Engineering design review, which is a time-consuming task in the building permit process, faces challenges such as a scarcity of design review specialists, vulnerability to manipulation and corruption, and a lack of traceability and transparency. This paper explores the integration of blockchain and online service trading in addressing these challenges. This paper proposes a platform-based design review service trading scheme, engaging a distributed network of experts to overcome resource limitations and integrates blockchain technology to improve process traceability. The system model is presented, an access control model and a design version management method are proposed. A prototype system is developed, and a real-world project is used to illustrate the online design review process. Security, function, and performance evaluations show that the scheme is secure and efficient. This study highlights blockchain's potential in digital building permits. Future work can explore advanced service matching algorithms in online design review service trading platforms. •This study proposes a platform-based design review service trading scheme to engage a distributed network of design experts, aiming to overcome resource limitations.•The proposed scheme integrates blockchain technology to enhance immutability and traceability in the digital building permit process.•An access control model and design version management method are developed to achieve secure data transmission and trace design modifications in the design review process.•A real-world project is used as an example to simulated the proposed scheme.