Apache RAT vs FOSSology

Apache RAT is a free, open-source release-audit tool for checking software distributions, with particular attention to license headers. Version 0.18 provides a command-line client, an Ant task library, and a Maven plugin. You can include or exclude files using patterns, collections, pattern files, and file-size limits; apply approved-license lists; and produce plain, XML, missing-header, or unapproved-license reports. The Maven plugin can write target/rat.txt or add a report to a generated site. RAT can add Apache-2.0 headers and copyright notices to files allowed by configuration. XML license definitions are supported, and experienced users can extend matchers, formats, reports, and interfaces. It runs on Linux and is intended for self-hosted, on-premise use. Building requires Java 17, with Maven 3.9.13 or later recommended. Reports need interpretation and project-specific tuning, and heuristics can miss issues.

FOSSology is an open-source system for examining software for license, copyright, and export-control information. Upload individual files or packages, then unpack and scan them with selected agents. Nomos looks for license indicators through phrases, regular expressions, and heuristics; Monk checks text against stored license texts or phrases supplied by users. Its web interface supports review of findings, license-text management, bulk recognition, aggregated file views, and reusing reviews for files with matching hashes. It can identify copyright statements and presents keyword-based findings that users can review for possible export-control relevance. Reports include SPDX 2.0 exports, Debian copyright files, hierarchical file lists with license identifiers, and Readme files with identified license and copyright details. A REST API supports CI/CD use, uploads, and scan triggers from other applications; the command line can retrieve SPDX files. Deployment options include Docker, Vagrant with VirtualBox, or source installation. It is free, with on-premise deployment options. One stated limit: it cannot determine which libraries produced a binary; binary analysis tools are needed for that task.