Demand for contactless payments and e-commerce has grown in South Korea during the COVID-19 pandemic. This is good news for payment service operators, but the market is very fragmented, so adding payment options is a time-consuming process for many merchants. CHAI wants to fix this with an API that enables companies to accept over 20 payment systems. The Seoul-based startup announced today it has raised a $60 million Series B. The round was led by Hanhwa Investment & Securities, with participation from SoftBank Ventures Asia (the early-stage venture capital arm…