valdo

[ 📚 docs ] [ 🐙 github ]

Go package for validating JSON. Can generate JSON Schema (100% compatible with OpenAPI), produces user-friendly errors, supports translations.

You could write OpenAPI documentation by hand (which is very painful) and then use it to validate user input in your HTTP service, but then error messages are very confusing, not user-friendly, and only in English. Or you could write input validation by hand and then maintain the OpenAPI documentation separately but then the two will eventually drift and your documentation will be a lie. Valdo solves all these problems: write validation once using a real programming language, use it everywhere.

Features:

• Mechanism to translate error messages.
• Out-of-the-box translations for some languages.
• Supports the latest JSON Schema specification (2020-12).
• Pure Go.
• No code generation, no reflection, no unsafe code.
• User-friendly error messages.
• Concurrency-safe, no global state.
• Strict by default, without implicit type casting.
• Type-safe, thanks to generics.

Installation

go get github.com/orsinium-labs/valdo

Usage

validator := valdo.Object(
    valdo.Property("name", valdo.String(valdo.MinLen(1))),
    valdo.Property("admin", valdo.Bool()),
)

// validate JSON
input := []byte(`{"name": "aragorn", "admin": true}`)
err := valdo.Validate(validator, raw)

// validate and unmarshal JSON
type User struct {
    Name  string `json:"name"`
    Admin bool   `json:"admin"`
}
user, err := valdo.Unmarshal[User](validator, input)

// generate JSON Schema
schema := valdo.Schema(validator)

See documentation for more.