Common Expression Language The Common Expression Language (CEL) implements common semantics for expression evaluation, enabling different applications to more easily interoperate. Key Applications Security policy: organization have complex infrastructure and need common tooling to reason about the system as a whole Protocols: expressions are a useful data type and require interoperability across programming languages and platforms. Guiding philosophy: Keep it small & fast. CEL evaluates in linear time, is mutation free, and not Turing-complete. This limitation is a feature of the language design, which allows the implementation to evaluate orders of magnitude faster than equivalently sandboxed JavaScript. Make it extensible. CEL is designed to be embedded in applications, and allows for