Increasing climate emergency and environmental degradation have fast-tracked the necessity of financial instruments that are sustainable and promote economic growth in accordance with the responsibility towards the environment. A new area between the business of finance and the field of sustainability, called Green Fintech, provides new avenues to direct investments towards environmentally conscious projects and make financial markets become more efficient, transparent, and accessible. The current paper focuses on the review of sustainable investment products and their design and deployment with the help of digital technologies including artificial intelligence, blockchain, big data analytics, and mobile platforms. It puts greater emphasis on the opportunities Green Fintech can offer to track environmental impact in real time, seal green bonds and buy and sell carbon credits, as well as encouraging renewable energy and climate-smart financing to be inclusive. In addition, the paper examines the role played by regulatory regimes, investors savvy and digital illiteracy on the implementation of Green Fintech solutions in international markets. Using case studies, industry practices, and overview of the topic, the research highlights the prospects and challenges of integrating sustainability to the fintech ecosystem, such as the problem of greenwashing, data integrity, and scalability. Our results indicate that the Green Fintech should contribute to the reallocation of capitals in low-carbon economies besides democratizing access to sustainable investment opportunities of both retail and institutional investors. Finally, the paper posits that Green Fintech can become an indispensable facilitator of the global shift towards the more robust and inclusive financial system as long as the stakeholders can and will cooperate to achieve transparency, accountability, and regulatory consistency.