Data Type Validation

Data types validate claim values and shape the issuance form. You configure named instances of the system's base types (STRING, NUMBER, DATE, and so on), then reference those instances by name when you create credential and proof schemas. The same configuration applies when verifying: presented claims are validated against the data types in your proof schema.

You must configure at least one instance of each base type you plan to use. For all base types and their parameters, see the data types reference.

tip

Wallets use data types differently. See Data Type Extraction.

Basic structure

datatype:
  EMAIL:
    display: "datatype.email"
    type: "STRING"
    order: 110
    params:
      public:
        pattern: '^[\w\-\.]+@([\w\-]+\.)+[\w\-]{2,4}$'
        placeholder: "abc@abc.com"
        autocomplete: true
        supportedInputMode: TEXT
        error:
          en: "Please enter a valid email address"
          de: "Bitte geben Sie eine gültige E-Mail-Adresse ein"

Parameters

Validation parameters control how claim values are validated during issuance and verification:

• pattern: Regex pattern for string validation
• min/max: Range limits for numbers and dates
• formats: Date/datetime format requirements
• accept: Allowed MIME types for files
• fileSize: Maximum file size in bytes

UI parameters shape the issuance form. They are passed to the frontend and are not validated by the backend:

• supportedInputMode: Input element type (for example TEXT, DATE_PICKER, FILE_UPLOAD)
• placeholder: Hint text shown in empty fields
• autocomplete: Enables browser autocomplete
• showAs: Display mode for images
• error: Custom error message shown when validation fails; supports multiple languages

Multiple instances of one base type

Instances can share a base type while using different validation rules, UI parameters, and display names. For example, EMAIL alongside a generic STRING, or BIRTH_DATE alongside a general DATE:

datatype:
  STRING:
    display: "datatype.string"
    type: "STRING"
    order: 100
    params:
      public:
        supportedInputMode: TEXT
  EMAIL:
    display: "datatype.email"
    type: "STRING"
    order: 110
    params:
      public:
        pattern: '^[\w\-\.]+@([\w\-]+\.)+[\w\-]{2,4}$'
        placeholder: "abc@abc.com"
        autocomplete: true
        supportedInputMode: TEXT
        error:
          en: "Please enter a valid email address"
  DATE:
    display: "datatype.date"
    type: "DATE"
    order: 300
    params:
      public:
        formats: ["date", "datetime"]
        preferredFormat: "datetime"
        supportedInputMode: DATE_PICKER
  BIRTH_DATE:
    display: "datatype.birth_date"
    type: "DATE"
    order: 310
    params:
      public:
        formats: ["date"]
        preferredFormat: "date"
        min: 1900-01-01
        max: "NOW"
        supportedInputMode: DATE_PICKER
        error:
          en: "Please choose a date between 1900-01-01 and today"