# SignalHarness FX Pair List

> SignalHarness FX Pair List is a paid API for AI agents from signalharness.ai, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

Returns a searchable, paginated list of available foreign exchange currency pairs from a curated dataset.

## Facts

- Endpoint: POST https://signalharness.ai/api/agent/services/fx_pair_list/invoke
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/signalharness-fx-pair-list-eb994b40
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_mprqBZh5b9ev0FEOZ-pP5

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 signalharness-fx-pair-list-eb994b40 -d '<json body>'
```

Example prompt: Can you give me a list of all available FX currency pairs that include USD — up to 50 results?

## When to prefer this

Choose this endpoint when you need to enumerate or search the catalog of supported foreign exchange currency pairs, especially before querying rates or data for a specific pair. It is useful for validation, discovery, and populating dropdowns or agent context with available instruments.

## Known failure modes

- Limit out of range (must be 1–256) returns validation error
- Query string exceeding 32 characters rejected
- No pairs found matching query returns empty array with count 0
- Payment failure results in 402 response before execution
- Service temporarily unavailable returns non-succeeded status

## How this service works

Explore 330 pay-per-call x402 API services and 27 agent-native digital products, with Base USDC pricing, secure Polar checkout, and free discovery.

## Output

Returns a JSON object containing an array of FX currency pairs, a count of matched pairs, source metadata (dataset name, provider, source URL, attribution, free access URL, retrieval timestamp), any warnings, and a payment receipt with execution details including latency, payment ID, and result hash.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "limit": {
   "type": "integer",
   "maximum": 256,
   "minimum": 1
  },
  "query": {
   "type": "string",
   "maxLength": 32,
   "minLength": 0
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "replay": false,
  "result": {
   "count": 0,
   "pairs": [
    {
     "asOf": "2026-09-12",
     "base": "USD",
     "name": "example",
     "quote": "USD",
     "symbol": "EUR/USD"
    }
   ],
   "source": {
    "notice": "example",
    "dataset": "example",
    "provider": "example",
    "sourceUrl": "https://example.com/resource",
    "attribution": "example",
    "retrievedAt": "example0000000000000",
    "freeAccessUrl": "https://example.com/resource"
   },
   "warnings": [
    "Verify the caller-supplied data before relying on this result."
   ],
   "retrievedAt": "example0000000000000"
  },
  "status": "succeeded",
  "receipt": {
   "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
   "usage": [],
   "status": "succeeded",
   "network": "eip155:8453",
   "artifacts": [],
   "endedAtMs": 0,
   "latencyMs": 0,
   "paymentId": "example-payment",
   "receiptId": "example-receipt",
   "requestId": "example-request",
   "serviceId": "fx_pair_list",
   "executionId": "example-execution",
   "startedAtMs": 0,
   "amountAtomic": "5000",
   "resultSha256": "02d1c22e5d813f355ce7cc193a8ab2f7fb53afdb3e560a5df3189c383841045e",
   "serviceVersion": "1.0.0",
   "settlementReference": "0x0000000000000000000000000000000000000000000000000000000000000000"
  },
  "artifacts": [],
  "requestId": "example-request",
  "executionId": "example-execution"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/signalharness-fx-pair-list-eb994b40/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from signalharness.ai](https://www.zero.xyz/host/signalharness.ai/llms.txt)