# Polyform Crypto Fear & Greed Index

> Polyform Crypto Fear & Greed Index is a paid API for AI agents from api.polyform.org, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-02).

Returns the current Crypto Fear & Greed Index value (0–100) with classification label, sourced from alternative.me

## Facts

- Endpoint: GET https://api.polyform.org/v1/crypto/fear-greed?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/polyform-crypto-fear-greed-index-91dbbb94
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Dp1h8GAJOGP0uNcETRQq7

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 polyform-crypto-fear-greed-index-91dbbb94
```

Example prompt: What's the current crypto fear and greed index — is the market in fear or greed territory right now, and what's the exact score?

## When to prefer this

Choose this endpoint when you need a quick, no-auth, pay-per-call crypto sentiment score without setting up API keys or accounts. Ideal for agents that need occasional market mood checks at minimal cost ($0.002/call) via USDC micropayment on Base. Prefer over alternative.me direct if you want a machine-payable, agent-native interface with no signup friction.

## Known failure modes

- Upstream alternative.me data unavailable — stale or missing response
- Payment failure via x402 — 402 returned if USDC micropayment not completed
- Rate or network issues on Base blockchain for payment verification

## How this service works

Pay-per-call data endpoints for AI agents. USDC on Base via x402. No account, no API key — one micropayment per call.

## Output

Returns a JSON object with: the current numeric score (0–100), a classification string (e.g. 'Fear', 'Extreme Greed'), a scale description, the data source (alternative.me), and the timestamp of the reading.

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

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "asOf": "2026-09-28T00:00:00.000Z",
  "scale": "0=extreme fear, 100=extreme greed",
  "value": 45,
  "source": "alternative.me Crypto Fear & Greed Index",
  "classification": "Fear"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/polyform-crypto-fear-greed-index-91dbbb94/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.polyform.org](https://www.zero.xyz/host/api.polyform.org/llms.txt)