# Xynaptic Crypto Fear & Greed Index

> Xynaptic Crypto Fear & Greed Index is a paid API for AI agents from api.xynaptic.io, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-02).

Returns the current crypto market sentiment score (0-100) with classification and interpretation, using the alternative.me Fear & Greed index, plus yesterday's and last week's values.

## Facts

- Endpoint: GET https://api.xynaptic.io/v1/crypto-fear-greed?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/xynaptic-crypto-fear-greed-index-5453f42c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_N9Am7FtEkMpjTqcfTqj1t

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 xynaptic-crypto-fear-greed-index-5453f42c
```

Example prompt: What's the current crypto fear and greed index — is the market in extreme fear or greed right now, and how does it compare to yesterday and last week?

## When to prefer this

Choose this endpoint when you need a quick, pre-aggregated crypto market sentiment snapshot without building your own data pipeline. It is ideal for agents that need to contextualize trading decisions, include sentiment in reports, or trigger workflows based on market mood. It wraps the widely-trusted alternative.me index with agent-friendly interpretation hints, making it more actionable than raw index feeds.

## Known failure modes

- Upstream alternative.me index unavailable — returns error or stale data
- Rate limiting if called excessively in a short period
- Payment failure (x402) if USDC balance is insufficient — returns 402 status

## How this service works

Xynaptic Crypto Fear & Greed — the market sentiment thermometer (alternative.me index, 0-100): current value, yesterday, last week, classification (extreme fear..extreme greed) + interpretation hint for agents. GET no params.

## Output

Returns a JSON object with the current fear & greed index value (0-100), its text classification (e.g. 'Extreme Fear', 'Fear', 'Neutral', 'Greed', 'Extreme Greed'), the equivalent values for yesterday and last week, and an interpretation hint to help agents act on the data.

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

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/xynaptic-crypto-fear-greed-index-5453f42c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.xynaptic.io](https://www.zero.xyz/host/api.xynaptic.io/llms.txt)