mail-archiver

Open-source email archiving, honestly reviewed. No marketing fluff, just what you get when you self-host it.

TL;DR

• What it is: GPL-3.0-licensed web application for archiving, searching, and exporting emails from multiple accounts — IMAP, Microsoft 365, and import-only [1].
• Who it’s for: Small business owners, compliance-conscious founders, and teams who need a searchable, exportable email archive without paying per-user SaaS fees or handing their mail to a third party [1].
• Cost savings: Enterprise email archiving tools (Mimecast, Barracuda, Google Vault) run $3–10+/user/month. Mail-Archiver self-hosted runs on a $6–10/mo VPS with no per-user fees and no seat limits [1].
• Key strength: Covers the full archiving workflow — IMAP sync, M365 via Graph API, search, export to mbox/EML, retention policies, multi-user with audit logging — in a single Docker Compose deployment [1].
• Key weakness: 1,738 GitHub stars as of this review, solo maintainer, documentation described as “fresh and continuously being expanded” [1]. Independent third-party reviews are essentially nonexistent — this tool is niche enough that you’re mostly evaluating the README and deciding whether to trust a single developer’s project.

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What is Mail-Archiver

Mail-Archiver is a .NET web application that connects to your email accounts over IMAP or Microsoft Graph API, pulls down every message on a schedule, stores the content and attachments in a PostgreSQL database, and gives you a searchable web interface to browse, filter, export, and manage what it archived. The pitch on the GitHub README is plain: “A comprehensive solution for archiving, searching, and exporting emails” [1].

Three things make it worth knowing about. First, it handles Microsoft 365 natively via Graph API — not just IMAP. That’s a real difference from many self-hosted tools that stop at standard IMAP and leave M365 users to figure out an IMAP connector. Second, it has actual retention policy controls: you can tell it to automatically delete emails from your live mail server after 30, 90, or 365 days while keeping them in the archive forever. This is a compliance workflow, not just a backup. Third, it includes export to mbox and EML — standard formats that let you move your archive somewhere else if you ever want to. You’re not locked in.

The project sits at 1,738 stars and 58 forks as of this writing. It’s a solo-maintainer project, built by s1t5, with 372 commits on main. The license is GPL-3.0, which means you can self-host freely but cannot embed it in a proprietary product without open-sourcing your changes [1].

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Why people choose it

Independent reviews of Mail-Archiver specifically are scarce — the tool is niche enough that it hasn’t attracted the blogger attention that Nextcloud or Gitea get. The decision to choose it comes down to a comparison with the alternatives, not a community of vocal advocates.

The honest version of that comparison: every commercial email archiving solution is priced for enterprises, and the pricing scales with your headcount in ways that are painful for small teams.

Google Vault is part of Google Workspace, gated behind Business Plus ($18/user/month) or higher. If you’re paying for Business Starter ($6/user/month) — the most common tier for small teams — you don’t get Vault. Microsoft’s equivalent archiving features are locked behind M365 E3 ($22/user/month) or add-on compliance packs. Third-party tools like Mimecast and Barracuda list pricing by quote only, which tells you everything you need to know about who they’re selling to.

For a 10-person team, Google Vault alone requires upgrading your Workspace plan from $60/month to $180/month — a $120/month difference, or $1,440/year, just to get archiving. Mail-Archiver self-hosted on a $6/month VPS costs $72/year with no seat limits.

The people who reach for Mail-Archiver tend to fall into two camps: founders in regulated industries (legal, finance, healthcare) who need email retention for compliance reasons and don’t want to pay enterprise prices, and sysadmins at small organizations who want email archiving without adding another SaaS vendor to their stack.

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Features

Based on the README and GitHub repository:

Email account types supported:

• IMAP: any standard IMAP server with full folder sync [1]
• M365: Microsoft 365 via Microsoft Graph API (requires Azure app registration — a separate setup guide exists in the docs) [1]
• Import-only: for migrating existing archives into the system [1]

Archiving and sync:

• Scheduled synchronization of incoming and outgoing emails [1]
• Full attachment storage [1]
• Folder sync support [1]

Search and access:

• Full-text search across all archived emails with filtering [1]
• Email preview with attachment list [1]
• Export entire accounts as mbox files or zipped EML archives [1]
• Export of individual emails or selected batches [1]

Import and restore:

• MBox import and EML import (ZIP files with folder structure preserved) [1]
• Restore selected emails or entire mailboxes back to destination mail servers [1]

Retention policies:

• Per-account retention: auto-delete from live mail server after a configured number of days [1]
• Separate local archive retention: configure how long the archive itself keeps emails [1]

User management and security:

• Multi-user support with account-specific permissions [1]
• OpenID Connect (OIDC) for external authentication (Keycloak, Azure AD, etc.) [1]
• Comprehensive access logging: tracks access, export, deletion, restore, and other user actions [1]

Dashboard:

• Storage monitoring, statistics, sender analysis [1]

UI:

• Responsive, mobile-optimized, dark mode, multilingual [1]

What’s missing from the feature set: there’s no mention of email deduplication, no OCR for attachment content search, no legal hold or custodian workflow. These are enterprise compliance features — if your legal team is asking for them, Mail-Archiver isn’t the tool.

