diff --git a/hieradata/common.yaml b/hieradata/common.yaml
index 7ca2200..bda632d 100644
--- a/hieradata/common.yaml
+++ b/hieradata/common.yaml
@@ -167,6 +167,10 @@ lookup_options:
   postfix::virtuals:
     merge:
       strategy: deep
+  stalwart::postgresql_password:
+    convert_to: Sensitive
+  stalwart::s3_secret_key:
+    convert_to: Sensitive
 
 facts_path: '/opt/puppetlabs/facter/facts.d'
 
diff --git a/hieradata/roles/infra/mail/backend.eyaml b/hieradata/roles/infra/mail/backend.eyaml
new file mode 100644
index 0000000..2cd3885
--- /dev/null
+++ b/hieradata/roles/infra/mail/backend.eyaml
@@ -0,0 +1,4 @@
+---
+profiles::sql::postgresdb::dbpass: ENC[PKCS7,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]
+stalwart::s3_access_key: ENC[PKCS7,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]
+stalwart::s3_secret_key: ENC[PKCS7,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]
diff --git a/hieradata/roles/infra/mail/backend.yaml b/hieradata/roles/infra/mail/backend.yaml
new file mode 100644
index 0000000..73501b3
--- /dev/null
+++ b/hieradata/roles/infra/mail/backend.yaml
@@ -0,0 +1,39 @@
+---
+hiera_include:
+  - stalwart
+  - profiles::sql::postgresdb
+
+# additional altnames
+profiles::pki::vault::alt_names:
+  - mail.main.unkin.net
+  - imap.main.unkin.net
+
+# manage a pgsql database + user
+profiles::sql::postgresdb::cluster_name: "patroni-shared-%{facts.environment}"
+profiles::sql::postgresdb::dbname: stalwart
+profiles::sql::postgresdb::dbuser: stalwart
+
+
+# Cluster role for node discovery
+stalwart::cluster_role: "%{facts.enc_role}"
+
+# PostgreSQL connection
+stalwart::postgresql_host: "master.%{hiera('profiles::sql::postgresdb::cluster_name')}.service.%{facts.country}-%{facts.region}.consul"
+stalwart::postgresql_database: "%{hiera('profiles::sql::postgresdb::dbname')}"
+stalwart::postgresql_user: "%{hiera('profiles::sql::postgresdb::dbuser')}"
+stalwart::postgresql_password: "%{hiera('profiles::sql::postgresdb::dbpass')}"
+
+# S3/Ceph-RGW connection
+stalwart::s3_endpoint: 'https://radosgw.service.consul'
+stalwart::s3_bucket: 'stalwart-maildata'
+stalwart::s3_region: "%{facts.region}"
+
+# Domains and relay
+stalwart::domains:
+  - 'mail.unkin.net'
+stalwart::postfix_relay_host: 'out-mta.main.unkin.net'
+stalwart::manage_dns_records: true   # DNS records point to individual servers
+
+## With load balancer:
+#stalwart::manage_dns_records: true
+#stalwart::loadbalancer_host: 'mail-lb.example.com'
diff --git a/modules/stalwart/README.md b/modules/stalwart/README.md
new file mode 100644
index 0000000..49960d1
--- /dev/null
+++ b/modules/stalwart/README.md
@@ -0,0 +1,213 @@
+# Stalwart Mail Server Module
+
+This Puppet module manages Stalwart Mail Server, a modern, secure, and scalable mail server implementation that supports IMAP, JMAP, WebDAV, and SMTP protocols.
+
+## Overview
+
+The `stalwart` module provides a comprehensive solution for deploying Stalwart Mail Server in a clustered environment with:
+
+- **PostgreSQL backend** for data, full-text search, and in-memory storage
+- **S3/Ceph-RGW backend** for blob storage (emails, attachments, sieve scripts)
+- **Automatic cluster discovery** using `query_nodes()`
+- **DNS autodiscovery records** for email client configuration
+- **TLS certificate management** integration
+- **Postfix relay integration** for SMTP routing
+
+## Features
+
+- ✅ **Multi-node clustering** with peer-to-peer coordination
+- ✅ **PostgreSQL authentication** with SQL directory backend
+- ✅ **S3 blob storage** with compression support
+- ✅ **IMAP/IMAPS protocols** for email access
+- ✅ **HTTP/HTTPS protocols** for JMAP, WebDAV, and autodiscovery
+- ✅ **SMTP relay** for postfix integration
+- ✅ **DNS autodiscovery** record management
+- ✅ **Automatic role distribution** across cluster nodes
+- ✅ **TLS security** with Vault PKI integration
+
+## Requirements
+
+- **Puppet 6+** with `query_nodes()` function support
+- **Stalwart RPM package** (creates user, directories, systemd service)
+- **PostgreSQL cluster** for data storage
+- **S3-compatible storage** (Ceph-RGW, MinIO, AWS S3)
+- **DNS management** via `profiles::dns::record`
+- **PKI management** via `profiles::pki::vault::alt_names`
+
+## Usage
+
+### Recommended Usage with Role
+
+The recommended way to use this module is via the `roles::infra::mail::backend` role with hieradata configuration:
+
+```puppet
+include roles::infra::mail::backend
+```
+
+Configure all parameters in `hieradata/roles/infra/mail/backend.yaml` - see `examples/role-hieradata.yaml` for a complete example.
