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Protovalidate is the semantic validation library for Protobuf. It provides standard annotations to validate common rules on messages and fields, as well as the ability to use CEL to write custom rules. It's the next generation of protoc-gen-validate.

With Protovalidate, you can annotate your Protobuf messages with both standard and custom validation rules:

syntax = "proto3";
package acme.user.v1;
import "buf/validate/validate.proto";
message User {
 string id = 1 [(buf.validate.field).string.uuid = true];
 uint32 age = 2 [(buf.validate.field).uint32.lte = 150]; // We can only hope.
 string email = 3 [(buf.validate.field).string.email = true];
 string first_name = 4 [(buf.validate.field).string.max_len = 64];
 string last_name = 5 [(buf.validate.field).string.max_len = 64];
 option (buf.validate.message).cel = {
 id: "first_name_requires_last_name"
 message: "last_name must be present if first_name is present"
 expression: "!has(this.first_name) || has(this.last_name)"
 };
}

To start using Protovalidate in your projects, see the developer quickstart, Protovalidate overview, or go directly to the repository for your language of choice:

• protovalidate-go (Go)
• protovalidate-java (Java)
• protovalidate-python (Python)
• protovalidate-cc (C++)
• protovalidate-es (TypeScript and JavaScript)

Comprehensive documentation for Protovalidate is available at protovalidate.com.

Highlights include:

• The developer quickstart
• Comprehensive RPC quickstarts for Connect and Go, gRPC and Go, gRPC and Java, and gRPC and Python
• A migration guide for protoc-gen-validate users

We genuinely appreciate any help! If you'd like to contribute, check out these resources:

• Contributing Guidelines: Guidelines to make your contribution process straightforward and meaningful
• Conformance testing utilities: Utilities providing acceptance testing of protovalidate implementations

Offered under the Apache 2 license.