Papermark is a secure virtual data room and document sharing platform for fundraising, M&A, due diligence, and confidential document sharing. It is open source and can be self-hosted.

Data rooms - permissioned rooms with NDA gating, dynamic watermarking, granular access, Q and A, and page-by-page analytics.
Document sharing - trackable links for individual files with password protection and custom domains.
AI assistant - chat with a data room with grounded answers, plus AI redaction.
Compliance - SOC 2 Type II, ISO 27001, GDPR, and EU data hosting with audit logs.
Developer access - a public API, CLI, and MCP server so deal teams and AI agents can run data rooms programmatically.

It is used by startup founders raising rounds, venture and private equity funds, M and A advisors, law firms, and sales teams sharing proposals.

Document sharing starts free, with Data Rooms from 99 euro per month and a 7-day free trial that needs no card.