+
+### Direct Class Usage
+
+```puppet
+class { 'stalwart':
+  node_id             => 1,
+  cluster_role        => 'mail-backend',
+  postgresql_host     => 'pgsql.example.com',
+  postgresql_database => 'stalwart',
+  postgresql_user     => 'stalwart',
+  postgresql_password => Sensitive('secretpassword'),
+  s3_endpoint         => 'https://ceph-rgw.example.com',
+  s3_bucket           => 'stalwart-blobs',
+  s3_access_key       => 'accesskey',
+  s3_secret_key       => Sensitive('secretkey'),
+  domains             => ['example.com'],
+  postfix_relay_host  => 'postfix.example.com',
+}
+```
+
+## Hieradata Configuration
+
+See `examples/role-hieradata.yaml` for a complete example of role-based hieradata configuration.
+
+### Required Parameters
+
+```yaml
+# Cluster role for node discovery
+stalwart::cluster_role: 'mail-backend'
+
+# Optional: Unique node identifier (auto-calculated if not specified)
+# stalwart::node_id: 1
+
+# PostgreSQL connection
+stalwart::postgresql_host: 'pgsql.example.com'
+stalwart::postgresql_database: 'stalwart'
+stalwart::postgresql_user: 'stalwart'
+stalwart::postgresql_password: >
+  ENC[PKCS7,encrypted_password...]
+
+# S3/Ceph-RGW connection
+stalwart::s3_endpoint: 'https://ceph-rgw.example.com'
+stalwart::s3_bucket: 'stalwart-blobs'
+stalwart::s3_access_key: 'access_key'
+stalwart::s3_secret_key: >
+  ENC[PKCS7,encrypted_secret...]
+
+# Domains and relay
+stalwart::domains:
+  - 'example.com'
+stalwart::postfix_relay_host: 'postfix.example.com'
+```
+
+## Architecture
+
+### Cluster Setup
+
+The module automatically discovers cluster members using `query_nodes()` based on:
+- `enc_role` matching `cluster_role` parameter
+- `country` fact matching the node's country fact
+- `region` fact matching the node's region fact
+
+**Node ID Assignment:**
+- Node IDs are **automatically extracted** from the last 4 digits of the hostname
+- Example: `ausyd1nxvm1234` → node ID `1234`
+- Manual override available via `stalwart::node_id` parameter if needed
+- Hostname must end with 4 digits for automatic extraction to work
+- Ensures unique IDs when following consistent hostname patterns
+
+### Storage Layout
+
+- **Data Store**: PostgreSQL (metadata, folders, settings)
+- **Full-Text Search**: PostgreSQL (search indexes)
+- **In-Memory Store**: PostgreSQL (caching, sessions)
+- **Blob Store**: S3/Ceph-RGW (emails, attachments, files)
+
+### Directory Structure (Created by RPM)
+
+- **Config**: `/opt/stalwart/etc/config.toml`
+- **Data**: `/var/lib/stalwart/` (queue, reports)
+- **Logs**: `/var/log/stalwart/stalwart.log`
+- **Binary**: `/opt/stalwart/bin/stalwart`
+- **User**: `stalwart:stalwart` (system user)
+
+### Network Ports
+
+- **143**: IMAP (STARTTLS)
+- **993**: IMAPS (implicit TLS)
+- **443**: HTTPS (JMAP, WebDAV, autodiscovery)
+- **2525**: SMTP relay (postfix communication)
+- **11200**: Cluster coordination (peer-to-peer)
+- **9090**: Prometheus metrics
+
+### DNS Records
+
+When `manage_dns_records: true`, the module creates:
+- `autoconfig.domain.com` → server FQDN (Thunderbird)
+- `autodiscover.domain.com` → server FQDN (Outlook)
+- `_imap._tcp.domain.com` SRV record
+- `_imaps._tcp.domain.com` SRV record
+- `_caldav._tcp.domain.com` SRV record
+- `_carddav._tcp.domain.com` SRV record
+
+## PostgreSQL Schema
+
+The module expects these tables in the PostgreSQL database:
+
+```sql
+CREATE TABLE accounts (
+  name TEXT PRIMARY KEY,
+  secret TEXT,
+  description TEXT,
+  type TEXT NOT NULL,
+  quota INTEGER DEFAULT 0,
+  active BOOLEAN DEFAULT true
+);
+
+CREATE TABLE group_members (
+  name TEXT NOT NULL,
+  member_of TEXT NOT NULL,
+  PRIMARY KEY (name, member_of)
+);
+
+CREATE TABLE emails (
+  name TEXT NOT NULL,
+  address TEXT NOT NULL,
+  type TEXT,
+  PRIMARY KEY (name, address)
+);
+```
+
+## Security
+
+- **TLS required** for all connections
+- **PostgreSQL SSL** enabled by default
+- **S3 HTTPS** endpoints required
+- **Password hashing** supported (SHA512, BCRYPT, etc.)
