CSpell started out as an extension for VS Code: Code Spell Checker - Visual Studio Marketplace. When we started using VS Code, it did not have a spell checker. As a person that has trouble with spelling, I found this to be a great hinderance, thus the extension was born. At the suggestion of users, cspell was pulled out of the extension and into its own library and command line tools.


The goal was to have a fast spell checker that could check spelling as you type.

  • Fast - check as you type
  • Self-contained - a pure JS implementation - does not need external binaries or to talk to a web service.
  • Compact - the size of the spell checker should not be much bigger than the comparable Hunspell dictionary.
  • Configurable - much of CSpell is configured through cspell.json files.
  • Custom Dictionaries - custom dictionaries can be easily added and used.

Supporting Development