OEChem is a programming library for Chemistry and Chemical Informatics that is fast and has a stable, documented API. OEChem has many simple yet powerful functions, which handle the details of working with molecules. For routine tasks, OEChem offers clear and efficient scripting in Python. For more advanced software development, OEChem offers C++. High-level functions provide simplicity while low-level functions provide flexibility.

Key features of the OEChem Toolkit include:

• Facile management of molecules, atoms, bonds, and conformers
• Conformational and frame-of-reference molecular transformations
• Maximum common substructure and exact substructure searching
• Perception of aromaticity with multiple models
• Chemical reaction parsing and processing
• Tetrahedral and E/Z stereochemistry recognition
• Ring perception and Kekulization
• Molecular normalization and canonicalization
• Multiconformer molecule handling
• Support for residues and bases
• Safe and efficient memory management
• Ability to store and recall generic primitives or user-defined objects on molecules, atoms, bonds, or conformers
• Robust reading and specification-compliant writing of SMILES, SLN, SDF, MOL, MOL2, PDB, FASTA, MOPAC, MacroModel, XYZ, and OEBinary file formats
• Support for LINUX, HP-UX, Tru64UNIX, AIX, IRIX, Solaris, Windows, OS X (native or GNU g++ compilers)
• Support for 64-bit processing on HP-UX, Tru64UNIX, AIX, IRIX, Itanium®2 Linux and PowerPC Linux
• Supports POSIX pthreads and Win32 threads
• Available for commercial development projects
• Includes numerous examples, a.k.a. SCUT Monkeys; Training available