The entities involved in the development of the QSAR Toolbox project (ECHA, OECD, or LMC) are not considered suppliers. They do not have any contractual agreements with any company nor obligations towards Toolbox users. The Toolbox is developed and provided free of charge under an End User License Agreement (EULA), which every user must accept during the installation process.

Although ECHA, OECD, or LMC do not have any obligations or responsibilities toward Toolbox users, quality assurance remains a crucial aspect of the QSAR Toolbox development. Since this tool is intended for regulatory applications, the transparency, reproducibility, and consistency of the algorithms implemented in the QSAR Toolbox are of paramount importance.

Each publicly released version of the QSAR Toolbox undergoes extensive testing. For that it has been implemented a multi-stage testing strategy. The first stage occurs during the development process to ensure the highest standards and flawless operation. This process begins with unit tests, where individual components of the Toolbox are examined in isolation. Next, integration tests are conducted to ensure these components work together seamlessly, followed by system tests to verify the entire Toolbox system against specified requirements (test scenarios). Finally, user acceptance testing (UAT) is performed, where real users test the Toolbox in a production-like environment to ensure it meets their requirements and expectations. Throughout these phases, various testing methods are used, including manual, automated, and performance testing, to identify and fix bugs, improve performance, and ensure the Toolbox is reliable and user-friendly.

Then at the second stage the OECD experts, who are part of the OECD QSAR Toolbox management group, test the pre-release version of Toolbox for its usability, scientific robustness of newly implemented features and overall consistency. Only after this thorough testing the new version of the Toolbox is publicly released. In addition each release is accompanied by release notes listing all changes and improvements made to the software.

The reproducibility and stability of the tool have also been confirmed by the OECD Working Party of the National Coordinators of Test Guidelines Program (WNT), which concluded that specific Toolbox functionality can be included in the Revised Guidance on Skin Sensitisation.