Open Archiver – Self-Hosted Email Archiving

TL;DR

TL;DR: Open Archiver is an open-source, self-hosted email archiving platform that ingests from Gmail, Microsoft 365, IMAP, and PST files; deduplicates and encrypts them; indexes full-text search via Meilisearch; and exposes compliance features like audit logs and integrity hashing.

What Is Open Archiver?

Open Archiver is a secure, sovereign, self-hosted email archiving platform built by LogicLabs-OU. It connects to Gmail, Microsoft 365, generic IMAP servers, and PST/MBOX files to create a permanent, tamper-proof record of your email history with full-text search across emails and attachments.

The project positions itself as a GDPR-compliant alternative to hosted email archiving services — no vendor lock-in, data stays on your own infrastructure.

Source and Accuracy Notes

• Project page: openarchiver.com
• Source repository: github.com/LogicLabs-OU/OpenArchiver
• License: GNU Affero General Public License v3 (verified via LICENSE file on main branch)
• Live demo: demo.openarchiver.com — [email protected] / openarchiver_demo
• HN launch thread: news.ycombinator.com/item?id=42918654
• Source last checked: 2026-08-14 (commit main)

Supported Email Sources

Open Archiver supports ingesting from multiple email platforms:

• Google Workspace (Gmail) via OAuth
• Microsoft 365 (Exchange Online)
• Generic IMAP servers
• PST files (Outlook data files)
• MBOX files and zipped .eml files

Synchronization can be one-time bulk import or continuous real-time sync. Deduplication runs on ingest to avoid storing duplicate emails.

Setup Workflow

Prerequisites

• Docker and Docker Compose
• A server with at least 4 GB RAM (2 GB if using external Postgres, Redis/Valkey, and Meilisearch instances)

Step 1: Clone and Configure

git clone https://github.com/LogicLabs-OU/OpenArchiver.git
cd OpenArchiver
cp .env.example .env
# Edit .env: set admin passwords and secret keys

Step 2: Start Services

docker compose up -d

All services — frontend (SvelteKit), backend (Node.js/Express/TypeScript), PostgreSQL, Redis/Valkey, and Meilisearch — start in the background.

Step 3: Access the UI and Configure an Ingestion Source

Navigate to http://localhost:3000. From the dashboard, add an ingestion source:

• For Google Workspace: follow the Google Workspace guide
• For Microsoft 365: follow the M365 guide
• For generic IMAP: follow the IMAP guide

Key Features

Storage format: Emails are stored as standard .eml files. The system deduplicates and compresses them, and all files are encrypted at rest. You can use local filesystem storage or any S3-compatible backend (AWS S3, MinIO, etc.).

Full-text search: Meilisearch indexes the full text of emails and attachments (PDF, DOCX). Search results are fast and relevance-ranked.

Compliance tooling:

• Per-email “Integrity Report” — stored SHA-256 hash lets you detect any file alteration after ingest
• Immutable audit trail logging every system access
• Granular retention policies per mailbox
• Legal hold support (TBD at time of writing)

Thread discovery: The system groups emails into conversations, so searching for a topic surfaces the full thread.

Architecture

The stack, confirmed from the README:

| Component | Technology | |---|---| | Frontend | SvelteKit with Svelte 5 | | Backend | Node.js, Express.js, TypeScript | | Job Queue | BullMQ on Redis/Valkey | | Search | Meilisearch | | Database | PostgreSQL (metadata, audit logs, user management) | | Deployment | Docker Compose |

Security Notes

• Files encrypted at rest
• SHA-256 hash stored for integrity verification
• Immutable audit log tracks all access
• OAuth2 integration for Google Workspace and Microsoft 365 — credentials are not stored locally
• Self-hosted means data never leaves your infrastructure

FAQ

Q: Does this replace my mail server? A: No. Open Archiver is a read-only archive. It ingests copies of emails from your existing mail server but does not handle sending or receiving.

Q: How does it handle attachment search? A: Meilisearch indexes the text content of PDF and DOCX attachments alongside the email body. Plain text and HTML emails are indexed natively.

Q: Is there a managed/hosted version? A: No. Open Archiver is fully self-hosted. There is no official hosted offering.

Q: What happens to attachments during deduplication? A: If the same attachment appears in multiple emails, only one copy is stored and referenced by each email record. This reduces storage without losing data.

Q: Can I export archived emails? A: Yes. Archived emails are standard .eml files on disk (or in S3), so they can be extracted directly from storage without needing the Open Archiver application.

Conclusion

Open Archiver fills a specific niche: teams that need email archiving sovereignty — legal compliance, tamper-proof storage, full-text search — without paying per-mailbox fees to a vendor. The Docker Compose setup is straightforward, the stack is modern (SvelteKit, TypeScript, Meilisearch), and the AGPLv3 license means you can inspect and modify everything.

If you are a law firm, regulated business, or anyone who needs long-term email preservation with e-discovery capability, it is worth a look. The live demo at demo.openarchiver.com lets you try the UI before committing to a self-hosted deployment.