Turnitin - Turnitin is preferred by educational institutions around the world for preventing plagiarism. Instructors at all levels of education can request that students use the service to submit papers, and Turnitin checks those papers for plagiarism.

Editsaurus - Highlights potential pitfalls in your writing to encourage good habits.

Unicheck - The plagiarism checker Unplag scans across the internet, repositories, open sources content and databases. It delivers real-time results and has no cached data.

LanguageTool - Free proofreading tool for OpenOffice, LibreOffice, Firefox, and Chrome.

PlagiarismSearch - PlagiarismSearch is online service that detects plagiarized content.

Grammarian PRO3 - Grammarian PRO3 is a feature-rich grammar checker that enables you to write better content without taking assistance from the English teacher.