After 15 years running XMPP infrastructure, I've narrowed down the most robust server options that meet professional deployment requirements:

# Quick test for server compatibility
xmpp_servers = ["ejabberd", "Prosody", "Openfire", "Tigase"]
requirements = ["Linux support", "Clustering", "BOSH", "WebSocket"]

Written in Erlang, ejabberd handles massive scale with ease. Key advantages:

• Native support for 50K+ concurrent connections per node
• Built-in Mnesia database (PostgreSQL/MySQL optional)
• Modular architecture with 200+ available modules

# Sample ejabberd.yml configuration
listen:
  -
    port: 5222
    module: ejabberd_c2s
    max_stanza_size: 65536
  -
    port: 5280
    module: ejabberd_http
    request_handlers:
      "/ws": ejabberd_http_ws

Perfect for smaller deployments with Lua's flexibility:

-- Example Prosody plugin in Lua
local mod_muc = module:require("muc");
module:hook("muc-occupant-joined", function(event)
    local stanza = event.stanza;
    mod_muc.broadcast_message(event.room, "Welcome "..event.occupant.nick.."!");
end);

Feature	ejabberd	Prosody	Tigase
XEP-0357 (Push)	✓	✓	✓
XEP-0363 (HTTP Upload)	✓	✓	✓
Database Sharding	✓	✗	✓

For high-availability setups, I recommend containerized deployment:

# Docker compose snippet for ejabberd cluster
version: '3'
services:
  ejabberd1:
    image: ejabberd/ecs
    environment:
      - ERLANG_NODE_ARG=ejabberd@node1
      - CLUSTER_NODES=ejabberd@node1 ejabberd@node2
    ports:
      - "5222:5222"

Always implement these measures for production servers:

# TLS configuration best practices
c2s_require_encryption: true
s2s_require_encryption: true
s2s_secure_auth: true
certfiles:
  - "/etc/letsencrypt/live/xmpp.example.com/fullchain.pem"

For modern web compatibility, ensure WebSocket and BOSH support are properly configured alongside traditional TCP connections.

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When choosing an XMPP (Jabber) server for Linux, developers need to balance features, stability, and extensibility. Here's a technical breakdown of the best options available today.

Key factors for professional deployment:

• Protocol compliance (XMPP RFCs and XEPs)
• Scalability architecture
• Authentication backends (LDAP, SQL, etc.)
• Modular extension system
• Cluster support

1. Ejabberd

The most battle-tested option, written in Erlang:

# Sample ejabberd.yml configuration
listen:
  -
    port: 5222
    module: ejabberd_c2s
    max_stanza_size: 65536
    shaper: c2s_shaper
    access: c2s

Pros:

• Horizontal scaling out of the box
• Native MQTT support
• Excellent documentation

2. Prosody

Lightweight Lua-based server ideal for smaller deployments:

-- Basic Prosody config
VirtualHost "example.com"
    enabled = true
    ssl = {
        key = "/path/to/key.pem";
        certificate = "/path/to/cert.pem";
    }

Unique features:

• Low memory footprint
• Dynamic module loading
• Best-in-class BOSH support

3. Openfire

Java-based with excellent admin UI:

<provider>
    <class>org.example.CustomAuthProvider</class>
    <name>customAuth</name>
</provider>

Feature	Ejabberd	Prosody	Openfire
MAM (XEP-0313)	✅	✅	✅
WebSocket	✅	✅	❌
IoT Protocols	✅	❌	❌

For high-availability setups, Ejabberd's clustering capabilities are unmatched. Here's a basic cluster setup:

# On node1
ejabberdctl join_cluster node2@hostname

# Verify
ejabberdctl list_cluster

All major servers support custom modules. Example Prosody module skeleton:

local mod = {}

function mod.load()
    -- Initialization code
end

return mod

Essential metrics to track:

# Ejabberd stats example
ejabberdctl connected_users_number
ejabberdctl incoming_s2s_number

For production environments, consider integrating with Prometheus or similar monitoring systems.

For most enterprise use cases, Ejabberd provides the most complete solution. Smaller teams may prefer Prosody's simplicity, while organizations needing turnkey solutions might choose Openfire.