+- **Certificate management** via Vault PKI
+
+## Monitoring
+
+- **Prometheus metrics** on port 9090
+- **Log files** in `/var/log/stalwart/`
+- **Queue monitoring** in `/var/lib/stalwart/queue/`
+- **Service status** via systemd (`stalwart.service`)
+
+## Troubleshooting
+
+### Cluster Formation Issues
+- Verify `query_nodes()` returns expected nodes
+- Check `country` and `region` facts are consistent
+- Ensure `cluster_role` matches across all nodes
+
+### Storage Connection Issues
+- Test PostgreSQL connectivity and credentials
+- Verify S3 endpoint accessibility and credentials
+- Check network connectivity between nodes
+
+### TLS Certificate Issues
+- Ensure PKI alt_names include all required domains
+- Verify certificate paths exist and are readable
+- Check certificate expiration dates
+
+## License
+
+This module is part of the internal infrastructure management system.
\ No newline at end of file
diff --git a/modules/stalwart/examples/hieradata.yaml b/modules/stalwart/examples/hieradata.yaml
new file mode 100644
index 0000000..e8eff84
--- /dev/null
+++ b/modules/stalwart/examples/hieradata.yaml
@@ -0,0 +1,57 @@
+# Example hieradata for profiles::mail::stalwart
+# This shows the required and optional parameters for Stalwart configuration
+
+# Required: Unique node ID for each server in the cluster (1, 2, 3, etc.)
+profiles::mail::stalwart::node_id: 1
+
+# Required: Cluster role name for query_nodes() discovery
+profiles::mail::stalwart::cluster_role: 'mail-backend'
+
+# Required: PostgreSQL connection settings
+profiles::mail::stalwart::postgresql_host: 'pgsql.example.com'
+profiles::mail::stalwart::postgresql_port: 5432
+profiles::mail::stalwart::postgresql_database: 'stalwart'
+profiles::mail::stalwart::postgresql_user: 'stalwart'
+profiles::mail::stalwart::postgresql_password: >
+  ENC[PKCS7,MIIBiQYJKoZIhvcNAQcDoIIBejCCAXYCAQAxggEhMIIBHQIBADAFMAACAQEwDQYJKoZIhvcNAQEBBQAEggEAxample...]
+profiles::mail::stalwart::postgresql_ssl: true
+
+# Required: S3/Ceph-RGW connection settings
+profiles::mail::stalwart::s3_endpoint: 'https://ceph-rgw.example.com'
+profiles::mail::stalwart::s3_bucket: 'stalwart-blobs'
+profiles::mail::stalwart::s3_region: 'default'
+profiles::mail::stalwart::s3_access_key: 'stalwart_access_key'
+profiles::mail::stalwart::s3_secret_key: >
+  ENC[PKCS7,MIIBiQYJKoZIhvcNAQcDoIIBejCCAXYCAQAxggEhMIIBHQIBADAFMAACAQEwDQYJKoZIhvcNAQEBBQAEggEAxample...]
+profiles::mail::stalwart::s3_key_prefix: 'stalwart/'
+
+# Required: Domains this mail backend serves
+profiles::mail::stalwart::domains:
+  - 'example.com'
+  - 'mail.example.com'
+
+# Required: Postfix relay host for SMTP delivery
+profiles::mail::stalwart::postfix_relay_host: 'postfix.example.com'
+
+# Optional: Protocol configuration (defaults shown)
+profiles::mail::stalwart::enable_imap: true
+profiles::mail::stalwart::enable_imap_tls: true
+profiles::mail::stalwart::enable_http: true
+profiles::mail::stalwart::enable_smtp_relay: true
+
+# Optional: Management settings
+profiles::mail::stalwart::manage_dns_records: true
+profiles::mail::stalwart::log_level: 'info'
+
+# Optional: TLS certificate paths (defaults shown)
+profiles::mail::stalwart::tls_cert: '/etc/pki/tls/vault/certificate.crt'
+profiles::mail::stalwart::tls_key: '/etc/pki/tls/vault/private.key'
+
+# Example PKI alt_names configuration for TLS certificates
+# This should include all domains and hostnames that need certificates
+profiles::pki::vault::alt_names:
+  mail-backend:
+    - 'imap.example.com'
+    - 'mail.example.com'
+    - 'autoconfig.example.com'
+    - 'autodiscover.example.com'
diff --git a/modules/stalwart/examples/role-hieradata.yaml b/modules/stalwart/examples/role-hieradata.yaml
new file mode 100644
index 0000000..5679bdb
--- /dev/null
+++ b/modules/stalwart/examples/role-hieradata.yaml
@@ -0,0 +1,58 @@
+# Example hieradata for roles::infra::mail::backend
+# Place this in: hieradata/roles/infra/mail/backend.yaml
+
+# Stalwart module configuration - all parameters passed directly to the module
+# stalwart::node_id: 1234  # Optional - automatically extracted from last 4 digits of hostname
+stalwart::cluster_role: 'mail-backend'
+
+# PostgreSQL connection settings
+stalwart::postgresql_host: 'pgsql.example.com'
+stalwart::postgresql_port: 5432
+stalwart::postgresql_database: 'stalwart'
+stalwart::postgresql_user: 'stalwart'
+stalwart::postgresql_password: >
+  ENC[PKCS7,MIIBiQYJKoZIhvcNAQcDoIIBejCCAXYCAQAxggEhMIIBHQIBADAFMAACAQEwDQYJKoZIhvcNAQEBBQAEggEAxample...]
