# Crypto ETF Sentinel — Fee War (Expense Ratio Leaderboard)

> Crypto ETF Sentinel — Fee War (Expense Ratio Leaderboard) is a paid API for AI agents from api.cryptoetfsentinel.com, paid per call via x402, $0.1/call, status unknown (last checked 2026-09-15).

Returns the current expense ratio for every trading US spot crypto ETF, sorted cheapest first, with outliers capped at 200bps to filter bad XBRL extractions.

## Facts

- Endpoint: GET https://api.cryptoetfsentinel.com/v1/xbrl/fee-war
- Price: $0.1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/api-cryptoetfsentinel-com-f7956c37
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_5Qdnz7wQhgtBwr9Whtr1q

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 api-cryptoetfsentinel-com-f7956c37
```

Example prompt: Pull up the current expense ratio leaderboard for all trading US spot crypto ETFs — I want to see which ones are cheapest, sorted from lowest fee to highest, with bad XBRL outliers filtered out.

## When to prefer this

Use this endpoint when you need a ranked, clean snapshot of all live US spot crypto ETF fees in one call — especially for fee competition analysis, cheapest-fund selection, or monitoring fee-cutting events. Prefer over single-issuer endpoints when you need the full cohort view rather than one fund's details.

## Known failure modes

- No ETFs in trading status — empty data array returned
- XBRL source data temporarily unavailable — stale or partial results
- Payment not included or insufficient — 402 Payment Required response
- Rate limit exceeded — HTTP 429
- Upstream SEC XBRL pipeline outage — error field populated in response

## How this service works

Crypto ETF Sentinel — Crypto ETF fee comparison: current expense ratio for every trading US spot crypto ETF, cheapest first, outlier-capped at 200 bps to drop bad XBRL extractions. Use when finding the lowest-cost Bitcoin, Ethereum or other crypto ETF, or benchmarking a fee. Optional crypto filter.

## Output

An array of all currently trading US spot crypto ETFs ordered by expense ratio ascending, with each entry including ticker, issuer, and expense ratio in basis points. Values are outlier-capped at 200bps to exclude likely XBRL extraction errors. Includes pagination metadata (total, limit, offset) and an error field.

## Example request

```json
{
 "input": {
  "type": "http",
  "method": "GET",
  "queryParams": {}
 }
}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "properties": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "data": [
   {
    "cik": "0001980994",
    "name": "iShares Bitcoin Trust",
    "ticker": "IBIT",
    "fee_bps": 25,
    "fee_pct": "0.25%"
   }
  ],
  "meta": {
   "total": 1
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/api-cryptoetfsentinel-com-f7956c37/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.cryptoetfsentinel.com](https://www.zero.xyz/host/api.cryptoetfsentinel.com/llms.txt)