When a regulatory audit, legal discovery request, or employee offboarding requires years of verifiable email records, Open Archiver provides a tamper-evident, self-hosted vault for every message across your organization. Connect Google Workspace domains, Microsoft 365 tenants, personal Outlook OAuth accounts, or standard IMAP servers for continuous background synchronization, or upload historical PST, MBOX, and zipped EML archives in bulk. Every ingested message is deduplicated, compressed, and stored in standard EML format on local disks or S3-compatible object storage while SHA-256 cryptographic hashes verify file authenticity on demand through built-in Integrity Reports. Instant full-text search scans both message bodies and attached PDF or DOCX documents, letting compliance teams reconstruct complete conversation threads and enforce automated retention policies. Granular access control backed by an AWS IAM style policy engine, TOTP two-factor authentication, and an immutable audit trail keeps sensitive correspondence locked down. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. AGPL-3.0 licensed.