Signed receipt for a supplied SHA-256 digest

Answeringour last check, 2026-10-01

1 of 1checks answered this week

874 msmedian answer time

$0.01listed price per call

$0.01price it asked us

Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.

Endpoint

POST https://fabair-agents.com/stamp

Category	Everything else
Provider host	fabair-agents.com
Networks	eip155:8453
Payment schemes	exact
Self-reported calls, 30 days	1 from 1 payers (the provider's figure, not ours)

Our checks, last 30 days

Day	Result	HTTP	Asked	Time
2026-10-01	valid payment request	402	$0.01	874 ms

Example input (from the provider)

{
  "body": {
    "digest": "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
    "key_id": "example-agent"
  },
  "bodyType": "json",
  "headers": {
    "X-C1-Operation-Id": "example-unique-operation"
  },
  "method": "POST",
  "type": "http"
}

Promised output schema (from the provider)

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "additionalProperties": false,
  "description": "Signed receipt for a supplied SHA-256 digest. Local untrusted time; no proof of principal authorization.",
  "properties": {
    "input": {
      "additionalProperties": false,
      "properties": {
        "body": {
          "additionalProperties": false,
          "properties": {
            "digest": {
              "maxLength": 64,
              "minLength": 64,
              "pattern": "^[a-fA-F0-9]{64}$",
              "type": "string"
            },
            "key_id": {
              "maxLength": 128,
              "minLength": 1,
              "not": {
                "pattern": "[^A-Za-z0-9_.:@/-]"
              },
              "pattern": "^[A-Za-z0-9_.:@/-]+$",
              "type": "string"
            },
            "note": {
              "maxLength": 200,
              "not": {
                "pattern": "[\u0000-\u001f]"
              },
              "type": "string"
            },
            "principal": {
              "maxLength": 128,
              "minLength": 1,
              "not": {
                "pattern": "[^A-Za-z0-9_.:@/-]"
              },
              "pattern": "^[A-Za-z0-9_.:@/-]+$",
              "type": "string"
            }
          },
          "required": [
            "digest",
            "key_id"
          ],
          "type": "object"
        },
        "bodyType": {
          "const": "json"
        },
        "headers": {
          "additionalProperties": false,
          "properties": {
            "X-C1-Operation-Id": {
              "pattern": "^[a-z0-9_-]{1,64}$",
              "type": "string"
            }
          },
          "required": [
            "X-C1-Operation-Id"
          ],
          "type": "object"
        },
        "method": {
          "enum": [
            "POST"
          ]
        },
        "type": {
          "const": "http"
        }
      },
      "required": [
        "type",
        "method",
        "bodyType",
        "body",
        "headers"
      ],
      "type": "object"
    },
    "output": {
      "additionalProperties": false,
      "properties": {
        "type": {
          "const": "json"
        }
      },
      "required": [
        "type"
      ],
      "type": "object"
    }
  },
  "required": [
    "input"
  ],
  "title": "FABA signed digest stamp",
  "type": "object"
}

This page as JSON