+stalwart::postgresql_ssl: true
+
+# S3/Ceph-RGW connection settings
+stalwart::s3_endpoint: 'https://ceph-rgw.example.com'
+stalwart::s3_bucket: 'stalwart-blobs'
+stalwart::s3_region: 'default'
+stalwart::s3_access_key: 'stalwart_access_key'
+stalwart::s3_secret_key: >
+  ENC[PKCS7,MIIBiQYJKoZIhvcNAQcDoIIBejCCAXYCAQAxggEhMIIBHQIBADAFMAACAQEwDQYJKoZIhvcNAQEBBQAEggEAxample...]
+stalwart::s3_key_prefix: 'stalwart/'
+
+# Domains this mail backend serves
+stalwart::domains:
+  - 'example.com'
+  - 'mail.example.com'
+
+# Postfix relay host for SMTP delivery
+stalwart::postfix_relay_host: 'postfix.example.com'
+
+# Optional protocol configuration (defaults shown)
+stalwart::enable_imap: true
+stalwart::enable_imap_tls: true
+stalwart::enable_http: true
+stalwart::enable_smtp_relay: true
+
+# Optional management settings
+stalwart::manage_dns_records: true
+stalwart::log_level: 'info'
+
+# Optional TLS certificate paths (defaults work with profiles::pki::vault)
+# stalwart::tls_cert: '/etc/pki/tls/vault/certificate.crt'
+# stalwart::tls_key: '/etc/pki/tls/vault/private.key'
+
+# Optional path overrides (RPM package sets up these defaults)
+# stalwart::config_dir: '/opt/stalwart/etc'
+# stalwart::data_dir: '/var/lib/stalwart'
+
+# PKI alt_names configuration for TLS certificates
+# This should include all domains and hostnames that need certificates
+profiles::pki::vault::alt_names:
+  - 'imap.example.com'
+  - 'mail.example.com'
+  - 'autoconfig.example.com'
+  - 'autodiscover.example.com'
diff --git a/modules/stalwart/manifests/config.pp b/modules/stalwart/manifests/config.pp
new file mode 100644
index 0000000..66b185e
--- /dev/null
+++ b/modules/stalwart/manifests/config.pp
@@ -0,0 +1,32 @@
+# @summary Manages Stalwart Mail Server configuration
+#
+# @api private
+class stalwart::config {
+  assert_private()
+
+  # Main configuration file
+  file { "${stalwart::config_dir}/config.toml":
+    ensure  => file,
+    owner   => 'stalwart',
+    group   => 'stalwart',
+    mode    => '0640',
+    content => template('stalwart/config.toml.erb'),
+    notify  => Service['stalwart'],
+  }
+
+  # Create directories for storage
+  file { "${stalwart::data_dir}/queue":
+    ensure => directory,
+    owner  => 'stalwart',
+    group  => 'stalwart',
+    mode   => '0750',
+  }
+
+  file { "${stalwart::data_dir}/reports":
+    ensure => directory,
+    owner  => 'stalwart',
+    group  => 'stalwart',
+    mode   => '0750',
+  }
+
+}
\ No newline at end of file
diff --git a/modules/stalwart/manifests/dns.pp b/modules/stalwart/manifests/dns.pp
new file mode 100644
index 0000000..fb30150
--- /dev/null
+++ b/modules/stalwart/manifests/dns.pp
@@ -0,0 +1,67 @@
+# @summary Manages DNS autodiscovery records for Stalwart
+#
+# @param target_host
+#   FQDN to point DNS records to (defaults to current server)
+#
+# @api private
+class stalwart::dns (
+  Stdlib::Fqdn $target_host = $facts['networking']['fqdn'],
+) {
+  assert_private()
+
+  # Create autodiscovery DNS records for each domain
+  $stalwart::domains.each |$domain| {
+
+    # Autoconfig record for Thunderbird/Mozilla clients
+    profiles::dns::record { "autoconfig_${domain}":
+      record => "autoconfig.${domain}",
+      type   => 'CNAME',
+      value  => "${target_host}.",
+      zone   => $domain,
+      order  => 100,
+    }
+
+    # Autodiscover record for Outlook/Microsoft clients
+    profiles::dns::record { "autodiscover_${domain}":
+      record => "autodiscover.${domain}",
+      type   => 'CNAME',
+      value  => "${target_host}.",
+      zone   => $domain,
+      order  => 101,
+    }
+
+    # IMAP SRV records
+    profiles::dns::record { "imap_srv_${domain}":
+      record => "_imap._tcp.${domain}",
+      type   => 'SRV',
+      value  => "10 1 143 ${target_host}.",
+      zone   => $domain,
+      order  => 102,
+    }
+
+    profiles::dns::record { "imaps_srv_${domain}":
+      record => "_imaps._tcp.${domain}",
+      type   => 'SRV',
+      value  => "10 1 993 ${target_host}.",
