InspIRCd

InspIRCd is a high‑performance, modular Internet Relay Chat (IRC) server written in modern C++. It targets UNIX‑like systems and Windows, providing a lightweight core that exposes its full feature set through an extensible module framework. The design philosophy is to keep the base daemon minimal—ensuring stability and security—while allowing advanced functionality (TLS, SASL, channel modes, etc.) to be added on demand. This makes it attractive for developers who need a reliable IRC backbone that can be tailored to specific operational policies without the bloat of monolithic servers.

Key Features & Core Capabilities

• Advanced Module System – Modules are compiled as shared objects (.so/.dll) and loaded at runtime, enabling features such as ssl_openssl, sasl, rline, and custom command handlers. The API exposes hooks for user events, channel operations, and server link management.
• TLS & Security – Built‑in OpenSSL support with configurable security levels (sslprofile:securitylevel), automatic handling of certificate chains, and integration with the Public Suffix List for link data validation.
• SASL & Authentication – Full SASL support via the sasl module, allowing integration with external authentication backends (e.g., PAM, LDAP).
• Scalable Networking – Event‑driven I/O using libuv‑like abstractions, non‑blocking sockets, and an efficient connection pool that scales to thousands of simultaneous clients on commodity hardware.
• Configuration‑Driven – A declarative XML/INI style configuration file (inspircd.conf) drives both core settings and module options, making it straightforward to script deployments.

Architecture & Technical Stack

• Language – C++17/20, leveraging modern constructs (smart pointers, std::variant, concurrent containers) for safety and performance.
• Build System – CMake 3.20+ with optional Conan 2 for dependency resolution on Windows; GNU Make on Linux/BSD.
• Runtime Dependencies – OpenSSL, zlib, and libevent (or similar event loop library). On Windows, the build pulls in pre‑built binaries via Conan.
• Database Interaction – Optional persistence modules (e.g., MySQL, PostgreSQL) can be loaded to store user accounts, channel metadata, and ban lists. The core does not ship a database engine; it relies on external modules for storage.
• Logging & Monitoring – Structured logging to stdout/stderr with log levels; optional integration with syslog or external monitoring via hooks.

Deployment & Infrastructure

• Self‑Hosting – Designed for on‑premises deployment; runs as a system service (systemd, OpenRC, Windows Service). Docker images are maintained in the inspircd-docker repository for quick containerized setups.
• Scalability – Horizontal scaling is achieved by running multiple IRC daemons behind a load balancer or using the link feature to connect servers in a network. Each instance can be configured with distinct user classes and rate limits.
• Resource Footprint – The minimal core consumes <50 MB RAM on a typical Linux server, making it suitable for embedded devices or lightweight VPS instances.
• High Availability – Built‑in support for server link monitoring, automatic failover, and graceful shutdown hooks. The module system allows custom health‑check modules to report metrics to Prometheus or other monitoring stacks.

Integration & Extensibility

• Plugin API – Exposes a rich C++ API for module authors: event callbacks, command registration, hook insertion, and data store access. The SDK is documented in the official docs site (docs.inspircd.org) with sample modules.
• Webhooks & External Hooks – Modules can emit JSON events to HTTP endpoints, enabling integration with chatops platforms (e.g., Mattermost, Slack) or custom dashboards.
• Customization – The configuration file supports user classes, connect classes, and channel modes that can be fine‑tuned per network. Admins can write custom scripts in Lua (via the lua module) to extend behavior without recompiling.
• Community & Support – Active IRC channels (#inspircd and #inspircd.dev) provide real‑time assistance. The project’s GitHub issues tracker and mailing list are used for feature requests, security patches, and release coordination.

Use Cases

• Enterprise Internal Chat – Deploy a secure IRC backbone for internal communication, leveraging SASL authentication and fine‑grained channel permissions.
• Open Source Projects – Host a public testnet or community network with minimal overhead, using Docker for quick rollouts and rollback.
• Educational Environments – Provide a hands‑on IRC server for networking courses, where students can experiment with module development and network security.
• Embedded Systems – Run a lightweight IRC client/server on IoT devices for remote telemetry or control, thanks to the low resource usage.

Advantages Over Alternatives