x402 census · agent402.tools · 5876fef8fd87 · JSON

POST /api/mev-builder-share

live

Builder market share aggregated over the last N MEV-Boost blocks via the Flashbots relay. Returns per-builder block count, share percent, total ETH paid to proposers, and average per block. Use to track block-builder concentration or detect a new builder gaining share.

Verdict: live. The unpaid GET reached a valid 402. The live amount equals the catalog price.

Facts from the catalogs

Field Value

URL https://agent402.tools/api/mev-builder-share

Method POST

Price $0.002 USDC = 2000 atomic units of 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913

Network eip155:8453 (base); also accepts eip155:137, eip155:42161, eip155:143, eip155:43114, eip155:1329, eip155:10, eip155:4663, eip155:42220, solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp, stellar:pubnet

payTo 0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0

Seller agent402.tools

Catalogs cdp (row updated 2026-09-30), payai (row updated 2026-07-01)

Listed since (lower bound) 2026-07-01 (earliest catalog timestamp; catalogs report last-update times only)

Last catalog update 2026-09-30

CDP quality counters 2 calls and 1 unique payers in 30 days, last call 2026-09-22 (catalog-reported, not verified on chain)

Category (keyword rule) crypto-data

Templated path no

x402Version in catalog 2

Service name / tags MEV builder share · crypto, mev, flashbots, builder-share, concentration

Unpaid probe (census of 2026-09-30)

Field Value

Probed at 2026-09-30T23:39:02.725Z

HEAD 402

GET 402

Verdict live live: valid 402 to an unpaid GET

402 carried in body

x402Version in the 402 2

accepts[0] {"scheme":"exact","network":"eip155:8453","amount":"2000","payTo":"0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0","asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","maxTimeoutSeconds":300,"extra":{"name":"USD Coin","version":"2"}}

Live amount equals catalog price yes

Live payTo equals catalog payTo yes

extensions.bazaar in the 402 yes

PAYMENT-REQUIRED header no

WWW-Authenticate offer Payment id="l6-ZK73sfWCVy0uEKMJMOw45ZmE6

Content type / server / CORS application/json / railway-hikari / *

Latency 3,245 ms

Error Payment required

No hourly re-probe has reached this resource yet; the cron covers a rotating slice of 150 per hour.

On-chain facts for the payTo (public address)

Field Value

Distinct payers 120

Payments 1,253

USDC volume $12.29

Median payment $0.003

First / last payment 2026-06-18 / 2026-09-30

Sampler-shaped share of payments 61.8%

Payers that are not samplers 2

Source forensics-2026-09-30

Address 0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0 (contract: EIP7702StatelessDeleGator)

Declared input and output (extensions.bazaar)

{
 "input": {
  "body": {
   "window": 100
  },
  "bodyType": "json",
  "method": "POST",
  "type": "http"
 },
 "output": {
  "type": "json",
  "example": {
   "builders": [
    {
     "avgEthPerBlock": 0.082305,
     "blocks": 42,
     "builderPubkey": "0x9000...",
     "builderShort": "0x90000000…abcdef",
     "sharePct": 42,
     "totalEthToProposers": 3.456789
    }
   ],
   "relay": "flashbots",
   "uniqueBuilders": 5,
   "windowBlocks": 100
  }
 }
}

Try it (unpaid: shows the 402)

curl -si -X POST 'https://agent402.tools/api/mev-builder-share' -H 'accept: application/json' -H 'content-type: application/json' --data '{}'

The catalog declares POST. A 402 answer carries the payment requirements in the JSON body and, for x402 v2, base64 in the PAYMENT-REQUIRED header. This page never sends a payment.

Paid checks (x402, USDC on Base)

GET https://bazaar.agentexchange.work/r/5876fef8fd87/probe.json re-runs this probe right now for $0.01 and writes the result here. POST https://bazaar.agentexchange.work/featured with {"id":"5876fef8fd87"} places this resource at the top of the report and search pages for 30 days for $1.00, labelled. Unpaid requests answer 402 with the terms. Pricing.

Catalog references: PayAI listing status · agentic.market (CDP Bazaar front end) · this record as JSON · all resources on agent402.tools.