The Modelica language is becoming increasingly popular among scientists and engineers as platform for modelling physical or biological systems. Although Modelica is maintained as non-proprietary language by the Modelica Association, a considerable number of commercial implementations and development environments is complemented by a surprisingly small number of open source tools.In this paper, we present the communication service Mo|E that connects any text editor as front-end with a Modelica compiler as back-end. Based on the simple HTTP communication protocol, editor plugins for a software developer's favourite text editor can be developed easily, hence turning any editor into a lightweight Modelica development tool.We also present a first implementation of a plugin for the text editor Atom that exhibits features necessary for efficient software development, such as display of compile errors, code completion, go to declaration or view of context-sensitive documentation. In addition, Modelicaspecific checking of the number of equations in a model is supported.