Best Self Hosted Alternatives to Proton Mail

Stalwart is a modern, self-contained email server designed to run a complete mail stack (sending, receiving, and mailbox access) with strong security controls and built-in filtering. It aims to simplify operating mail infrastructure by bundling protocols, authentication, policy, and anti-abuse features into a single service with an administrative UI.

Key Features:

• Supports core mail access and transport protocols including SMTP and IMAP, with JMAP support for modern clients
• Built-in anti-spam and policy enforcement with rules, reputation controls, and content filtering
• Email authentication features such as DKIM signing and DMARC/SPF evaluation to improve deliverability and prevent spoofing
• Flexible message routing, domain/user management, and multi-domain support for organizations
• Web-based administration interface for configuration and operational management
• TLS support and modern security defaults oriented toward safer deployments

Use Cases:

• Run a private email service for a personal domain or small organization
• Replace a hosted mailbox provider while keeping control of deliverability and anti-spam
• Operate multi-tenant email for multiple domains with centralized management

Stalwart provides a cohesive, security-focused approach to running email by combining protocols, filtering, and administration in one package. It is well-suited for operators who want a modern mail stack with fewer external components to integrate and maintain.

Mailu is a full mail server stack distributed as a set of Docker containers, providing SMTP and IMAP services plus webmail and administration. It aims to make running a secure, standards-compliant email server easier by bundling the common components and exposing a web UI for daily management.

Key Features

• Complete mail stack in containers: SMTP (Postfix), IMAP (Dovecot), and web front-end services
• Web administration interface to manage domains, users/mailboxes, aliases, and credentials
• Built-in anti-spam and content filtering using Rspamd (with milter integration)
• Optional antivirus scanning via ClamAV
• Email authentication support (e.g., DKIM signing via OpenDKIM; DMARC-related configuration documented)
• Webmail via Roundcube (optional) and support for additional services depending on deployment profile
• Multiple deployment options and profiles (e.g., docker-compose; behind reverse proxies such as Traefik)

Use Cases

• Self-managed email hosting for a personal domain (mailboxes and aliases)
• Small organization mail service with web-based administration and spam/virus filtering
• Lab/home server mail stack for learning and testing SMTP/IMAP, DKIM, and anti-spam configuration

Limitations and Considerations

• Operating a deliverable email service requires correct DNS configuration (MX, SPF, DKIM, DMARC) and ongoing reputation/anti-abuse management
• Some features depend on optional containers/services (e.g., webmail, antivirus), increasing resource usage and operational complexity

Mailu provides an integrated, container-first approach to email hosting that combines the core MTAs/IMAP server with a management UI and anti-spam/AV components. It is a practical choice when you want a cohesive, well-known mail stack with minimal manual wiring between services.

Roundcube is a browser-based IMAP email client designed to provide a full-featured webmail experience on top of existing mail servers (IMAP/SMTP). It focuses on a clean UI, standards-based email handling, and extensibility via plugins and skins.

Key Features

• IMAP webmail UI with message list, conversation-style viewing, and folder management
• SMTP sending with support for multiple sender identities and per-identity settings
• Address book with groups and LDAP integration via plugins (commonly deployed)
• Powerful search and message filtering capabilities (server-dependent; supports standard IMAP search)
• MIME and HTML email rendering with attachment handling
• Sieve / ManageSieve integration via plugin for server-side mail filtering rules
• Extensible architecture: plugin API, skinning system, localization, and theming
• PGP support available through plugins (e.g., Enigma/PGP-related plugin ecosystems depending on deployment)

Use Cases

• Provide webmail access for a Postfix/Dovecot-based email domain without outsourcing to hosted webmail
• Offer a lightweight, user-friendly mailbox interface for small organizations, ISPs, and homelabs
• Add server-side filtering (Sieve) management to an existing IMAP service via plugins

Limitations and Considerations

• Not a full groupware suite by default; calendars/contacts sync and advanced collaboration typically require plugins and/or external services
• Feature depth depends on IMAP server capabilities and installed plugins (e.g., Sieve, LDAP)

Roundcube is a mature, widely deployed webmail client that integrates with standard mail server stacks. Its plugin and theming ecosystem makes it adaptable for many email hosting scenarios while keeping the core focused on webmail.

Mox is an all-in-one email server focused on being easier to run and safer by default than traditional “glue-it-together” mail stacks. It provides SMTP submission/receiving and IMAP access, a built-in admin web interface, and sensible defaults for modern email authentication and deliverability.

