# Protovalidate

Protocol Buffer Validation - Go, Java, Python, C++ and JS/TS

Repository: https://github.com/bufbuild/protovalidate
Canonical: https://ross.abutalabs.com/products/protovalidate
Homepage: https://protovalidate.com
Language: Go
License: Apache-2.0
License Family: permissive
Topics: cel, common-expression-language, protobuf, protocol-buffers, validation, cc, cpp, golang, java, ecmascript, javascript, typescript
Last push: 2026-08-25T20:59:50+00:00
Link (homepage): https://protovalidate.com
Link (site_page): https://protovalidate.com/about
Link (site_page): https://protovalidate.com/quickstart-go
Link (site_page): https://protovalidate.com/quickstart-es
Link (site_page): https://protovalidate.com/quickstart-java

## Health v2 (maintenance only)
Score: 94/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 92, longevity 85
- inputs: {"age_days": 1196, "days_push": 8, "days_rel": 55, "gap_med": 4.5, "n_releases_24m": 35}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1552, forks 65 (observed 2026-08-28T04:05:02.349691+00:00)

## What it is
Protovalidate is a semantic validation library for Protocol Buffers that lets developers define validation rules (standard constraints plus CEL expressions) directly in proto schemas, enforced consistently across Go, JavaScript/TypeScript, Java, Python, and C++. It is the successor to protoc-gen-validate (PGV), which is now in maintenance mode.

## Use cases
- validate protobuf message fields like email, uuid, and length constraints
- enforce semantic data rules in proto schemas across multiple languages
- validate gRPC request payloads with interceptors
- write custom validation logic with CEL expressions in proto files
- migrate from protoc-gen-validate to protovalidate
- reject invalid data at API boundaries before it corrupts databases

## When to choose
- you use Protocol Buffers and need value-level validation beyond type safety
- you want the same validation rules enforced identically in Go, Java, Python, JS/TS, or C++
- you're starting a new Protobuf project needing schema-embedded constraints
- you need custom rules via CEL expressions alongside standard annotations

## When to avoid
- you're maintaining a legacy PGV project and don't want to migrate (PGV still works in maintenance mode)
- your validation needs are unrelated to Protobuf schemas
- you need runtime-only validation without schema annotations

## Facets
- artifact type: library
- maturity: active
- function: serialization, developer-tools
- domain: apis, developer-tools, backend
- platform: go, python, jvm, cpp, cross-platform
- tags: protobuf, validation, cel, protoc-plugin, grpc, schema-validation, buf, nodejs

## Member repositories
- bufbuild/protovalidate (main) score 94
- bufbuild/protoc-gen-validate (mirror) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:02.349691+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T18:23:07.308118+00:00, confidence not recorded.
  - readme: https://github.com/bufbuild/protovalidate (fetched 2026-08-28T04:05:02.349691+00:00, sha a17524e0d894)
  - homepage: https://protovalidate.com (fetched 2026-08-29T09:14:30.117534+00:00, sha d4e14967c219)
  - site_page: https://protovalidate.com/about (fetched 2026-08-29T09:14:30.126269+00:00, sha 4f094ca21f2e)
  - site_page: https://protovalidate.com/quickstart-go (fetched 2026-08-29T09:14:30.128530+00:00, sha 3c2392b70e7e)
  - site_page: https://protovalidate.com/quickstart-es (fetched 2026-08-29T09:14:30.130450+00:00, sha 308e564d469c)
  - site_page: https://protovalidate.com/quickstart-java (fetched 2026-08-29T09:14:30.132309+00:00, sha 29d50a6b0cb2)
  - site_page: https://protovalidate.com/quickstart-python (fetched 2026-08-29T09:14:30.134169+00:00, sha aa2565804ad7)
  - site_page: https://protovalidate.com/quickstart-cc (fetched 2026-08-29T09:14:30.136207+00:00, sha 054451851812)
  - site_page: https://protovalidate.com/quickstart (fetched 2026-08-29T09:14:30.139182+00:00, sha 5ee3247360f6)
- Data as of 2026-08-30T08:39:29.467469+00:00.