The Postmark Challenge: Inbox Innovators is an open-source developer challenge that invites participants to create innovative applications using Postmark's Inbound Email Processing feature. The challenge officially starts on May 21st, 2025, and winners will receive $3,000 in prizes, including DEV++ Membership, exclusive recognition, and a completion badge on their DEV profile. Participants are encouraged to explore the possibilities of inbound email and showcase the creative power of the developer community. The challenge aims to encourage innovation, creativity, and problem-solving skills among developers. To participate, individuals must have a Postmark account, which includes a free trial with up to 100 inbound emails per month. The submission requirements are simple: build something that incorporates Postmark's Inbound Email parsing feature.