Key Features

• Integrated SMTP server (incoming + submission) and IMAP server
• Built-in admin web UI for managing domains, accounts, and operational settings
• Automatic TLS certificate provisioning via ACME
• Modern email authentication and policy support (DKIM signing, SPF/DMARC evaluation)
• Spam filtering controls (including common DNSBL-style checks) and delivery safeguards
• Mailbox storage and indexing handled by Mox (no external IMAP/SMTP components required)
• Operational tooling for diagnostics/logging and safer configuration changes

Use Cases

• Host email for a personal domain or small organization with a single, cohesive server
• Replace a multi-component Postfix/Dovecot stack with an integrated setup
• Run a mail server with modern authentication defaults for better deliverability

Limitations and Considerations

• Not a full groupware suite (no calendars/contacts as a primary feature)
• Self-hosted email deliverability depends on correct DNS and IP reputation

Mox aims to reduce complexity by shipping a cohesive mail server with an admin UI and modern defaults. It’s best suited for operators who want a straightforward, integrated email stack while retaining control over their domains and accounts.

AnonAddy is a self-hostable email aliasing and forwarding platform that lets you create unique alias addresses and route incoming mail to one or more real inboxes. It is designed to reduce spam, prevent tracking across services, and give you control over how others can contact you.

Key Features

• Create and manage email aliases (standard aliases and catch-all/domain aliases)
• Forward incoming email to verified recipient addresses
• Reply/send from an alias (so your real address stays hidden)
• Custom domains and domain-wide catch-all support
• Turn aliases on/off and delete them to stop unwanted mail
• SMTP/transport integration intended for running with a mail stack (e.g., Postfix) and DNS records (SPF/DKIM/DMARC) for deliverability
• API and web UI for alias lifecycle management and automation
• Browser extension and integration options (for quickly generating/using aliases)

Use Cases

• Use unique aliases per website to identify and block data leaks or spam sources
• Create role-based aliases (e.g., billing@, support@) that forward to personal/team inboxes
• Shield your primary inbox when signing up for newsletters, trials, and one-off services

Limitations and Considerations

• Requires correct mail/DNS configuration (MX, SPF, DKIM, DMARC) to ensure reliable delivery and sending
• “Send/reply as alias” depends on outbound mail setup and can be impacted by provider policies and deliverability constraints

AnonAddy is a strong choice for privacy-focused email workflows where you want fine-grained control over inbound addresses, simple alias management, and the ability to respond without revealing your real mailbox. It can be operated with your own domain(s) to fully own your addressing and reduce long-term spam exposure.

SnappyMail is a self-hosted webmail client designed to provide a fast, modern email interface for existing mail servers via IMAP and SMTP. It is a community-driven continuation/fork of RainLoop, focusing on performance, security improvements, and compatibility with common mail setups.

Key Features

• IMAP mail access and SMTP sending (works with most existing mail providers/servers)
• Responsive, single-page web UI with keyboard shortcuts and conversation/thread view
• Sieve filtering support (manage server-side mail filtering rules where supported)
• PGP/GPG message encryption and signing support (via OpenPGP integration)
• Multiple accounts/identities and folder management
• Attachment handling, message search, and rich message viewing
• Admin panel for domain/account configuration and application settings
• Plugin/extension mechanism (feature set depends on enabled plugins)

Use Cases

• Provide a modern webmail UI for Postfix/Dovecot (or any IMAP/SMTP) mailboxes
• Offer browser-based email access for small teams without adopting a full groupware suite
• Replace hosted webmail UIs while keeping the existing mail server stack

Limitations and Considerations

• Not a mail server: requires external IMAP/SMTP services to function
• Some advanced capabilities depend on server support (e.g., Sieve availability)

SnappyMail is a good fit when you want a modern, performant webmail experience while retaining your current mail infrastructure. It targets practical administration and end-user usability without the operational overhead of a full email/groupware platform.

Dovecot is a high-performance IMAP and POP3 server used to provide mailbox access for email users and clients. It is widely deployed with MTAs such as Postfix or Exim and supports common mailbox formats and authentication backends.

Key Features

• IMAP4rev1 and POP3 server with TLS/SSL support
• High-performance mailbox index/cache architecture for fast access
• Supports Maildir and mbox (and can integrate with other storage via plugins)
• Authentication framework with multiple backends (e.g., PAM, LDAP, SQL) and pluggable mechanisms
• SASL integration commonly used by Postfix for SMTP authentication
• Quota and ACL support (IMAP ACL) for shared mailboxes and access control
• Sieve mail filtering via Pigeonhole (separate but commonly paired component)
• Replication and high-availability options (dsync-based replication)

Use Cases

• Provide IMAP/POP3 access for a self-managed email domain (paired with Postfix/Exim)
• Centralized authentication for mail services (LDAP/SQL/PAM) with per-user mail storage
• Shared mailboxes and delegated access scenarios (teams/support mailboxes)

Limitations and Considerations

• Not a full email stack by itself: you typically pair it with an MTA (e.g., Postfix) and optional anti-spam/AV components
• Some advanced functionality (e.g., Sieve filtering) is delivered via companion projects/plugins (not strictly in the core daemon)

Dovecot is a mature, widely used mailbox-access server emphasizing speed, interoperability, and flexible authentication/storage integrations. It fits well in production mail setups where IMAP/POP3 reliability and performance are critical components.