Common Expression Language The Common Expression Language (CEL) is a non-Turing complete language designed for simplicity, speed, safety, and portability. CEL's C-like syntax looks nearly identical to equivalent expressions in C++, Go, Java, and TypeScript. // Check whether a resource name starts with a group name. resource.name.startsWith("/groups/" + auth.claims.group) // Determine whether the request is in the permitted time window. request.time - resource.age duration("24h") // Check whether all resource names in a list match a given filter. auth.claims.email_verified && resources.all(r, r.startsWith(auth.claims.email)) A CEL "program" is a single expression. The examples have been tagged as