A blockchain-based inventory system with lot size-dependent lead times and uncertain carbon footprints

•A blockchain-based supply chain in terms of reducing CO2 by investing in green technology.•Lead time for the first delivery consists of production and non-productive time, while the lead time for the rest of the deliveries is only transportation time.•Fuzzify all the carbon factors as an intuitionistic triangular fuzzy number and use a signed distance method for defuzzification.•The results indicate that the blockchain has significant impacts on the optimal decisions and carbon reduction results. Securing visibility and dependable information from stakeholders poses a significant challenge for companies engaged in supply chain management. Timely and accurate information exchange is crucial for assessing factors such as carbon emissions and consumer demand. This paper explores the impact of digital and carbon reduction technologies on supply chain decisions, incorporating fuzzy logic and blockchain technology for enhanced decision-making. We specifically focus on a single buyer ordering from a vendor, where faulty items are promptly returned upon inspection. The lead time for the initial delivery includes both production and non-productive time, while successive deliveries only entail transportation time. The research employs intuitionistic triangular fuzzy numbers to represent all carbon factors and integrates blockchain technology to improve demand forecasting. The purpose is to determine the optimal strategies to minimize the carbon and joint total cost of the system. A solution methodology has been proposed for determining optimal strategies, illustrated through a numerical example. The optimal decisions are compared, both with and without blockchain, to validate the proposed model. The findings suggest that blockchain has a substantial impact on both optimal decision-making and the results of carbon reduction efforts. Sensitivity analysis reveals that a blockchain-based supply chain is both time- and cost-efficient, reduces costs and errors in data information, and efficiently shortens lead time in the network.