WProofreader is a multilingual grammar checker to integrate with HTML controls and WYSIWYG editors. Available as an add-on for Chrome, Firefox, and Microsoft Edge. WProofreader is a portfolio of multilingual sentence check solutions helping individuals and businesses to enrich the functionality of web applications and custom systems. The portfolio includes WProofreader Software Development Kit (SDK) and WProofreader browser extension. The SDK consists of predefined plugins for HTML controls and WYSIWYG editors and a standalone HTTP API. WProofreader sentence corrector supports 20+ languages, incl. AI English, German, Spanish. Enhanced security, on-premise deployment, language autodetect, spelling autocorrect, autocomplete suggestions, accessibility, customization, spelling dictionaries. WProofreader is also available as an in-browser extension for Chrome, Firefox, and Microsoft Edge.