Nyckel supports three input data types — Text, Image, and Tabular — and the request/response shape of every invoke and sample endpoint depends on which one your Function is configured for.

Text

Requests pass text data as a JSON string. Responses return the text the same way.

Image

Image data can be sent two ways:

Raw image bytes in a multipart/form-data request, or
A data URI inside an application/json request.

Image responses come back as a JSON string, either as a URL pointing to the image resource or as a data URI containing the image bytes.

Tabular

Tabular data is sent as a JSON object — {"key": "value", ...}. Keys may be either field ids or field names. Values must be:

JSON strings for Text or Image fields,
JSON numbers for Number fields.

For image fields inside a tabular row, use either an internet-accessible image URL or a data URI. Tabular responses come back as a JSON object with string or number values.