The HELM editor allows the user to create and manipulate large macromolecules. You can import and export in a variety of formats, but HELM underlies the internal processes.
This editor only supports HELM1 and has been superseded by the web-editor which supports both HELM1 and 2.
In 2014 a student from Cambridge University created a proof of concept to demonstrate how searching could be implemented in HELM. It showed how you could search structural elements using exact match and substructure searches and sequence level searches. The code is available, but there is a minimal user interface, so further work is required to make it into a fully functioning tool.
Between March and May 2016 a group of students at Harvard University created a web-editor for HELM as a project assignment for their course. The report, a demo version and links to the code are all below.