Open Archiver
Open-source platform for legally compliant email archiving
2.2k stars 122 forks last commit first released AGPL-3.0
Actively maintained
Last commit 25 Jul 2026.
Open Archiver is an open-source platform designed to ingest, store, index and search email archives for compliance and e-discovery. It supports bulk imports and continuous synchronization from major providers and preserves emails in standard .eml format for tamper-evident records.
Key Features
- Universal ingestion: bulk import and continuous sync from IMAP, Google Workspace (Gmail), Microsoft 365, PST, mbox and zipped .eml files.
- Secure, deduplicated storage: stores original emails in .eml format with deduplication, compression and at-rest encryption (supports local filesystem and S3-compatible backends).
- Full-text indexing and search: indexes message text and common attachment types for high-performance search and e-discovery workflows.
- Thread discovery and context: groups related messages into conversation threads to present context during review.
- Integrity and auditing: computes file hashes and records integrity reports; maintains an immutable audit trail of system activities and accesses.
- Pluggable backends and async processing: uses job queues for ingestion and supports S3-compatible object storage for scalable deployments.
Use Cases
- Regulatory compliance and legal discovery: preserve corporate email archives and provide searchable records for audits and litigation.
- Long-term retention and corporate recordkeeping: centralized, tamper-evident storage of organizational communication history.
- Migration, forensic analysis and audits: bulk-import PST/mbox files and perform full-text searches across messages and attachments.
Limitations and Considerations
- Legal-hold controls are noted as "TBD" in the project documentation; organizations requiring built-in, mature legal-hold features should evaluate current status before relying on it for litigation holds.
Open Archiver is positioned as a modern, open-source tool for teams that need vendor-neutral email retention and searchable archives. A live demo and full installation instructions are provided by the project for evaluation and deployment.
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