+      zone   => $domain,
+      order  => 103,
+    }
+
+    # CalDAV and CardDAV SRV records
+    profiles::dns::record { "caldav_srv_${domain}":
+      record => "_caldav._tcp.${domain}",
+      type   => 'SRV',
+      value  => "10 1 443 ${target_host}.",
+      zone   => $domain,
+      order  => 104,
+    }
+
+    profiles::dns::record { "carddav_srv_${domain}":
+      record => "_carddav._tcp.${domain}",
+      type   => 'SRV',
+      value  => "10 1 443 ${target_host}.",
+      zone   => $domain,
+      order  => 105,
+    }
+  }
+}
diff --git a/modules/stalwart/manifests/init.pp b/modules/stalwart/manifests/init.pp
new file mode 100644
index 0000000..508d0b7
--- /dev/null
+++ b/modules/stalwart/manifests/init.pp
@@ -0,0 +1,219 @@
+# @summary Main class for managing Stalwart Mail Server
+#
+# This class provides a comprehensive setup of Stalwart Mail Server with
+# clustering, authentication, storage, and protocol support.
+#
+# @example Basic Stalwart setup
+#   class { 'stalwart':
+#     node_id                => 1,
+#     postgresql_host        => 'pgsql.example.com',
+#     postgresql_database    => 'stalwart',
+#     postgresql_user        => 'stalwart',
+#     postgresql_password    => Sensitive('secretpassword'),
+#     s3_endpoint            => 'https://ceph-rgw.example.com',
+#     s3_bucket              => 'stalwart-blobs',
+#     s3_access_key          => 'accesskey',
+#     s3_secret_key          => Sensitive('secretkey'),
+#     domains                => ['example.com'],
+#     postfix_relay_host     => 'postfix.example.com',
+#   }
+#
+# @param node_id
+#   Unique identifier for this node in the cluster (1-N). If not specified,
+#   automatically calculated based on sorted position in cluster member list.
+#
+# @param cluster_role
+#   Role name for cluster member discovery via query_nodes()
+#
+#
+# @param postgresql_host
+#   PostgreSQL server hostname/IP
+#
+# @param postgresql_port
+#   PostgreSQL server port
+#
+# @param postgresql_database
+#   PostgreSQL database name
+#
+# @param postgresql_user
+#   PostgreSQL username
+#
+# @param postgresql_password
+#   PostgreSQL password (Sensitive)
+#
+# @param postgresql_ssl
+#   Enable SSL/TLS for PostgreSQL connections
+#
+# @param s3_endpoint
+#   S3/Ceph-RGW endpoint URL
+#
+# @param s3_bucket
+#   S3 bucket name for blob storage
+#
+# @param s3_region
+#   S3 region
+#
+# @param s3_access_key
+#   S3 access key
+#
+# @param s3_secret_key
+#   S3 secret key (Sensitive)
+#
+# @param s3_key_prefix
+#   S3 key prefix for stalwart objects
+#
+# @param domains
+#   Array of domains this server handles
+#
+# @param postfix_relay_host
+#   Postfix relay host for SMTP delivery
+#
+# @param bind_address
+#   IP address to bind services to
+#
+# @param advertise_address
+#   IP address to advertise to cluster members
+#
+# @param enable_imap
+#   Enable IMAP protocol listener
+#
+# @param enable_imap_tls
+#   Enable IMAP over TLS listener
+#
+# @param enable_http
+#   Enable HTTP listener for JMAP/WebDAV/Autodiscovery
+#
+# @param enable_smtp_relay
+#   Enable SMTP for postfix relay communication
+#
+# @param package_ensure
+#   Package version to install
+#
+# @param config_dir
+#   Stalwart configuration directory
+#
+# @param data_dir
+#   Stalwart data directory
+#
+# @param log_level
+#   Logging verbosity level
+#
+# @param manage_firewall
+#   Whether to manage firewall rules
+#
+# @param tls_cert
+#   Path to TLS certificate file
+#
+# @param tls_key
+#   Path to TLS private key file
+#
+# @param manage_dns_records
+#   Whether to create DNS autodiscovery records
+#
+class stalwart (
+  String                    $cluster_role,
+  Stdlib::Host              $postgresql_host,
+  String                    $postgresql_database,
+  String                    $postgresql_user,
+  Sensitive[String]         $postgresql_password,
+  Stdlib::HTTPUrl           $s3_endpoint,
+  String                    $s3_bucket,
+  String                    $s3_access_key,
