# x402 Seller Leaderboard by USDC Inflow

> x402 Seller Leaderboard by USDC Inflow is a paid API for AI agents from mcpfax-intel.bowling-anthony.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-21).

Returns a ranked leaderboard of x402 sellers ordered by observed USDC inflow, with payer diversity metrics, HHI market concentration scores, and wash-trade risk flags.

## Facts

- Endpoint: GET https://mcpfax-intel.bowling-anthony.workers.dev/seller-rank?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-seller-leaderboard-by-usdc-inflow-7e6d2ff8
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_DvAX_D-WBHiNvRk7UyXFF

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 x402-seller-leaderboard-by-usdc-inflow-7e6d2ff8
```

Example prompt: Show me the top x402 sellers ranked by USDC inflow in the AI tools category — I want to see their payer counts, HHI concentration scores, and any wash-risk flags so I know who's actually earning legitimately.

## When to prefer this

Use this endpoint when you need to identify who is genuinely earning in a specific x402 category, assess market concentration among sellers, or screen for wash-trade risk. Prefer this over generic blockchain analytics when you specifically want x402 protocol seller rankings with built-in concentration and fraud-risk metrics. Use sibling endpoints for unmet demand analysis or emerging seller discovery.

## Known failure modes

- Sellers below observation floor returned as unrated rather than ranked — not an error but may appear as missing data
- Payer-graph discount suppressed and seller not ranked if wallet scan coverage is insufficient
- Empty result set if no sellers meet the observation floor in the requested category
- Invalid category or date range returns an error response
- Payment of 0.01 USDC required per call — unpaid requests rejected

## How this service works

Leaderboard of x402 sellers by observed USDC inflow, with distinct payers, an HHI concentration measure and wash-risk flags. Sellers below the observation floor are returned unrated, not accused. The payer-graph discount applies only where wallet scan coverage supports it. HHI measures concentration, not common control.

## Output

An ordered list of x402 sellers with their USDC inflow totals, distinct payer counts, HHI market concentration score for the category, wash-risk boolean flags, and an 'unrated' status for sellers below the observation floor. The payer-graph discount is included only when wallet scan coverage is sufficient.

## 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"
    }
   },
   "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/x402-seller-leaderboard-by-usdc-inflow-7e6d2ff8/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from mcpfax-intel.bowling-anthony.workers.dev](https://www.zero.xyz/host/mcpfax-intel.bowling-anthony.workers.dev/llms.txt)