<p>In edge computing, the diversity of scenarios makes it difficult for a single authentication protocol to extend to different scenarios, which leads to the scalability issue of a single authentication protocol. On the other hand, with the rapid increase in the number of edge devices, different authentication protocols are adopted among diverse devices, which makes it difficult to achieve mutual authentication, and brings about the heterogeneity issue of authentication protocols. To tackle the aforementioned challenges of scalability and heterogeneity in authentication protocols, this paper proposes a scalable heterogeneous authentication protocol based on JSON Web Token (JWT), namely APSH-JWT. JWT is a secure transmission tool based on JSON format. APSH-JWT leverages JWT to replace traditional session-based authentication, enabling the addition of custom claims to the Payload structure without altering the core protocol flow. This adaptation empowers a single authentication protocol to be universally applicable across diverse scenarios, effectively resolving scalability concerns. Additionally, APSH-JWT adopts XML encoding to further enhance support for the JWT format, addressing the heterogeneity issue in authentication protocols among different devices caused by differences in encoding formats, thereby enabling mutual authentication. Furthermore, APSH-JWT employs the lightweight cryptographic algorithm Authenticated Sponge Construction (ASCON) to encrypt the Payload structure, enhancing the protection of user identity privacy. Through comprehensive performance analysis and testing from multiple perspectives, including computing cost, communication cost, scalability, and heterogeneity, APSH-JWT can draw the conclusion that it exhibits excellent experimental performance in all aspects, thereby achieving the flexibility goal required by the authentication protocol in edge computing.</p>