# Basescan Token Holders & Concentration Metrics

> Basescan Token Holders & Concentration Metrics is a paid API for AI agents from origin-mcp.fly.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-15).

Returns holder count, top holders list, and Herfindahl-Hirschman Index (HHI) concentration metrics for a given token on Base

## Facts

- Endpoint: GET https://origin-mcp.fly.dev/mcp/tools/basescan_token_holders
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/origin-mcp-fly-dev-e00d3060
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_IWePmMIW4zIqiKgX947d_

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 origin-mcp-fly-dev-e00d3060
```

Example prompt: Can you pull up the holder count and top holders for token contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base, and show me the HHI concentration score so I can see if it's whale-dominated?

## When to prefer this

Use this endpoint when you need on-chain holder distribution data for a token on the Base network, especially when assessing decentralization, rug-pull risk, or whale concentration via the HHI metric. Prefer this over generic block explorers when you need structured, pre-computed concentration metrics rather than raw data.

## Known failure modes

- Invalid or non-existent contract address returns an error or empty result
- Token not indexed on Basescan returns no data
- Rate limiting or upstream Basescan API unavailability causes timeout
- Non-Base network contract addresses may not resolve correctly

## How this service works

Get holder count and top holders for a token with concentration metrics (HHI)

## Output

Returns total number of token holders, a ranked list of top wallet addresses with their balance and percentage of supply, and an HHI (Herfindahl-Hirschman Index) score indicating how concentrated ownership is among top holders.

## Request schema (JSON Schema)

```json
{
 "properties": {
  "input": {
   "required": [
    "method"
   ],
   "properties": {
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/origin-mcp-fly-dev-e00d3060/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from origin-mcp.fly.dev](https://www.zero.xyz/host/origin-mcp.fly.dev/llms.txt)