Integrated assessment models (IAMs) are crucial for climate policymaking, offering climate mitigation scenarios and contributing to IPCC assessments. However, IAMs face criticism for lack of transparency and poor capture of recent technology diffusion and dynamics. We introduce the Potsdam Integrated Assessment Modeling validation tool, <em>piamValidation</em>, an open-source R package for validating IAM scenarios. The <em>piamValidation</em> tool enables systematic comparisons of variables from extensive IAM datasets against historical data and feasibility bounds, or across scenarios and models. This functionality is particularly valuable for harmonizing scenarios across multiple IAMs. Moreover, the tool facilitates the systematic comparison of near-term technology dynamics with external observational data, including historical trends, near-term developments, and stylized facts. We apply the tool to the integrated assessment model REMIND for near-term technology trend validation, demonstrating its potential to enhance transparency and reliability of IAMs.