Most international attendees require a US visa. B-1 temporary business visitor status applies to conference attendance and professional meetings; eligible Visa Waiver Program nationals can travel under ESTA instead, and Canadian citizens generally do not need a visa for business visits.
Estimated cost: Check the State Department MRV fee schedule for the B-1 business visitor category; fees are set by the US government and change periodically.
Processing: Interview appointment backlogs differ substantially between consular posts; build several weeks to months of lead time and check your local embassy or consulate schedule.
Bring the CODE EMS Conference registration confirmation and an employer letter stating your role and purpose of travel. The B-1 fact sheet at travel.state.gov/content/travel/en/us-visas/business/b-1-fact-sheet.html sets out which business activities are allowed.
Official