Common Expression Language (CEL) is a lightweight, high-performance expression language designed to be embedded within applications. All of Protovalidate's standard rules are written in CEL, and it's how Protovalidate allows you to write your own custom or predefined rules.
Learn more about using CEL in Protovalidate's documentation:
- Write custom rules for messages or fields.
- Create reusable predefined rules.
- Explore the reference documentation for Protovalidate's CEL extensions.
- See the inner workings of how CEL and Protovalidate work together.
Protovalidate CEL expressions can use the entire CEL standard library, including:
- CEL's standard functions, as detailed in the list of standard definitions
- CEL's standard macros
- CEL's extended string function library