimblewimble since its original proposal. BEAM's focus is on providing a private store of value, tailored towards a user-friendly approach and a startup mindset.
BEAM has several features — both under development and working now — that expand on the original Mimblewimble design, including the use of transaction signing via the Schnorr protocol, opt-in auditability, Bright Boson (a working development for atomic swap support with Bitcoin), offline transactions, and hardware wallet integration as part of Bright Boson.
BEAM also emphasizes catering to businesses and separating the platform's development into two avenues: BEAM Core and BEAM Compliance. BEAM Core focuses on the technical innovation of the network's design while BEAM Compliance targets the opt-in compliance and auditability aspects of the network. BEAM Compliance is the segment of the project that caters directly to businesses looking for auditability for regulators or auditors while still retaining privacy as an optional feature.
The technical similarities between BEAM and Grin are apparent, as they are both Mimblewimble-based protocols, so evaluating the other areas in how they differ is the best means for distinguishing the two projects.