Telstra partnered with Nokia to move away from siloed services and domains and towards flexible infrastructure. Telstra’s T25 strategy prioritises open technology and APIs, in recognition of the evolving needs of the digital age. The Telstra Reference Architecture Model (TRAM) has an API-first approach and is at the core of this strategy. TRAM creates modular building blocks (atomic services) for network and technology services, which can be easily combined to form new offerings. This case study provides: - an outline of Telstra's strategy - an overview of the business drivers behind the services architecture update - an overview of Telstra's partnership with Nokia - an analysis of the achieved business benefits.