JSON Representation

Objects are exchanged as flat JSON objects: one property per field, keyed by the field's name. Each data type has a fixed encoding, which is the same in request bodies (Create, Patch) and in responses (Get one, list rows). Relations are not embedded objects; they are URIs.

Data types

Data type	JSON	Example
TEXT	string	"Acme B.V."
LONGTEXT	string	"Line one\nLine two"
TEXTBLOCK	string of HTML	"<p>Signed on <b>1 March</b>.</p>"
EMAIL	string	"jane.smith@example.com"
INTEGER	number	42
DECIMAL	number	1234.5678
PERCENTAGE	number	0.21
BOOLEAN	boolean	true
DATE	string, yyyy-MM-dd	"2019-03-01"
DATETIME	string, ISO-8601 with offset	"2026-09-24T09:12:31Z"
TIME	string, ISO-8601 local time	"14:30"
LIST	string, the list key	"bv"
CURRENCY	object	{ "currency": "EUR", "amount": 1250.50, "decimals": 2 }
HYPERLINK	object	{ "name": "Website", "href": "https://www.example.com" }
MULTILINGUAL	object	{ "defaultLanguage": "en", "translations": { "en": "Invoice", "nl": "Factuur" } }
FILE, IMAGE	object	See Files.
JSON	object or array	See JSON.
SECRET	string, write-only	See SECRET.

Text types

TEXT, LONGTEXT and TEXTBLOCK are plain strings.

• TEXTBLOCK is HTML. On input it is sanitised: only a basic set of formatting tags and attributes is kept, and anything else, such as <script>, is removed.
• EMAIL is checked against an e-mail address pattern. A value that doesn't match is rejected with 400 Bad Request.

Numbers

INTEGER, DECIMAL and PERCENTAGE are JSON numbers in responses. On input, a numeric string ("42") is accepted as well.

• INTEGER rejects a value with a fractional part (42.5). 42.0 is accepted and stored as 42.
• DECIMAL keeps the precision it was sent with. There is no rounding and no floating-point conversion.
• PERCENTAGE is a fraction, not the percentage itself: 1 means 100%, 0.21 means 21%. The name refers to how the value is interpreted for display, not its scale — the generated UI formats it as value * 100 with a % suffix.

Booleans

BOOLEAN is true or false. On input, true and the string "true" are true; any other value is stored as false, including "yes" and 1.

Dates and times

Type	Input	Output
DATE	yyyy-MM-dd	Same.
DATETIME	ISO-8601 with an offset or Z: "2026-09-24T11:12:31+02:00", "2026-09-24T09:12:31Z". A value without an offset is rejected.	Always in UTC, with Z.
TIME	HH:mm or HH:mm:ss, optionally with fractions of a second	Same format, without a time zone.

A value in another format is rejected with 400 Bad Request. A DATE has no time zone.

Lists

A LIST field holds the key of an entry in the field's list, not its translated label. A key that is not in the list is rejected with 400 Bad Request (Unknown list value). Responses also return the key; the labels in each language come from the metadata.

Currency

{ "currency": "EUR", "amount": 1250.50, "decimals": 2 }

Property	Required	Meaning
currency	Yes	ISO 4217 currency code.
amount	Yes	The amount as a number. An object whose amount is null or missing counts as an empty value, which clears the field.
decimals	No	The number of decimals to keep. If you set it, the amount is rounded to that number of decimals (half up); if you leave it out, the amount is stored as sent. Responses always include it, as null when it isn't set.

Hyperlinks

{ "name": "Website", "href": "https://www.example.com" }

href must be a valid absolute URL, or the value is rejected with 400 Bad Request. name is optional; when it is missing, responses show the href as the name.

Multilingual text

{
  "defaultLanguage": "en",
  "translations": { "en": "Invoice", "nl": "Factuur", "de": "Rechnung" }
}

translations maps a language code to the text in that language, and defaultLanguage names the main language. Both properties are required, and the request always replaces the whole value — to change one translation, send all of them.

Files

FILE and IMAGE fields have the same encoding. In responses they are an object with a download link:

{
  "contentType": "application/pdf",
  "fileName": "signed-contract.pdf",
  "size": 48213,
  "href": "/data/2f9c6e1a-7b34-4d58-9c21-0a5e8f1b2c3d/download/c4a9e2f7-1b6d-4e38-9f05-8a3d7b2c6e91/3fa85f64-5717-4562-b3fc-2c963f66afa6"
}

On input, the value is the object returned by the upload, with a /binaries/{id} href. A file that is already attached may also be sent back as just its href string. The whole flow is described in Files.

JSON

A JSON field holds structured data written by the platform itself, such as the output of an AI task or a gateway. In responses it is returned as the JSON object or array it contains; a value that isn't valid JSON is returned as a string. See Data Types › JSON.

SECRET

A SECRET field is write-only. You send it as a string in a create or patch. It is never included in a response, not even masked — the property is simply absent. Only scripts can read the stored value. See Data Types › SECRET.

Multiple values

A field with multiple: true is a JSON array of values of its data type, in both directions:

{ "tags": ["urgent", "tax", "2026"] }

On input, null entries are skipped and duplicate values are stored only once. An empty array clears the field.

Fields with history

A field with historyEnabled: true keeps its earlier values, each with the date until which it was valid. Such a field is an object in responses:

{
  "legalName": {
    "current": "Acme Holding B.V.",
    "history": [
      { "value": "Acme B.V.", "until": "2024-06-30" }
    ]
  }
}

On input you can send either form:

• The full object: current and history are both stored as sent. Use this to add or correct a history entry: read the field, change it, and send the whole object back.
• A plain value ("legalName": "Acme Group B.V."): it becomes the new current, and the stored history is discarded. To change a field with history without losing its history, send the full object with the old value added to history.

Relations

Relations are set and read as URIs. The key is the REST name of the relation's class — singular for a single-valued relation, plural for a multi-valued one (see Qualified names and URLs):

	Request body	Response
Single-valued	"country": "/data/{tenant}/countries/{id}"	_links.country: { "href": "...", "name": "Netherlands" }
Multi-valued	"employees": ["/data/{tenant}/persons/{id}", ...]	_links.employees: { "href": "<related list>", "values": [{ "href": "...", "name": "..." }] }

In responses, relations appear only under _links, never as top-level properties. When you send them back, send the href strings, not the { href, name } objects. See Get one and Patch for the details, including how a multi-valued relation is replaced as a whole.

Empty values

Direction	Rule
Request	null and "" (also a string of only spaces) clear a field. A key that is left out leaves the field unchanged. For a multi-valued field, [] clears it.
Response	An empty field is left out. Responses never contain "field": null; a missing property means "no value".

A property in a request that is not a field or relation of the object is ignored without an error — see Request body.