MEC 2021 BEST PAPER AWARD. Though MEI is widely used in music informatics and digital musicology research, the relative lack of authoring software and the specialised nature of its community have limited the availability of high-quality MEI encodings. Translating to MEI from other encoding formats, or generating MEI via optical music recognition processes, is thus a typical component of many MEI-project workflows. However, automated translations rarely achieve results of sufficient quality, a problem well-known in the community and documented in the literature. Final correction and validation by hand is therefore a common requirement. In this paper, we present meifriend, an extension to the Atom text editor, which aims to relieve the degree of manual labour required in this process. The tool facilitates most common MEI editing tasks including the insertion and manipulation of MEI elements, makes the encoded score visible and interactively accessible to the user, and provides quality-of-life conveniences including keyboard shortcuts for editing functions as well as intelligent navigation of the MEI hierarchy. We detail the tool’s implementation, describe its functionalities, and evaluate its responsiveness during the editing process, even when editing very large MEI files.