Mr. Allen's practice includes utility patent and design patent work in a wide variety of technologies, including tactical gear (e.g., equipment for use by military, militia, or law enforcement personnel), camping equipment, outdoor and sporting goods, knives, datacenter infrastructure, HVAC and thermal load management, warehouse management and automation, order fulfillment logistics, robotics, 3D printing, aerospace, oilfield drilling and related services, consumer machinery and products, manufacturing machinery and processes, textiles, footwear, garments, buckles and other attachment systems, construction tools, retail infrastructure, clean energy, storm drainage, cushions, boats, surgical implants and methodology, and other mechanical and medical devices and the controllers for such devices.

Mr. Allen is actively involved in pro bono work. He works with pro bono clients in a variety of matters, including immigration work (e.g., Temporary Protected Status (TPS), U-Visa, and asylum cases). He has volunteered frequently at legal clinics including at an organization that focuses on serving the local homeless population and another that focuses on serving the local Latino population. In addition to his pro bono work, he also devotes a significant amount of time to his community in the Rainier Beach neighborhood in the southern area of Seattle.

Mr. Allen was recognized in the 2025 listing and the four years immediately preceding as one of the "Best Lawyers: Ones to Watch" for Intellectual Property Law by The Best Lawyers in America®. He was also recognized as a Washington "Rising Star" in 2023 and 2024 for Intellectual Property by Super Lawyers magazine.

Mr. Allen is fluent in Spanish.