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format JSON Schema Keyword

Use format to ask validators to check common string shapes such as email, uri, date-time, hostname, uuid, and ip-address.

Validation

Schema template

Try in Validator

JSON Schema

{
  "type": "string",
  "format": "email"
}

Valid example JSON

"[email protected]"

Invalid example JSON

"hello at example dot com"

Fields

FieldTypeRequiredDescription
formatstringYesNames the semantic string format. Validator behavior can vary, so confirm whether your validator treats format as assertion or annotation.

How to use this schema

Pair format with type: string. For important business rules, add pattern or application-level checks because some validators treat format as optional annotation.

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

pattern JSON Schema KeywordUse pattern to require a string to match a regular expression, such as an internal code, slug, SKU, or constrained identifier.type JSON Schema KeywordUse type to require a JSON value to be a string, number, integer, boolean, object, array, or null before other rules are evaluated.minLength JSON Schema KeywordUse minLength to require a string to contain at least a minimum number of Unicode characters.