Web-based molecule sketcher
Clone or download
Latest commit 8289009 Apr 3, 2018


EPAM Ketcher projects

Copyright (c) 2018 EPAM Systems, Inc

Ketcher is an open-source web-based chemical structure editor incorporating high performance, good portability, light weight, and ability to easily integrate into a custom web-application. Ketcher is designed for chemists, laboratory scientists and technicians who draw structures and reactions.


  • Fast 2D structure representation that satisfies common chemical drawing standards
  • 3D structure visualization
  • Draw and edit structures using major tools: Atom Tool, Bond Tool, and Template Tool
  • Template library (including custom and user's templates)
  • Add atom and bond basic properties and query features, add aliases and Generic groups
  • Select, modify, and erase connected and unconnected atoms and bonds using Selection Tool, or using Shift key
  • Simple Structure Clean up Tool (checks bonds length, angles and spatial arrangement of atoms) and Advanced Structure Clean up Tool (+ stereochemistry checking and structure layout)
  • Aromatize/De-aromatize Tool
  • Calculate CIP Descriptors Tool
  • Structure Check Tool
  • MW and Structure Parameters Calculate Tool
  • Stereochemistry support during editing, loading, and saving chemical structures
  • Storing history of actions, with the ability to rollback to previous state
  • Ability to load and save structures and reactions in MDL Molfile or RXN file format, InChI String, ChemAxon Extended SMILES, ChemAxon Extended CML file formats
  • Easy to use R-Group and S-Group tools (Generic, Multiple group, SRU polymer, peratom, Data S-Group)
  • Reaction Tool (reaction generating, manual and automatic atom-to-atom mapping)
  • Flip/Rotate Tool
  • Zoom in/out, hotkeys, cut/copy/paste
  • OCR - ability to recognize structures at pictures (image files) and reproduce them
  • Copy and paste between different chemical editors
  • Settings support (Rendering, Displaying, Debugging)
  • Use of SVG to achieve best quality in-browser chemical structure rendering
  • Languages: JavaScript with third-party libraries

Build instructions

Please read DEVNOTES.md for details.


Please read LICENSE and NOTICE for details.