TToolumina

pattern JSON Schema Keyword

Use pattern to require a string to match a regular expression, such as an internal code, slug, SKU, or constrained identifier.

String

Schema template

Try in Validator

JSON Schema

{
  "type": "string",
  "pattern": "^[A-Z]{3}-\\d{3}$"
}

Valid example JSON

"ABC-123"

Invalid example JSON

"abc-123"

Fields

FieldTypeRequiredDescription
patternECMAScript regex stringYesThe regular expression is not implicitly anchored. Add ^ and $ when the whole string must match.

How to use this schema

Use pattern for precise string shapes. Keep regexes readable and test them with valid and invalid examples before placing them in API contracts.

Version support and combinations

This keyword or pattern is commonly supported across modern JSON Schema workflows. Check your validator for Draft-04, Draft-07, 2019-09, and 2020-12 behavior before relying on newer composition or conditional features.

Common combination: pair this reference with type, required, and properties so validation errors are specific enough for API clients and form users.

Batch validation seed

Want to validate JSON Schema in bulk? Toolumina Pro can grow into batch validation for 100+ files, saved schemas, and repeatable API contract checks.

Related reference pages

format JSON Schema KeywordUse format to ask validators to check common string shapes such as email, uri, date-time, hostname, uuid, and ip-address.minLength JSON Schema KeywordUse minLength to require a string to contain at least a minimum number of Unicode characters.maxLength JSON Schema KeywordUse maxLength to limit a string to a maximum number of Unicode characters.