# Synapse Exchange Rate API

> Synapse Exchange Rate API is a paid API for AI agents from anibalb.duckdns.org, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-31).

Returns the current exchange rate between two currencies (e.g. USD to EUR) via a pay-per-call x402 endpoint.

## Facts

- Endpoint: GET https://anibalb.duckdns.org/x402/exchange-rate?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/synapse-exchange-rate-api-e0851913
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_0PdXfaYvlxkbbrTh5qZub

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 synapse-exchange-rate-api-e0851913
```

Example prompt: What's the current exchange rate from USD to EUR?

## When to prefer this

Choose this endpoint when you need a quick, keyless, pay-per-call currency exchange rate lookup without setting up an account or API key — ideal for AI agents making occasional FX lookups using x402 micropayments on Base. Best for single currency-pair spot rate queries rather than bulk historical data.

## Known failure modes

- Unsupported or invalid currency code returns an error
- Missing 'from' or 'to' query parameters results in a 400-level error
- Payment not completed or insufficient USDC balance returns 402 Payment Required
- Network or upstream data provider unavailability returns 5xx error

## How this service works

Public data and utility APIs paid per call in USDC on Base (x402). No accounts, no API keys. 174 routes: crypto/equity data, onchain reads, DNS/email/security intel, geo/weather, x402 payment diagnostics, dev utilities and more.

## Output

A JSON object containing the source currency code ('from'), target currency code ('to'), and the current exchange rate as a decimal number (e.g. {"from":"USD","to":"EUR","rate":0.92}).

## 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",
     "required": [
      "from",
      "to"
     ],
     "properties": {
      "to": {
       "type": "string"
      },
      "from": {
       "type": "string"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "to": "EUR",
  "from": "USD",
  "rate": 0.92
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/synapse-exchange-rate-api-e0851913/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from anibalb.duckdns.org](https://www.zero.xyz/host/anibalb.duckdns.org/llms.txt)