# rate-hub API – /v1/rates (Crypto & Asset Rates Lookup)

> rate-hub API – /v1/rates (Crypto & Asset Rates Lookup) is a paid API for AI agents from x402-v1.sky-1.org, paid per call via x402, $0.05/call, status unknown (last checked 2026-10-11).

Returns current prices, 24h change, market cap, and volume for one or more crypto assets (e.g. BTC, ETH) via an aggregated data feed.

## Facts

- Endpoint: POST https://x402-v1.sky-1.org/v1/rates?utm_source=zero.xyz
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/rate-hub-api-v1-rates-crypto-asset-rates-lookup-036cff7f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_4o5j9aleM7UVZpVsbuRha

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 rate-hub-api-v1-rates-crypto-asset-rates-lookup-036cff7f -d '<json body>'
```

Example prompt: What are the current prices, 24-hour changes, and market caps for Bitcoin and Ethereum right now?

## When to prefer this

Choose this endpoint when you need aggregated, real-time cryptocurrency price data (USD prices, 24h change, market cap, volume) with per-call micropayment access via USDC on Base (x402 protocol) and no API key registration required. Prefer it for lightweight, pay-as-you-go crypto rate lookups without a subscription commitment.

## Known failure modes

- 402 Payment Required — no valid Bearer token or payment provided; response includes offer details and x402 payment instructions
- 402 with snake_case error — token unknown, spent, or expired
- 404 — endpoint not found on classic (non-x402) deployment
- 500 — upstream aggregator data unavailable or server error
- Malformed request body returns 402 (not 400) for payment-related issues

## How this service works

**Access.** A deployment runs in one of two modes and the free `GET /v1/x402` tells which: it answers `200` with the offer on an x402 deployment and `404` on a classic one.

- **x402 deployment** (the public one). There is no API key. A payment of USDC on Base buys a credit token for a pack of requests. Call a paid route without credentials: the answer is `402` with the offer in the `PAYMENT-REQUIRED` header (base64 JSON) and in the body. Pay by repeating the request with a `PAYMENT-SIGNATURE` header (base64 JSON x402 v2 `PaymentPayload`, scheme `exact`). The paying response is the normal answer plus `X-Credit-Token` (your token), `X-Credit-Remaining` and `PAYMENT-RESPONSE`. Keep the token and send `Authorization: Bearer <token>` on every later request. A token that is unknown, spent or expired, and any payment that cannot be accepted, answer `402` again: every payment problem is a `402` with a snake_case reason in `error`, never a `400`. On `/mcp` the same problems come back as `200` tool results, see `/mcp`. A `503` with `Retry-After` can mean the same payment is being processed right now: retry shortly. If the payment facilitator does not answer, the answer is `502` and nothing is charged.
- **Classic deployment.** The client sends its key in the `X-API-Key` header. A missing or unknown key answers `401`.

Paid routes: every `/v1` path except `GET /v1/x402`, and MCP `tools/call`. Free: `GET /v1/x402`, `/healthz`, `/readyz`, `/version`, `/openapi.yaml`, `/openapi.json` and `/.well-known/x402` (x402 deployments only), `/docs` (with `/docs/behavior` and `/docs/behavior.md`), `/llms.txt`, and the MCP methods `initialize`, `ping`, `tools/list` and `notifications/*`. On an x402 deployment every served request costs one credit, whatever its status, except `5xx`, which is refunded. Requests that match no route (`404`, `405`) are free.

Client rules, in order. Read these before the paths.

- Ignore unknown JSON fields. The server adds fields without a new major version.
- Map an unknown enum value to an `unknown` case. A Swift `Codable` enum with no fallback crashes the decode and drops the whole response.
- Honor `Retry-After` on `429` and `503`. The header is always an integer number of seconds, never an HTTP-date. `pending` rates carry `retry_after` in seconds for that asset only.
