Is Sri Lankan street food too spicy for foreigners.

However, the vendors are very friendly and accustomed to tourists. If you order food made fresh on the spot, like hoppers or kottu, you can easily ask them to omit the chili entirely. Just say no spice clearly.

For pre made snacks like samosas or vadai sitting in glass cabinets, you cannot change the spice level. It is best to buy just one to test your tolerance before ordering a whole bag.