Validation

Add OpenAPI schema validation constraints to properties using validation annotations. These annotations work in both OpenAPI and JSON Schema modes.

Number Validation

@OpenApiNumberValidation(
    minimum = "0",
    maximum = "10000",
    exclusiveMaximum = "10000",
    multipleOf = "0.01"
)
val price: Double = 0.0

In OAS 3.1.0, exclusiveMinimum and exclusiveMaximum are standalone numeric values (not booleans). Use minimum for inclusive bounds and exclusiveMinimum/exclusiveMaximum when the bound itself should be excluded.

Property	Description
minimum	Minimum value (inclusive)
maximum	Maximum value (inclusive)
exclusiveMinimum	Exclusive minimum value (OAS 3.1.0 numeric)
exclusiveMaximum	Exclusive maximum value (OAS 3.1.0 numeric)
multipleOf	Must be a multiple of this

String Validation

@OpenApiStringValidation(
    minLength = "1",
    maxLength = "100",
    pattern = "^[a-zA-Z0-9_]+$"
)
val username: String = ""

@OpenApiStringValidation(format = "email")
val email: String = ""

Property	Description
minLength	Minimum string length
maxLength	Maximum string length
pattern	Regex pattern
format	String format (email, uri, ...)

Array Validation

@OpenApiArrayValidation(
    minItems = "1",
    maxItems = "50",
    uniqueItems = true
)
val tags: List<String> = emptyList()

Property	Description
minItems	Minimum number of items
maxItems	Maximum number of items
uniqueItems	All items must be unique

Object Validation

@OpenApiObjectValidation(
    minProperties = "1",
    maxProperties = "20"
)
val settings: Map<String, String> = emptyMap()

Property	Description
minProperties	Min properties
maxProperties	Max properties

Combining Annotations

Validation annotations combine with other property annotations:

@OpenApiStringValidation(
    minLength = "1",
    maxLength = "200"
)
@OpenApiRequired
@OpenApiDescription("Search query string")
val query: String = ""

@OpenApiNumberValidation(
    minimum = "1",
    maximum = "100"
)
@OpenApiExample(raw = "20")
val pageSize: Int = 20