Add all ingredients except tapioca starch and hot water to a small saucepan and bring to a simmer.
Cook for 4 minutes maintaining heat level at a simmer.
Mix tapioca starch and hot water in a small bowl, then slowly add to the sweet chili mixture.
Bring to a boil and cook for 1 minute.
Remove saucepan from heat and adjust seasoning, if necessary.
Serve in a ramekin with lumpia shanghai. Store leftover sweet chili sauce in a sterile air-tight container. Keep refrigerated. Sauce is good for 1 week.