GoVisually - GoVisually empowers creative teams to deliver better designs, by providing a simple way to review and approve designs quickly and easily

Papermind - Papermind Slack App is a collaborative article-editing and document management platform for Slack

Ziflow - Online Proofing software from Ziflow keeps teams connected and collaborating by providing a single source of truth for creative review and approval.

Quip: Team Documents for Slack - Create, share and get notified about Quip docs in Slack

PageProof - Online proofing of anything and everything, made simple. Streamline feedback for easy collaboration, secure workflows, and faster approvals. PageProof. The smarter way to review.

Workflowy - A better way to organize your mind.