+  Sensitive[String]         $s3_secret_key,
+  Array[Stdlib::Fqdn]       $domains,
+  Stdlib::Host              $postfix_relay_host,
+  Optional[Integer]         $node_id                 = undef,
+  Stdlib::Port              $postgresql_port          = 5432,
+  Boolean                   $postgresql_ssl           = true,
+  String                    $s3_region               = 'us-east-1',
+  String                    $s3_key_prefix           = 'stalwart/',
+  Stdlib::IP::Address       $bind_address            = $facts['networking']['ip'],
+  Stdlib::IP::Address       $advertise_address       = $facts['networking']['ip'],
+  Boolean                   $enable_imap             = true,
+  Boolean                   $enable_imap_tls         = true,
+  Boolean                   $enable_http             = true,
+  Boolean                   $enable_smtp_relay       = true,
+  String                    $package_ensure          = 'present',
+  Stdlib::Absolutepath      $config_dir              = '/opt/stalwart/etc',
+  Stdlib::Absolutepath      $data_dir                = '/var/lib/stalwart',
+  Enum['error','warn','info','debug','trace'] $log_level = 'info',
+  Boolean                   $manage_firewall         = false,
+  Stdlib::Absolutepath      $tls_cert                = '/etc/pki/tls/vault/certificate.crt',
+  Stdlib::Absolutepath      $tls_key                 = '/etc/pki/tls/vault/private.key',
+  Boolean                   $manage_dns_records      = true,
+  Optional[Stdlib::Fqdn]    $loadbalancer_host       = undef,
+) {
+
+  # Query cluster members for validation
+  $cluster_query = "enc_role='${cluster_role}' and country='${facts['country']}' and region='${facts['region']}'"
+  $cluster_members = query_nodes($cluster_query, 'networking.fqdn')
+  $sorted_cluster_members = sort($cluster_members)
+
+  # Calculate node_id from last 4 digits of hostname if not provided
+  $my_fqdn = $facts['networking']['fqdn']
+  $hostname = $facts['networking']['hostname']
+
+  # Extract last 4 digits from hostname (e.g., ausyd1nxvm1234 -> 1234)
+  if $hostname =~ /^.*(\d{4})$/ {
+    $hostname_digits = $1
+    $calculated_node_id = Integer($hostname_digits)
+  } else {
+    fail("Unable to extract 4-digit node ID from hostname '${hostname}'. Hostname must end with 4 digits or specify node_id manually.")
+  }
+
+  # Use provided node_id or calculated one
+  $effective_node_id = $node_id ? {
+    undef   => $calculated_node_id,
+    default => $node_id,
+  }
+
+  # Validate parameters
+  if $effective_node_id < 1 {
+    fail('node_id must be a positive integer')
+  }
+
+  if empty($domains) {
+    fail('At least one domain must be specified')
+  }
+
+  if !($my_fqdn in $sorted_cluster_members) {
+    fail("This node (${my_fqdn}) is not found in cluster members for role '${cluster_role}' in ${facts['country']}-${facts['region']}")
+  }
+
+  # Create base directories (user/group/base dirs created by package)
+  file { [$config_dir, $data_dir]:
+    ensure => directory,
+    owner  => 'stalwart',
+    group  => 'stalwart',
+    mode   => '0750',
+  }
+
+  # Include sub-classes in dependency order
+  include stalwart::install
+  include stalwart::config
+  include stalwart::service
+
+  # Handle DNS records if requested
+  if $manage_dns_records {
+    if $loadbalancer_host {
+      # Only first node in cluster creates DNS records pointing to load balancer
+      if $my_fqdn == $sorted_cluster_members[0] {
+        class { 'stalwart::dns':
+          target_host => $loadbalancer_host,
+        }
+      }
+    } else {
+      # Current behavior: each server creates its own DNS records
+      include stalwart::dns
+    }
+  }
+
+  # Class ordering
+  Class['stalwart::install']
+  -> Class['stalwart::config']
+  -> Class['stalwart::service']
+
+  if $manage_dns_records {
+    Class['stalwart::service'] -> Class['stalwart::dns']
+  }
+}
\ No newline at end of file
diff --git a/modules/stalwart/manifests/install.pp b/modules/stalwart/manifests/install.pp
