Ask for one attribute, and receive an answer

POST /identity/attributes · Identity · version 2026-09-14

Requests a predicate rather than a document. You receive the answer — true, false, or a value — never the underlying document.

The person approves in their wallet. Both sides get a receipt naming exactly what was shared and why it was asked.

The call returns immediately with a request_id. The answer arrives on your webhook endpoint when the person responds.

Base URL

https://api.sidaxis.com/v1 in production, https://sandbox.api.sidaxis.com/v1 in sandbox.

Name	In	Type	Required	Description
Authorization	header	string	required	Bearer sk_live_… in production, sk_test_… in sandbox.
Sidaxis-Version	header	string	optional	Dated version. Pin it in production.
Idempotency-Key	header	string	optional	Replaying a key returns the original request_id instead of asking the person twice.

Field	Type	Required	Description
facetoken	string	required	Who you are asking.
attribute	enum	required	The single predicate you need. One attribute per request.
purpose	string	optional	Shown to the person when they are asked, and recorded in the receipt.

{
  "facetoken": "0xA1f3c9b27d04",
  "attribute": "over_18",
  "purpose": "Age-restricted checkout"
}

Sent to the person's wallet. Resolve it on your webhook endpoint.

{
  "request_id": "req_6c18b904",
  "status": "pending"
}

not_found, rate_limited. See errors and refusals.

A person can decline. A decline resolves the request; it is not an error on your side.

Ask for the predicate you need, not the document that proves it — over_18 rather than a date of birth.