Since the 18th century, States have established international courts and tribunals (ICTs) to resolve impasses when drafting treaty terms. To settle these uncertainties in subsequent cases, ICTs assert powers beyond those expressed in the skeletal terms of their constitutive treaties. These assertions are often based on the premise that such powers are inherent to the judicial function. Today, the ambiguity of inherent powers leads to accusations of judicial overreach at ICTs — from the World Trade Organization to the International Criminal Court, regional human rights courts to investor-State arbitration. By relying on empirical data to anchor the powers of ICTs in recognised sources of international law, Leiden University’s Tracing Inherent Powers project aims to improve stakeholder trust and efficiency during negotiations on the constitution (and reform) of ICTs. The Tracing Inherent Powers project pursues three research tracks corresponding to the sources of international law formally recognised by States: treaties, customary international law, and general principles of law. Because ‘general principles of law’ are transposed from municipal legal systems, the project is recruiting Associated Experts to canvass data on judicial practice in a vast range of jurisdictions. This is the current function of inherentpowers.com. Working with project leadership, Associated Experts around the world systematically survey the exercise and rationalisation of uncodified powers by domestic courts. As these findings are synthesised in an international policymaker handbook and peer-reviewed socio-legal publications, the surveys are made publicly (and permanently) available to academics and practitioners in an indexed, searchable database. That is the future of inherentpowers.com.