They’re not exactly the same, though they are similar. Both use tapioca starch, which gives these toppings their signature chewy and bouncy textures. However, sago are a lot smaller than the more common boba you see in pearl milk tea shops, so they cook faster. Cooked sago ends up translucent, whereas boba tends to be brown from either food coloring and/or the usage of brown sugar in the pearls (see this milk tea ice cream topped with brown sugar boba!). Sago is also typically not sweetened or mixed with anything before being added to a drink or dessert. Comparatively, boba is typically sweetened with honey or brown sugar to season.