PDF Reviewer is a web-based document collaboration platform built for teams who review, markup, and approve PDFs, 3D models, and technical drawings. Designed for architecture, engineering, construction, and research teams, it streamlines design coordination with advanced spatial commenting, version-aware approval workflows, and real-time collaboration. Unlike desktop software, PDF Reviewer runs 100% in your browser—no installation required. Review native STEP and GLB files up to 500MB alongside PDFs in unified projects. Track RFIs, manage multi-stage approvals, and coordinate feedback across disciplines with complete audit trails. First 2 seats free forever, additional seats just $9/month with no annual contracts. Save 67-94% vs enterprise alternatives while getting purpose-built document review tools, not project management bloat. Perfect for external consultants, clients, and field teams—guest access via temporary links requires no account.