zipBoard, ProofHub, ReviewStudio, Ziflow, Moqhub, Filecamp.com, LookAt, Framebench, Aproove, TheCommentor, admation, Skwibl.com, Proofquick, ProofMe, ConceptShare, ProofCafe, Flatsies, MediaMarkup, Cozimo.com, Approval Manager are some alternatives to ProofHQ.