Purpose: The purpose of this paper is to understand which controlling and enabling practices are used, how the numerous supplying partners are managed and how positive network effects are generated in online service triads (multi-sided platform – supplying partners – consumers). Design/methodology/approach: A single representative in-depth case study was conducted to refine theory on managing service triads. The main data source consists of field notes collected by one author, who held a temporary position within the organization. Additional data were collected from observations, internal documents, informal talks and 20 interviews. Findings: The authors found controlling and enabling organizational practices in four main categories on two levels as follows: managing network composition (system level), managing order fulfillment and returns (operations level), category management (both levels) and capability enhancement (both levels). Research limitations/implications: The authors show that both controlling and enabling practices are present in online service triads. This enables platform owners and supplying partners to share responsibilities for creating positive network effects, i.e. to increase scale, which increases value, which again attracts more suppliers and consumers, which creates more value, etc. Practical implications: The authors present a range of and controlling and enabling practices that describe how multi-sided platforms can manage numerous supplying partners in an online context. Originality/value: This study is the first to show that contractual and relational governance is insufficient in service triads in online settings with numerous supplying partners. Further, the authors provide empirical evidence that supply networks continuously adapt over time.