rspamd/rspamd

Free

Rapid spam filtering system.

FreeFree tier

Type

Open Source

Visit Website GitHub (38 stars)

About rspamd/rspamd

Rspamd is an advanced spam filtering system and email processing framework that evaluates messages using a combination of rules including regular expressions, statistical analysis, and custom services such as URL blacklists. Each message is analyzed and given a verdict that can be used by an MTA (e.g., Postfix or Sendmail) to reject the message or add spam headers. Rspamd supports DKIM signing, acts as a Milter for direct MTA integration, and is designed to handle hundreds of messages per second. It features a comprehensive Lua API for writing custom rules and plugins, and an asynchronous network API for accessing external resources like DNS, HTTP, or TCP/UDP services. The project is open source under the Apache 2.0 license.

Key Features

Rules evaluation using regular expressions, statistical analysis, and URL blacklists

Provides verdict for MTA processing (reject, header, etc.)

Supports DKIM signatures and message modifications

Milter for direct integration with Postfix and Sendmail

High performance design handling hundreds of messages per second

Comprehensive Lua API for custom rules and plugins

Asynchronous network API for DNS, HTTP, and generic TCP/UDP access

Open source under Apache 2.0 license

Pros & Cons

Pros

Open source and free to use
High throughput, capable of processing hundreds of messages per second
Extensible via Lua API for custom filtering logic
Supports multiple analysis methods (regex, statistics, blacklists)
Direct Milter support for popular MTAs

Best For

Spam filtering for email serversEmail message processing and scoringIntegration with MTA systems like Postfix and Sendmail via Milter

FAQ

What is Rspamd?

Rspamd is an advanced spam filtering system and email processing framework that evaluates messages using rules, statistical analysis, and custom services.

Is Rspamd free?

Yes, Rspamd is open source and distributed under the Apache 2.0 License.

Can Rspamd integrate with Postfix?

Yes, Rspamd can act as a Milter for direct interaction with Postfix and Sendmail.

What programming API does Rspamd offer?

Rspamd provides a comprehensive Lua API for writing custom rules and plugins, as well as an asynchronous network API for accessing external resources.