Background: For the past twenty-five years, sex workers have been using Information and Communication Technologies, such as the Internet, websites, emails, blogs, texting, mobile phones, and social media, to receive and exchange occupational health and safety information. However, previous research has indicated that sex workers would prefer to use a sex worker-only digital occupational health and safety tool, designed by sex workers for sex workers. By forming an alliance with technologists and researchers, sex workers can design a digital platform that can meet their occupational health and safety needs by using a collaborative and participatory approach known as co-design. Objective: In applying the practice of co-design to create a digital prototype, we sought to answer the following research question “What are the core components of a digital tool that will enable the delivery of occupational health and safety strategies for sex workers?” Methods: Using the Auckland District Health Board of New Zealand's Health Service Co-design framework, three co-design sessions were held. Due to the COVID-19 pandemic, the three co-design sessions for this study were held virtually. Results: A total of 6 sex workers from 4 Eastern Canadian cities participated in 3 co-design sessions. During the first session, journey mapping, participants sketched out their stories by discussing their experiences using various digital tools (e.g., group chats) to exchange safety tips. In the second session, participants used outputs from the first session to further discuss their needs and develop scenarios, sketching the steps they would take to access a digital occupational health and safety resource. During the third session, participants used outputs from the prior sessions to formulate the core components of the digital tool. The resulting prototype, a website participants named SWanswers (Sex Work answers), was comprised of 6 core components: regional bad date resources, the work of sex work, supplies, STI information and education, sexual health, and harm reduction services. Conclusion: Findings from the co-design approach employed in this study could help guide sex workers, academics, and technologists when collaborating on digital health endeavours.