The original Huy Fong Srichacha sauce is vegan.
Here are its ingredients:
INGREDIENTS: Chili, sugar, garlic, salt, distilled vinegar, potassium sorbate, sodium bisulfite, and xanthan gum
All of those are clearly vegan ingredients.
However, if you’re buying a “srichacha” sauce that is made by a different company, it may not be vegan.
These sauces often have similar, but different ingredients. Common non-vegan additions are fish sauce and shrimp paste.
So either make sure you get the original Huy Fong srichacha, or carefully check the ingredients of any close alternatives before buying.