SemApps is a collaborative, interoperable, generic and modular knowledge management system : Based on linked data & semantic web technologies and the SOLID specification, it allows the co-production of knowledge graphs. Built on open standards, it enables the development of interoperable information systems. Designed on a modular architecture, it gives everyone the opportunity to build and customize platforms on demand. SemApps is an open-source software project whose development is coordinated by the Virtual Assembly (VA), a French-based non-profit organization bringing together about fifty developers and activists. In a context of strong fragmentation of dynamics in the field of transition, VA aims to develop commons (digital tools, methodologies and projects) to promote the interconnection of transition movements. SemApps is one of the Virtual Assembly's core projects. Its mission is to foster interconnections between communities by creating synergies between their information systems. SemApps is a collaborative, interoperable, generic and modular knowledge management system : - Based on semantic web technologies and the SOLID specification, it allows the co-production of knowledge graphs. - Built on open standards, it enables the development of interoperable information systems. - Designed on a modular architecture, it gives everyone the opportunity to build and customize platforms on demand. Its code is released under the Apache 2.0 free license.