- Fiat live quotes: `source_code` `s10` is a live rate table with no observation time of its own, so `as_of` is the fetch instant (about every 30 minutes by default); `day_change_pct` and `high_volatility` stay a move against the last rate of the previous UTC day, not against the previous poll. A currency that table does not cover keeps its last quote (`source_code` `s3`, `as_of` midnight UTC of that document's date) and turns `stale` after the fiat stale limit. Fiat daily quotes (`/v1/rates/daily`, `source_code` `s3`): `as_of` is midnight UTC of the upstream document date (the rate for that UTC calendar day), not the fetch instant. When present, optional `day` (`YYYY-MM-DD`) repeats that calendar day explicitly. Optional `fetched_at` is when rate-hub last received the live quote from upstream.
- Freshness: live responses (`/v1/rates`, `/v1/top`, `/v1/assets`, `/v1/meta`, errors) carry `Cache-Control: no-cache`, so a client or CDN must ask again before reusing one. A refresh always returns the newest snapshot rate-api holds, so the collector's polling cadence is the floor on freshness. Judge a price by `as_of` (when the price was observed) and `fetched_at` (when rate-hub last refreshed it), not by when you asked.
- `server_time`, quote `as_of`, and quote `fetched_at` use RFC3339 with millisecond precision (fractional seconds trimmed; no sub-millisecond noise).
- Integration tests can observe `pending` by requesting a catalog uid that has no row in the loaded in-memory quote snapshot (for example a cold asset before the first lazy fetch).
- Back off exponentially with jitter. Do not retry in a tight loop.
- Prices and percent changes are decimal strings, never JSON numbers. Parse them with a decimal type. Do not use binary floating point.

Edge cases this schema does not show (dynamic coins and their changing uids, placeholder icons, series limits, data lifetimes) are in the [behaviour notes](/docs/behavior) ([raw Markdown](/docs/behavior.md)).

Conventions: lowercase `snake_case`, full field names, statuses as strings, versioned under `/v1`. Changes inside v1 are additive only.

Prices are rounded to 10 significant digits. This service is an indicative cache, not an oracle. Live `/v1/rates` quotes are not a full history product; additive `/v1/rates/daily` returns one immutable USD (or requested `vs`) rate per catalog uid per UTC calendar day for backfill and prewarm (see those paths for day definitions and archive limits).

## Output

Returns a JSON object containing a build version, server timestamp, and an array of rate objects — each with symbol, type (crypto), USD price, 24h price change, market rank, market cap, 24h volume, status, fetched_at timestamp, and aggregated source code.

## 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",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object"
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST",
      "PUT",
      "PATCH"
     ],
     "type": "string"
    },
    "headers": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "build": "0.18.0-a1b2c3d",
  "rates": [
   {
    "uid": 200000001,
    "type": "crypto",
    "as_of": "2026-10-10T12:00:00.000Z",
    "change": {
     "h24": "1.25",
     "quote": "usd"
    },
    "market": {
     "rank": 1,
     "quote": "usd",
     "market_cap": "1330000000000",
     "volume_24h": "28000000000"
    },
    "prices": {
     "usd": "67250.12"
    },
    "status": "ok",
    "symbol": "btc",
    "fetched_at": "2026-10-10T12:00:03.000Z",
    "source_code": "agg"
   },
   {
    "uid": 200000002,
    "type": "crypto",
    "as_of": "2026-10-10T12:00:00.000Z",
    "change": {
     "h24": "-0.4",
     "quote": "usd"
    },
    "market": {
     "rank": 2,
     "quote": "usd",
     "market_cap": "314000000000",
     "volume_24h": "14000000000"
    },
    "prices": {
     "usd": "2610.4"
    },
    "status": "ok",
    "symbol": "eth",
    "fetched_at": "2026-10-10T12:00:03.000Z",
    "source_code": "agg"
   }
  ],
  "server_time": "2026-10-10T12:00:03.500Z"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/rate-hub-api-v1-rates-crypto-asset-rates-lookup-036cff7f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-v1.sky-1.org](https://www.zero.xyz/host/x402-v1.sky-1.org/llms.txt)