# Almanac Timestamp & Verify (locomot.io)

> Almanac Timestamp & Verify (locomot.io) is a paid API for AI agents from almanac.locomot.io, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).

Creates or verifies a cryptographic timestamp commitment for a piece of text or SHA-256 hash using drand randomness beacons

## Facts

- Endpoint: GET https://almanac.locomot.io/timestamp
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/almanac-timestamp-verify-locomot-io-0d40a03b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ciiIprVLqfuCUOywbnFCQ

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 almanac-timestamp-verify-locomot-io-0d40a03b
```

Example prompt: Create a cryptographic timestamp stamp for the text 'Contract v3 signed by Alice and Bob on 2025-06-01' — I need a drand-anchored proof I can use to show this document existed before a specific point in time.

## When to prefer this

Use this endpoint when you need a publicly verifiable, beacon-anchored cryptographic proof that a piece of data (text or hash) existed at or before a specific point in time. It is ideal for legal timestamping, audit trails, document notarization, and smart contract anchoring where you want a decentralized, drand-based proof rather than a centralized timestamp authority. Prefer this over generic hash registries when you need the drand randomness beacon proof chain and the not-earlier-than guarantee.

## Known failure modes

- Missing required 'op' or 'data'/'hash' query parameter returns an error
- Invalid hex digest (not 64 hex chars) causes a malformed request error
- Specifying a non-existent or future drand round for verify may return not-found
- Network unavailability of the drand beacon causes a service error
- Payment not attached or insufficient USDC results in HTTP 402 before processing

## How this service works

Verifiable timestamp (trustless proof-of-existence / freshness proof): bind a hash to a drand round for an anti-backdating receipt — proves data existed no earlier than a public instant, with no trusted timestamp authority. Privacy: stamp an opaque sha256 digest.

## Output

Returns a JSON object containing the operation type (stamp or verify), a commitment string, a SHA-256 digest of the input, the drand round number used, the beacon proof object, the UTC time of that round, a not-earlier-than timestamp, a flag indicating whether the result is deterministic given the round, and the engine identifier.

## 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",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "op": {
       "enum": [
        "stamp",
        "verify"
       ],
       "type": "string",
       "description": "operation; default stamp"
      },
      "data": {
       "type": "string",
       "description": "text to stamp (sha256'd)"
      },
      "hash": {
       "type": "string",
       "description": "OR a 64-hex sha256 digest (private)"
      },
      "round": {
       "type": "integer",
       "description": "pin a drand round; verify requires it"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "properties": {
    "op": {
     "type": "string"
    },
    "claim": {
     "type": "string"
    },
    "proof": {
     "type": "object"
    },
    "round": {
     "type": "integer"
    },
    "beacon": {
     "type": "object"
    },
    "digest": {
     "type": "string"
    },
    "engine": {
     "type": "string"
    },
    "commitment": {
     "type": "string"
    },
    "digest_source": {
     "type": "string"
    },
    "round_time_utc": {
     "type": "string"
    },
    "not_earlier_than": {
     "type": "string"
    },
    "deterministic_given_round": {
     "type": "boolean"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/almanac-timestamp-verify-locomot-io-0d40a03b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from almanac.locomot.io](https://www.zero.xyz/host/almanac.locomot.io/llms.txt)