E-health has been implemented internationally as a broad range of medical informatics applications for facilitating management and delivery of health care since the beginning of the 2000s. In Sweden, Mina VårdKontakter (Eng. My Health Care Contacts), is an e-healthplatform providing services nationally in all regions and county councils. In order to provide further features of the platform, third-party developers will be invited to develop parts and features of the system. The purpose of this thesis was to investigate the challenges and opportunities that third-party developers encounter as they aim to contribute to the platform and how the platform owner can provide support for the developers. In order to fulfill the purpose, five qualitative expert interviews were made with three third-party developer, one platform owner and one project manager. The main opportunity that the thirdparty developers saw was to gain financially from participating in the development of Mina VårdKontakter. The main challenge was the lack of access to real data, as opposed to demo-data, and the still not very developed support from the platform owner, such as the software development kit (SDK) and application programming interface (API). These and other platform boundary resources, such as agreements between developers and ownersstill need to be developed and communicated to the third-party developers.