# SperaxOS Fear & Greed Index API

> SperaxOS Fear & Greed Index API is a paid API for AI agents from chat.sperax.io, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Returns the current and historical Crypto Fear & Greed Index value and classification, payable per-request with USDC via x402.

## Facts

- Endpoint: GET https://chat.sperax.io/api/x402/fear-greed
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/speraxos-fear-greed-index-api-511624ec
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_j3mUx01uCTX_X_VNvn0vC

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 speraxos-fear-greed-index-api-511624ec
```

Example prompt: What is the current crypto fear and greed index, and can you show me the last 7 days of readings so I can see how sentiment has shifted?

## When to prefer this

Choose this endpoint when you need real-time or recent historical Crypto Fear & Greed Index data without managing API keys, and you are already operating in an x402 USDC payment-capable environment on Base. Ideal for DeFi agents, trading bots, or portfolio management tools that need a quick sentiment signal payable programmatically per call.

## Known failure modes

- Payment not included or insufficient USDC — returns 402 Payment Required
- limit parameter exceeds maximum of 30 — may return error or truncated data
- Network or upstream data source unavailable — metadata.error field will be populated
- Invalid limit type (non-integer) — request may be rejected with a 400 error

## How this service works

AI-powered DeFi intelligence APIs payable via the x402 HTTP payment protocol. No API key required — pay per request with USDC on Base. Identity-only (SIWX) endpoints are free for wallets with an agentcash identity.

## Output

Returns a JSON array of data points each containing a numeric index value (0-100), a human-readable classification string (e.g. 'Extreme Fear', 'Fear', 'Neutral', 'Greed', 'Extreme Greed'), and a Unix timestamp. Also returns the index name and any error metadata.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "limit": {
   "type": "integer",
   "description": "Number of historical data points (default: 1, max: 30)"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "data": {
   "type": "array",
   "items": {
    "type": "object",
    "properties": {
     "value": {
      "type": "string",
      "example": "72"
     },
     "timestamp": {
      "type": "string",
      "example": "1712524800"
     },
     "value_classification": {
      "type": "string",
      "example": "Greed"
     }
    }
   }
  },
  "name": {
   "type": "string",
   "example": "Fear and Greed Index"
  },
  "metadata": {
   "type": "object",
   "properties": {
    "error": {
     "type": "string",
     "nullable": true
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/speraxos-fear-greed-index-api-511624ec/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from chat.sperax.io](https://www.zero.xyz/host/chat.sperax.io/llms.txt)