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Pricing: SaaS vs self-hosted math

Mail-Archiver has no SaaS tier. It’s a self-hosted-only project. The cost is the infrastructure you run it on.

Mail-Archiver self-hosted:

• Software: $0 (GPL-3.0) [1]
• VPS: $6–15/month depending on storage needs (Hetzner, Contabo, DigitalOcean)
• Your time to deploy and maintain it

Commercial alternatives for comparison:

Google Vault: Requires Google Workspace Business Plus at $18/user/month. A 10-person team: $180/month ($2,160/year). If you’re already on Business Plus for other reasons, Vault is included — factor that in.

Microsoft 365 archiving: Built-in archiving requires M365 E3 at $22/user/month or the Microsoft Purview add-on. 10 people: $220/month ($2,640/year).

Mimecast / Barracuda / Proofpoint: Enterprise pricing, quote-required. Publicly cited ballpark figures from resellers typically land $3–8/user/month for archiving-only tiers — data from public list prices is unavailable, as these vendors obscure pricing intentionally.

The concrete math for a 10-person team:

Option	Annual cost
Google Workspace Business Plus (Vault included)	~$2,160/year
M365 E3 (archiving included)	~$2,640/year
Mail-Archiver on a $10/mo VPS	~$120/year

The gap is real. If your only reason to be on a higher Workspace tier is archiving, and you’re comfortable with a Docker deployment, Mail-Archiver closes a $2,000/year gap.

Caveat: if you’re already on a higher-tier Workspace or M365 plan for unrelated reasons, the incremental cost of their built-in archiving is $0. Don’t pay $120/year for self-hosting complexity you don’t need.

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Deployment reality check

The Docker Compose path is straightforward. The repository provides a complete docker-compose.yml that spins up the app alongside PostgreSQL 17. The required environment variables are minimal: database connection string, admin credentials, and timezone [1].

What you actually need:

• A Linux VPS with enough storage for your email volume (start with 20–50GB for a small team)
• Docker and docker-compose
• A reverse proxy (Caddy or nginx) for HTTPS
• A domain name

The M365 path is more complex. Connecting a Microsoft 365 account requires registering an Azure app with the correct Graph API permissions — the docs include a setup guide, but it’s not a 10-minute click-through. Budget an extra hour if M365 is your target [1].

OIDC is available but optional. If you want to authenticate via Keycloak, Azure AD, or another OIDC provider instead of local credentials, there’s a guide for that too [1]. For a solo user or small team with no existing identity provider, the built-in username/password is fine.

Storage planning matters. Mail-Archiver stores email content and attachments in PostgreSQL. A team with 10 years of email history and heavy attachment use will accumulate significant database size. Plan your VPS storage accordingly and set up PostgreSQL backups — the project doesn’t bundle a backup solution.

What can go sideways:

• The documentation is the maintainer’s own words: “fresh and continuously being expanded” [1]. Expect some gaps. The GitHub Issues tracker is the support channel.
• Solo maintainer. If s1t5 stops maintaining the project, you’re holding a GPL codebase and responsible for your own patches. For a compliance-critical archive, that’s a real risk to weigh.
• No mention of database migration tooling or upgrade path documentation — something to verify before committing your email history to this system.

Realistic time estimate for a technical user who’s run Docker Compose before: 1–2 hours to a working IMAP setup. Add another 1–2 hours if you’re connecting M365 via Azure app registration. Non-technical users without Linux server experience should not attempt this without help.

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Pros and Cons

Pros

• GPL-3.0 license. Self-host freely, no commercial licensing conversation needed [1].
• M365 support via Graph API. Not all self-hosted email tools bother with this. If your team runs Microsoft 365, it works without hacking around IMAP compatibility [1].
• Complete audit logging. Access, export, deletion, restore — all tracked. For compliance use cases, this is the feature that makes it viable rather than just convenient [1].
• Retention policies with live mail server deletion. The ability to auto-purge emails from your live server after archiving them is a compliance workflow, not a backup feature. It’s included [1].
• mbox and EML export. Standard formats. Your data stays portable [1].
• OIDC support. If you already run Keycloak or another identity provider, you can integrate it [1].
• Single Docker Compose deployment. Low operational overhead compared to alternatives that require separate services [1].
• No per-user fees. Add 50 users or 5 — the infrastructure cost is the same [1].

