# Glassnode Herfindahl Index (Decentralization Metric)

> Glassnode Herfindahl Index (Decentralization Metric) is a paid API for AI agents from x402.glassnode.com, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-14).

Returns the Herfindahl Index for a crypto asset, measuring supply concentration/decentralization as the sum of squared address shares of current supply.

## Facts

- Endpoint: GET https://x402.glassnode.com/v1/metrics/distribution/herfindahl
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/glassnode-herfindahl-index-decentralization-metric-05f5ef2b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_I87hHySTue3i36xGHfL2g

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 glassnode-herfindahl-index-decentralization-metric-05f5ef2b
```

Example prompt: Can you pull the Glassnode Herfindahl Index for Bitcoin to see how concentrated BTC supply is across addresses right now — give me the latest 24h data in JSON?

## When to prefer this

Use this endpoint when you need a quantitative, Glassnode-sourced measure of supply concentration or decentralization for a specific crypto asset. It is ideal for on-chain analysts, portfolio managers, or researchers comparing the degree of wealth concentration across blockchain networks over time. Prefer this over generic holder-count or whale metrics when a single normalized index of address-share inequality is needed.

## Known failure modes

- Missing required 'a' (asset) parameter returns a 400 or validation error
- Unsupported asset symbol (e.g. a non-indexed token) may return empty data or 404
- Invalid interval or format enum values result in a schema validation error
- Payment not fulfilled (x402 protocol) results in a 402 Payment Required response
- Rate limiting or quota exhaustion may return 429 Too Many Requests

## How this service works

Herfindahl Index — Herfindahl Index, originally a measure of competition, is adapted here as a metric for decentralization. It is defined as the sum of squared address shares of current supply across the network. Data by Glassnode.

## Output

A time-series array of data points, each with a UNIX timestamp (t) and a scalar Herfindahl Index value (v) representing the sum of squared address shares of circulating supply at that interval. Lower values indicate more decentralized supply distribution; higher values indicate greater concentration.

## 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",
     "required": [
      "a"
     ],
     "properties": {
      "a": {
       "type": "string",
       "description": "Asset symbol, e.g. BTC, ETH"
      },
      "c": {
       "enum": [
        "native"
       ],
       "type": "string",
       "description": "Currency for denominated values, e.g. usd, native"
      },
      "f": {
       "enum": [
        "csv",
        "json"
       ],
       "type": "string",
       "description": "Response format: json or csv"
      },
      "i": {
       "enum": [
        "24h"
       ],
       "type": "string",
       "description": "Time interval / resolution, e.g. 24h, 1w, 1month"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "array",
     "items": {
      "type": "object",
      "required": [
       "t"
      ],
      "properties": {
       "o": {
        "type": "object",
        "description": "Nested value object for multi-field metrics (e.g. OHLC)"
       },
       "t": {
        "type": "integer",
        "description": "UNIX timestamp (seconds, UTC) for the start of the interval"
       },
       "v": {
        "type": "number",
        "description": "Scalar metric value at the given timestamp"
       }
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/glassnode-herfindahl-index-decentralization-metric-05f5ef2b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.glassnode.com](https://www.zero.xyz/host/x402.glassnode.com/llms.txt)