API reference · Trust Fabric

Verify an Ed25519 signature against a registered principal

POST /fabric/identity/principals/{principal_id}/verify

Last reviewed 2026-11-06

POST /fabric/identity/principals/{principal_id}/verify

Parameters

Name	In	Type	Meaning
`principal_id` required	path	string

Request body

SignatureVerify (required)

Field	Type	Meaning
`message` required	string	min length `1` · max length `8192`
`signature` required	string	base64 Ed25519 signature over message bytes min length `1`

Responses

Status	Meaning	Body
`200`	Successful Response	JSON
`401`	The X-API-Key header is missing, or the key is unknown, revoked or replaced.	`Error`
`403`	The key is valid but may not do this (for example an agent key approving its own held action).	`Error`
`422`	Validation Error	`HTTPValidationError`
`429`	Rate limit or monthly quota reached. Wait for the number of seconds in Retry-After when it is sent.	`Error`

Try it

Your API key X-API-Key Remember the key in this tab onlyprincipal_id pathRequest body application/json

This call changes data in the account the key belongs to.

The request goes from your browser straight to this site. Your key is not stored unless you tick the box, and then only in this tab's session storage.

Code

curl -sS -X POST 'https://cainstudio.online/fabric/identity/principals/<principal_id>/verify' \
  -H "X-API-Key: $CAIN_API_KEY" \
  -H 'Content-Type: application/json' \
  -d '{"message": "message", "signature": "signature"}'

import json, os, urllib.request

req = urllib.request.Request('https://cainstudio.online/fabric/identity/principals/<principal_id>/verify', method='POST',
    headers={"X-API-Key": os.environ["CAIN_API_KEY"], "Content-Type": "application/json"},
    data=json.dumps({
      "message": "message",
      "signature": "signature"
    }).encode())
with urllib.request.urlopen(req, timeout=60) as r:
    print(r.status, json.load(r))

const res = await fetch("https://cainstudio.online/fabric/identity/principals/<principal_id>/verify", {
  method: "POST",
  headers: {
    "X-API-Key": process.env.CAIN_API_KEY!,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "message": "message",
    "signature": "signature"
  }),
});
console.log(res.status, await res.json());

Schemas used

Error · HTTPValidationError · SignatureVerify · ValidationError

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