new file mode 100644
index 0000000..7650f77
--- /dev/null
+++ b/modules/stalwart/manifests/install.pp
@@ -0,0 +1,11 @@
+# @summary Manages Stalwart Mail Server package installation
+#
+# @api private
+class stalwart::install {
+  assert_private()
+
+  # Install stalwart package (user/group created by package preinstall script)
+  package { 'stalwart':
+    ensure => $stalwart::package_ensure,
+  }
+}
\ No newline at end of file
diff --git a/modules/stalwart/manifests/service.pp b/modules/stalwart/manifests/service.pp
new file mode 100644
index 0000000..82ff537
--- /dev/null
+++ b/modules/stalwart/manifests/service.pp
@@ -0,0 +1,26 @@
+# @summary Manages Stalwart Mail Server service
+#
+# @api private
+class stalwart::service {
+  assert_private()
+
+  # Service is installed by the RPM package
+  service { 'stalwart':
+    ensure    => running,
+    enable    => true,
+    subscribe => [
+      File[$stalwart::tls_cert],
+      File[$stalwart::tls_key],
+    ],
+  }
+
+  # Add capability to bind to privileged ports (143, 443, 993)
+  systemd::manage_dropin { 'bind-capabilities.conf':
+    ensure        => present,
+    unit          => 'stalwart.service',
+    service_entry => {
+      'AmbientCapabilities' => 'CAP_NET_BIND_SERVICE',
+    },
+    notify        => Service['stalwart'],
+  }
+}
\ No newline at end of file
diff --git a/modules/stalwart/templates/config.toml.erb b/modules/stalwart/templates/config.toml.erb
new file mode 100644
index 0000000..39d3ffe
--- /dev/null
+++ b/modules/stalwart/templates/config.toml.erb
@@ -0,0 +1,257 @@
+# Stalwart Mail Server Configuration
+# Generated by Puppet - DO NOT EDIT MANUALLY
+
+[server]
+hostname = "<%= @facts['networking']['fqdn'] %>"
+greeting = "Stalwart ESMTP"
+
+[server.listener."smtp-relay"]
+bind = ["<%= @bind_address %>:25"]
+protocol = "smtp"
+greeting = "Stalwart SMTP Relay"
+
+<% if @enable_imap -%>
+[server.listener."imap"]
+bind = ["<%= @bind_address %>:143"]
+protocol = "imap"
+<% end -%>
+
+<% if @enable_imap_tls -%>
+[server.listener."imaps"]
+bind = ["<%= @bind_address %>:993"]
+protocol = "imap"
+tls.implicit = true
+<% end -%>
+
+<% if @enable_http -%>
+[server.listener."https"]
+bind = ["<%= @bind_address %>:443"]
+protocol = "http"
+tls.implicit = true
+<% end -%>
+
+[server.tls]
+enable = true
+implicit = false
+certificate = "default"
+
+# Cluster Configuration
+<% other_cluster_members = @sorted_cluster_members.reject { |member| member == @facts['networking']['fqdn'] } -%>
+<% cluster_size = @sorted_cluster_members.length -%>
+[cluster]
+node-id = <%= @effective_node_id %>
+
+<% if cluster_size > 1 -%>
+# Peer-to-peer coordination
+[cluster.coordinator]
+type = "peer-to-peer"
+addr = "<%= @bind_address %>:11200"
+advertise-addr = "<%= @advertise_address %>:11200"
+
+<% other_cluster_members.each do |node| -%>
+[[cluster.coordinator.peers]]
+addr = "<%= node %>:11200"
+<% end -%>
+
+# Cluster roles for 3-node setup
+[cluster.roles.purge]
+stores = ["1", "2", "3"]
+accounts = ["1", "2"]
+
+[cluster.roles.acme]
+renew = ["1"]
+
+[cluster.roles.metrics]
+calculate = ["1", "2"]
+push = ["1"]
+
+[cluster.roles.push-notifications]
+push-notifications = ["1", "3"]
+
+[cluster.roles.fts-indexing]
+fts-indexing = ["2", "3"]
+
+[cluster.roles.bayes-training]
+bayes-training = ["1"]
+
+[cluster.roles.imip-processing]
+imip-processing = ["2"]
+
+[cluster.roles.calendar-alerts]
+calendar-alerts = ["3"]
+<% end -%>
+
+# Storage Configuration
+
+# PostgreSQL store for data, FTS, and in-memory
+[store."postgresql"]
+type = "postgresql"
+host = "<%= @postgresql_host %>"
+port = <%= @postgresql_port %>
+database = "<%= @postgresql_database %>"
+user = "<%= @postgresql_user %>"
+password = "<%= @postgresql_password %>"
+timeout = "15s"
+
+[store."postgresql".tls]
+enable = <%= @postgresql_ssl %>
+allow-invalid-certs = false
+
+[store."postgresql".pool]
+max-connections = 10
+
+[store."postgresql".purge]
+frequency = "0 3 *"
+
