# Seneschal Proposer Payment Query

> Seneschal Proposer Payment Query is a paid API for AI agents from api.seneschal.space, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).

Returns the actual ETH payment received by the latest Ethereum block proposer (priority fees + direct coinbase transfers) along with 1-hour aggregate statistics

## Facts

- Endpoint: GET https://api.seneschal.space/v1/q/proposer-payment
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/seneschal-proposer-payment-query-41563f54
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_OKUFiwuvkHto1yUTQAywG

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 seneschal-proposer-payment-query-41563f54
```

Example prompt: What did the proposer of the latest Ethereum block actually get paid — including priority fees and direct coinbase transfers — and what does the 1-hour aggregate look like for mean, median, and p90 proposer payments?

## When to prefer this

Use this endpoint when you need the true validator/proposer payment (priority fees plus direct coinbase transfers) rather than the commonly used but noisy block-value proxy. Ideal for MEV research, validator yield analytics, block builder competitive analysis, or any application requiring accurate on-chain proposer economics rather than estimates.

## Known failure modes

- No recent block data available — returns stale or empty result if chain is not synced
- Rate limiting or payment failure via x402 protocol returns 402 Payment Required
- Missing or malformed query parameters return 400 Bad Request
- Service unavailable returns 503 if the underlying block data feed is down

## How this service works

Single-fact: what did the proposer of the latest block ACTUALLY get paid (priority fees + direct coinbase transfers — the value that reaches the validator, not the noisy block-value proxy)? Returns {block, proposer_payment_eth, builder, tx_count} plus a 1h aggregate {samples, mean_eth, median_eth, p90_eth, max_eth}. Per-block history export: /v1/premium/builder-bids.csv ($0.05, CSV or JSONL).

## Output

Returns a JSON object with: block number, proposer_payment_eth (actual ETH paid), proposer_payment_wei, builder identity, tx_count, timestamp fields (ts_ms, as_of_ms, source_freshness_s), a history_endpoint link, and a 1h aggregate object containing samples count, mean_eth, median_eth, p90_eth, and max_eth.

## Request schema (JSON Schema)

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

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "hour": {
   "max_eth": 0.41,
   "p90_eth": 0.0388,
   "samples": 291,
   "mean_eth": 0.0182,
   "median_eth": 0.0121
  },
  "block": 23012001,
  "ts_ms": 1765531988000,
  "builder": "titan",
  "as_of_ms": 1765532000000,
  "tx_count": 309,
  "history_endpoint": "/v1/premium/builder-bids.csv",
  "source_freshness_s": 9,
  "proposer_payment_eth": 0.010354286,
  "proposer_payment_wei": "10354286568285197"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/seneschal-proposer-payment-query-41563f54/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.seneschal.space](https://www.zero.xyz/host/api.seneschal.space/llms.txt)