Matomo Referrer Spam List

Matomo Referrer Spam List is a community-maintained blocklist of domains known to generate referrer spam, the fake referral traffic that pollutes web analytics reports. Maintained by the Matomo project, it is distributed as a plain text file with one spammer host per line, making it trivial to consume from any language or tool.

Because it is packaged for Composer, PHP projects can install it as a dependency and load the current list programmatically, keeping their referrer filtering up to date as the community adds newly discovered spam domains.

What You Get

• A curated spammers.txt list of known referrer-spam domains, one host per line
• Composer packaging so PHP projects can install and update it as a dependency
• A language-agnostic plain-text format any tool can parse
• An open contribution process for reporting new spam domains
• Ongoing community maintenance keeping the list current

Common Use Cases

• Filtering referrer spam out of web analytics reports
• Excluding known spam domains when attributing referral traffic
• Feeding a denylist into log-processing or analytics pipelines
• Keeping a self-maintained referrer filter in sync with a community source

Under The Hood

Architecture - There is no code to speak of: the deliverable is spammers.txt, a newline-delimited list of hostnames maintained through GitHub pull requests and issue-driven additions. Consumers parse the file into a set and test candidate referrers against it. The repository’s value is the curated data and the review process behind it rather than any runtime logic.

Tech Stack - A plain-text data file distributed via Composer/Packagist, with contribution guidelines in CONTRIBUTING.md. There is no language runtime or dependency; any tool that can read a text file can use it.

Code Quality - As a data list, quality is measured by curation discipline: entries are added via reviewed pull requests, empty lines are tolerated by consumers, and the list stays actively maintained with strong community engagement. It is one of the most widely used referrer-spam sources.

API Design - The interface is a file path. Reading it (for example with PHP’s file() into an array) yields the denylist directly, so integration is a few lines regardless of language.