# Arakel Interval Proof Certificate

> Arakel Interval Proof Certificate is a paid API for AI agents from proof.arakelproof.space, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-15).

Generates a signed, machine-verifiable interval proof certificate for a given time range or numeric interval

## Facts

- Endpoint: GET https://proof.arakelproof.space/v1/certificate
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/arakel-interval-proof-certificate-33daba7a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_qazxDk1F5Y-oiTj9c7cjy

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability arakel-interval-proof-certificate-33daba7a
```

Example prompt: Generate a signed machine-verifiable interval proof certificate for the range January 1 2025 to June 30 2025 with my subject ID 'user-42'.

## When to prefer this

Choose this endpoint when you need a cryptographically signed, tamper-proof certificate proving that a value, event, or entity falls within a specific numeric or time interval. It is particularly suited for compliance workflows, audit trails, or access control systems that require machine-verifiable proof without relying on a centralized trusted authority.

## Known failure modes

- Invalid or malformed interval bounds — returns 400 with validation error
- Missing required subject or interval parameters — returns 400
- Payment not received or insufficient — returns 402
- Internal signing failure — returns 500
- Interval start is after interval end — returns validation error

## How this service works

Machine-verifiable official-source evidence with free preflight and x402 USDC payments on Base.

## Output

A signed, machine-verifiable interval proof certificate returned as a structured document. The certificate cryptographically attests that a subject or value falls within a declared interval, and is designed to be verified programmatically by downstream systems without requiring trust in a third party.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "term",
      "from",
      "to"
     ],
     "properties": {
      "to": {
       "type": "string",
       "format": "date-time",
       "description": "UTC interval end"
      },
      "from": {
       "type": "string",
       "format": "date-time",
       "description": "UTC interval start"
      },
      "term": {
       "type": "string",
       "description": "Federal Register event or search term"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "detail": "certificate",
  "result": "OBSERVED|NOT_OBSERVED|INCONCLUSIVE",
  "schema": "arakel.intervalproof.v1",
  "source": {
   "id": "federal-register"
  },
  "coverage": {
   "sufficient": true
  },
  "signature": {
   "alg": "Ed25519"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/arakel-interval-proof-certificate-33daba7a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from proof.arakelproof.space](https://www.zero.xyz/host/proof.arakelproof.space/llms.txt)