Does the integration of finance and technology bring policy dividends for low-carbon development? Quasi-experimental evidence from China

Financial technology (FinTech) has emerged as a key policy instrument for transforming economic development models. Whether it can energize the low-carbon economy and enhance carbon emission efficiency (CEE) has drawn increasing scholarly attention. Using panel data from 278 Chinese cities (2006–2021), this study constructs a quasi-natural experiment and applies a difference-in-differences (DID) model to evaluate the policy effects of FinTech on CEE. Mediation and moderation models further explore the mechanisms underlying this relationship. The findings reveal that FinTech significantly improves CEE, generating policy dividends that advance low-carbon development. This conclusion remains robust under dual machine learning causal inference, propensity score matching DID, and other robustness tests. Financing constraints, innovation level, and industrial structure upgrading fully mediate the effect of FinTech on CEE, where financing constraints and innovation show positive mediation effects, while industrial structure upgrading has a negative one. Moreover, financial agglomeration weakens FinTech’s positive influence on CEE, and the effects differ across regions, development levels, and resource endowments. This study broadens the analytical framework connecting FinTech and CEE and deepens understanding of the mechanisms linking financial innovation to low-carbon transition.