This chapter reviews the digital testing platforms for PIAAC and PISA as a means to provide general considerations when working with or designing a testing platform for an international or large-scale assessment. Such a platform needs to act as a hub for various functional purposes of the assessment and the communication between them. The test delivery system and questionnaire authoring tool are the primary focus, as they are the two most common and necessary components of digital testing platforms. In conjunction, these tools allow for accurate and efficient assessment creation, dissemination, and data collection, and may further provide users with the means to collaborate when the authoring tool is incorporated into a larger repository or communication system. Future innovations of large-scale assessments are also discussed, specifically in regard to new interactive item types and interfaces, the collection of log and process data, the incorporation of new test designs and automatic scoring, and the possibilities and limitations of web-based test administration.