Piler

Piler is an open-source email archival application designed to capture, store, index, and retrieve large volumes of email for compliance, eDiscovery, and long-term retention. It provides a searchable, tamper-evident archive with tools for import/export, access control, and audit logging.

Key Features

• Built-in SMTP archival server and support for ingest via MTA integration
• Archival and retention rules with legal-hold capabilities
• Message and attachment deduplication, compression, and optional encryption
• Digital fingerprinting and verification for tamper-evidence
• Full-text indexing with simple and expert search interfaces and saved searches
• Bulk import/export and message restore functionality (EML, Maildir, mailbox formats)
• Access control, audit logs, accounting, and search over audit records
• Authentication integrations: AD/LDAP, IMAP/POP3, SSO, and optional two-factor authentication
• Internationalization and customizable theming

Use Cases

• Regulatory compliance and tamper-evident long-term email retention for legal and audit requirements
• eDiscovery and internal investigations via fast full-text search and exportable message sets
• Reducing primary mailbox storage costs by offloading and deduplicating archived messages

Limitations and Considerations

• Large-scale deployments require careful planning of database, storage and indexing resources; bulk imports can be resource-intensive
• Search and indexing performance depend on chosen storage and indexing configuration and may need tuning for very large archives

Piler is suited for organizations that need a dedicated, auditable email archive with policy-driven retention and eDiscovery tools. It is flexible in ingestion methods and authentication integrations but benefits from capacity planning for high-volume environments.