# hcrb.in FX Best-Execution Quote

> hcrb.in FX Best-Execution Quote is a paid API for AI agents from hcrb.in, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-29).

Races four DEX aggregators (KyberSwap, ParaSwap, OpenOcean, Relay) simultaneously for USDC/EURC swaps on Base, returning the best rate with Pyth real-time pricing and ECB MiCA-compliant FX proof

## Facts

- Endpoint: POST https://hcrb.in/fx/best-execution-quote?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/hcrb-in-fx-best-execution-quote-4e65e31c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_DvPXkBe5PykPk_p89JqW1

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 hcrb-in-fx-best-execution-quote-4e65e31c -d '<json body>'
```

Example prompt: I need to swap 10000 USDC for EURC on Base — can you race all four aggregators (KyberSwap, ParaSwap, OpenOcean, Relay) and get me the best-execution quote with a MiCA-compliant ECB FX proof for my wallet 0xAbC123...?

## When to prefer this

Choose this endpoint when you need a MiCA-compliant best-execution proof for USDC/EURC stablecoin swaps on Base, or when regulatory documentation of the FX rate source (ECB + Pyth) is required. Prefer it over single-DEX quotes when you want simultaneous comparison across KyberSwap, ParaSwap, OpenOcean, and Relay to guarantee best price. Ideal for compliance-conscious treasury operations, DeFi agents operating under European MiCA obligations, or any scenario where auditability of the FX rate matters alongside execution quality.

## Known failure modes

- Invalid or unsupported token pair (only USDC↔EURC on Base supported) — returns 400 with token validation error
- Invalid taker_address (not a valid EVM address) — returns 400
- sell_amount_human is zero or negative — returns 400
- All four aggregators fail or return no liquidity — returns 500 or empty best quote
- Payment not received (x402 protocol failure) — returns 402
- Pyth or ECB feed temporarily unavailable — may return degraded response without proof or timeout

## How this service works

4-Way Base & Polygon Stablecoin FX Meta-Aggregator Race (KyberSwap, ParaSwap, OpenOcean, Relay) + Pyth Real-Time & 30-Currency ECB MiCA Best-Execution Proof

## Output

Returns the winning DEX aggregator quote for the requested USDC/EURC or EURC/USDC swap on Base, including the best output amount, routing details, a Pyth Network real-time FX price, and an ECB MiCA-compliant best-execution proof covering 30 currencies — enabling regulatory-grade documentation of the FX trade.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "buy_token",
  "sell_amount_human",
  "sell_token",
  "taker_address"
 ],
 "properties": {
  "buy_token": {
   "type": "string",
   "description": "EURC or USDC on Base"
  },
  "sell_token": {
   "type": "string",
   "description": "USDC or EURC on Base"
  },
  "taker_address": {
   "type": "string",
   "description": "Base EVM wallet address executing the swap"
  },
  "sell_amount_human": {
   "type": "number",
   "description": "Amount to swap (e.g. 10000)"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "application/json",
 "description": "4-Way Base Meta-Aggregator Race (KyberSwap, ParaSwap, OpenOcean, Relay) + Pyth Real-Time & ECB MiCA Best-Execution Proof"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/hcrb-in-fx-best-execution-quote-4e65e31c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from hcrb.in](https://www.zero.xyz/host/hcrb.in/llms.txt)