Cons

• Solo maintainer, limited community. 1,738 stars is respectable for a niche tool, but it’s not the safety net of a multi-contributor project. If something breaks in an .NET upgrade, the fix timeline depends on one person [1].
• Documentation is incomplete. The maintainer flags this directly in the README. For a compliance-critical deployment, “documentation is still fresh” is a yellow flag [1].
• No deduplication, no legal hold, no custodian management. These enterprise compliance features don’t exist. If your legal team is asking for eDiscovery workflows, this isn’t the product [1].
• PostgreSQL stores everything including attachments. This works fine but means your database grows with every archived email. Backup and sizing discipline is entirely on you.
• No independent reviews. You’re trusting the README and the code. For a tool that holds your compliance archive, that’s a meaningful information gap.
• GPL-3.0 license restrictions. If you want to embed this in your own SaaS or managed service offering, GPL requires open-sourcing your changes. Not relevant for internal use, but worth knowing [1].

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Who should use this / who shouldn’t

Use Mail-Archiver if:

• You’re a small team or founder who needs email archiving for compliance and can’t justify $1,500+/year for a commercial solution.
• Your team uses IMAP-based email or Microsoft 365.
• You have (or can hire) someone comfortable with Docker Compose and Linux server basics.
• Data sovereignty matters — you want your email archive on your infrastructure, not a vendor’s.
• You’re okay accepting solo-maintainer risk for a non-customer-facing internal system.

Skip it if:

• Your compliance requirement comes with legal review, and legal needs a vendor with SLAs, SOC 2 certification, and a support contract. Mail-Archiver has none of these.
• You need eDiscovery features: legal hold, custodian management, chain of custody documentation.
• Your team has no technical resources. The deployment is approachable for a developer, not for a non-technical founder acting alone.
• You’re already on Google Workspace Business Plus or M365 E3 — the archiving you need is already included.

Stay on commercial tools if:

• You’re in a regulated industry with specific archiving standards (FINRA, SEC Rule 17a-4, HIPAA) that require certified archiving solutions. Self-hosted GPL software doesn’t come with certifications.

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Alternatives worth considering

• MailStore Home — free for personal use, Windows-only desktop app. Good for individuals, not teams, and doesn’t run as a server service.
• MailStore Server — commercial product from the same company as MailStore Home. Per-user pricing, proper Windows server deployment, support contracts available. The “grown-up” commercial alternative for teams that want self-managed archiving with vendor support.
• Google Vault — included in Workspace Business Plus ($18/user/month). Zero deployment complexity. If you’re already at that Workspace tier, there’s no reason to self-host.
• Microsoft Purview / M365 In-Place Archive — included in M365 E3 or higher. Same logic as Vault — if you’re already there, use it.
• Imapsync — not an archiver, but a tool for copying email between IMAP accounts. Useful for one-time migrations, not ongoing archiving.
• Dovecot with Pigeonhole/Sieve — for sysadmins who want to build their own archiving at the mail server level rather than run a separate archive application. More control, more work.

For a small team that wants a turnkey self-hosted option, the realistic shortlist is Mail-Archiver vs. MailStore Server. Mail-Archiver is free software that runs anywhere Docker runs; MailStore Server is a paid product with a Windows installer and actual vendor support. Pick your tradeoff: cost and flexibility vs. support and polish.

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Bottom line

Mail-Archiver fills a real gap: there is no well-funded open-source email archiving project with a large community and enterprise backing. Nextcloud has Nextcloud. Gitea has Gitea. Email archiving has Mail-Archiver and a handful of tools that stopped getting commits five years ago. For a team that needs scheduled email archiving, full-text search, mbox/EML export, retention policies, and audit logs — and doesn’t want to pay $150–200/month for a commercial solution — Mail-Archiver gets the job done. The risk is real: solo maintainer, incomplete documentation, no independent track record. Use it for internal archiving where a week of downtime to fix a broken update isn’t a catastrophe. Don’t use it as your primary compliance evidence store for an SEC audit.

If the deployment is the blocker, that’s exactly what upready.dev deploys for clients. One-time fee, done, you own the infrastructure.

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Sources

1. s1t5/mail-archiver — GitHub README and repository — primary source for features, architecture, deployment instructions, license (GPL-3.0), and project status. https://github.com/s1t5/mail-archiver

Note: No independent third-party reviews of Mail-Archiver were available at the time of writing. The five third-party sources provided during research covered unrelated topics (Postfix/Dovecot setup, email testing with Mailsac, musician email lists, SlickPic configuration, and Ubuntu mail server tutorials) and were not relevant to Mail-Archiver specifically. All feature and deployment claims in this review derive from the primary GitHub source above. Commercial pricing comparisons are based on publicly listed prices for Google Workspace and Microsoft 365 as of April 2026.