+# PostgreSQL directory queries for authentication
+[store."postgresql".query]
+name = "SELECT name, type, secret, description, quota FROM accounts WHERE name = $1 AND active = true"
+members = "SELECT member_of FROM group_members WHERE name = $1"
+recipients = "SELECT name FROM emails WHERE address = $1 ORDER BY name ASC"
+emails = "SELECT address FROM emails WHERE name = $1 ORDER BY type DESC, address ASC"
+
+# S3/Ceph-RGW store for blobs
+[store."s3"]
+type = "s3"
+bucket = "<%= @s3_bucket %>"
+region = "<%= @s3_region %>"
+access-key = "<%= @s3_access_key %>"
+secret-key = "<%= @s3_secret_key %>"
+endpoint = "<%= @s3_endpoint %>"
+timeout = "30s"
+key-prefix = "<%= @s3_key_prefix %>"
+compression = "lz4"
+
+[store."s3".purge]
+frequency = "30 5 *"
+
+# Storage assignment
+[storage]
+data = "postgresql"
+fts = "postgresql"
+blob = "s3"
+lookup = "postgresql"
+in-memory = "postgresql"
+
+# Directory configuration
+[directory."postgresql"]
+type = "sql"
+store = "postgresql"
+
+[directory."postgresql".columns]
+name = "name"
+description = "description"
+secret = "secret"
+email = "address"
+quota = "quota"
+class = "type"
+
+# Authentication configuration
+[authentication]
+fallback-admin = ["admin@<%= @domains.first %>"]
+
+[authentication.directory]
+directories = ["postgresql"]
+
+# Authorization configuration
+[authorization]
+directory = "postgresql"
+
+# JMAP configuration
+[jmap]
+directory = "postgresql"
+
+[jmap.protocol]
+request-max-size = 10485760
+get.max-objects = 500
+query.max-results = 5000
+changes.max-results = 5000
+upload.max-size = 50000000
+upload.ttl = "1h"
+
+# IMAP configuration
+[imap]
+directory = "postgresql"
+
+[imap.protocol]
+max-requests = 64
+
+# SMTP configuration for postfix relay
+[session.rcpt]
+relay = true
+
+[session.data]
+pipe.command = "sendmail"
+pipe.arguments = ["-i", "-f", "{sender}", "{recipient}"]
+
+# Outbound SMTP configuration
+[queue]
+path = "<%= @data_dir %>/queue"
+
+[queue.schedule]
+retry = ["2s", "5s", "1m", "5m", "15m", "30m", "1h", "2h"]
+notify = ["1d", "3d"]
+expire = "5d"
+
+[session.extensions]
+future-release = "7d"
+
+# Relay configuration for postfix
+[remote."postfix"]
+address = "<%= @postfix_relay_host %>"
+port = 25
+protocol = "smtp"
+
+[session.mail]
+rewrite = [
+  { if = "!is_local_domain(rcpt_domain)", then = "set('remote', 'postfix')" }
+]
+
+# HTTP configuration
+[server.http]
+use-x-forwarded = false
+permissive-cors = false
+
+# Disable spam filtering (handled by postfix)
+[session.ehlo]
+reject-non-fqdn = false
+
+[session.mail]
+rewrite = []
+
+[session.rcpt]
+directory = "postgresql"
+relay = true
+max-recipients = 25
+
+[session.data]
+max-messages = 10
+max-message-size = 52428800
+
+# TLS configuration
+[certificate."default"]
+cert = "%{file:<%= @tls_cert %>}%"
+private-key = "%{file:<%= @tls_key %>}%"
+
+# Logging configuration
+[tracer]
+type = "log"
+level = "<%= @log_level %>"
+ansi = false
+multiline = true
+
+[tracer.file]
+path = "/var/log/stalwart/stalwart.log"
+rotate = "daily"
+keep = 30
+
+# Report storage
+[report]
+path = "<%= @data_dir %>/reports"
+hash = "sha256"
+encrypt = false
+
+# Metrics configuration
+[metrics]
+prometheus.enable = true
+prometheus.port = 9090
diff --git a/site/roles/manifests/infra/mail/backend.pp b/site/roles/manifests/infra/mail/backend.pp
index c13b141..a7c64a1 100644
--- a/site/roles/manifests/infra/mail/backend.pp
+++ b/site/roles/manifests/infra/mail/backend.pp
@@ -1,9 +1,14 @@
-# a role to deploy a imap/pop3 backend for mail services
+# roles::infra::mail::backend
+#
+# Configures Stalwart IMAP backend servers in a clustered configuration
+# with PostgreSQL for data/fts/memory storage and S3/Ceph-RGW for blob storage.
+# Integrates with postfix hosts for SMTP relay functionality.
+#
 class roles::infra::mail::backend {
   if $facts['firstrun'] {
     include profiles::defaults
     include profiles::firstrun::init
-  }else{
+  } else {
     include profiles::defaults
     include profiles::base
   }