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)"
  };
}

Once you've added @bufbuild/protovalidate to your project, validation is simple:

import { create } from "@bufbuild/protobuf";
import { createValidator } from "@bufbuild/protovalidate";
import { MoneyTransferSchema } from "./gen/banking_pb";

const transfer = create(MoneyTransferSchema);

const validator = createValidator();
const result = validator.validate(MoneyTransferSchema, transfer);
if (result.kind !== "valid") {
  // Handle failure.
}

const validator = createValidator({
  regexMatch: (pattern: string, against: string): boolean => new RE2(pattern).test(against),
});

• @bufbuild/protovalidate: Validates Protobuf messages at runtime based on user-defined validation rules.

Note that protovalidate-es requires the Protobuf runtime @bufbuild/protobuf.

Protovalidate isn't just for ECMAScript! You might be interested in sibling repositories for other languages:

• protovalidate-go (Go)
• protovalidate-java (Java)
• protovalidate-python (Python)
• protovalidate-cc (C++)

Additionally, protovalidate's core repository provides:

• Protovalidate's Protobuf API
• Example .proto files using protovalidate
• Conformance testing utilities for acceptance testing of protovalidate implementations

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
• Protovalidate-ES conformance executor: Conformance testing executor

Offered under the Apache 2 license.