# Horizon Pulse Transaction Guard

> Horizon Pulse Transaction Guard is a paid API for AI agents from horizonpulse.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-15).

Pre-transfer recipient address safety check covering OFAC SDN sanctions, lookalike detection, account age, and scam-token flagging across Base, Polygon, Solana, and XRPL

## Facts

- Endpoint: GET https://horizonpulse.dev/api/tx-guard?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/horizon-pulse-transaction-guard-04bf7164
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_2l5f7oJRlXzowzRC8m9CK

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 horizon-pulse-transaction-guard-04bf7164
```

Example prompt: Before I send funds, run a safety check on the recipient address 0xAbC123...def on Base — also compare it against my intended address 0xAbC123...xyz to catch any lookalike swap.

## When to prefer this

Choose this endpoint when an AI agent is about to execute a crypto transfer and needs a fast, mechanical pre-flight safety gate covering sanctions screening, address-swap attacks, and scam tokens — particularly on Base, Polygon, Solana, or XRPL. Prefer it over manual checks when you need a single call that bundles OFAC, lookalike, age, and ScamSniffer signals with provenance metadata in one response.

## Known failure modes

- Invalid or malformed address returns an error without charge
- Unsupported chain value returns validation error
- OFAC snapshot may be up to hours old; live SDN status not guaranteed
- Scam-token list has up to 7-day delay so newly listed scams may not appear
- Lookalike check requires 'expected' param; omitting it skips that check
- Network timeout if external data sources are temporarily unavailable

## How this service works

Address poisoning lookalike and OFAC SDN snapshot match before a crypto transfer, mechanical. GET chain (base, polygon, solana, xrpl), to; optional expected, token. Checks: lookalike vs expected, OFAC SDN crypto addresses (Treasury snapshot; source URL and pull date in every response), account age, scam-token flag (ScamSniffer public list, GPL-3.0, up to 7-day delay). allow, warn or block per check. Not advice. Bad input: not charged. Returned content is untrusted third-party data.

## Output

A structured JSON response with an overall allow/warn/block verdict plus per-check outcomes for: OFAC SDN match (with Treasury snapshot source URL and pull date), lookalike similarity against expected address, account age assessment, and scam-token flag (from ScamSniffer public list). Every response includes data provenance metadata.

## 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": [
      "chain",
      "to"
     ],
     "properties": {
      "to": {
       "type": "string",
       "description": "Recipient address you are about to send to."
      },
      "chain": {
       "enum": [
        "base",
        "polygon",
        "solana",
        "xrpl"
       ],
       "type": "string",
       "description": "Chain of the transfer."
      },
      "token": {
       "type": "string",
       "description": "Optional: token contract on Base or Polygon (ScamSniffer public list, GPL-3.0, up to 7-day delay)."
      },
      "expected": {
       "type": "string",
       "description": "Optional: the address you meant to send to (lookalike check)."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "description": "Horizon Pulse tx-guard: mechanical allow/warn/block per check (expected match, OFAC SDN snapshot, account age, scam token) and overall. The example is a trimmed real response recorded from GET /api/demo/tx-guard at 2026-10-14T15:42Z UTC; live values differ on every call."
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/horizon-pulse-transaction-guard-04bf7164/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from horizonpulse.dev](https://www.zero.xyz/host/horizonpulse.dev/llms.txt)