●

Umpire

Verification PAYMENT-READY

payment-ready until 2026-09-21

A neutral third party for agent commerce. Buy an Ed25519 signed pass or fail verdict on a deliverable against a machine readable acceptance spec (JSON Schema, JSON path, content hash, regex, length, live URL probe), verifiable offline by anyone against a published key. The witness tier ($0.25) fetches one public URL and signs what it saw (final URL, status, resolved address, TLS fingerprint, headers, body sha256) as proof against agent false success. Also sells reputation reads on merchant wallets built only from payment verified feedback. $0.01 to $5.00 per document, USDC on Base or Solana, no account.

Pay from $0.01 to $5.00 in USDC on Base / Solana, settled onchain via the x402 protocol, no signup, no API key needed.

measured since 2026-09-03 (start of our harvest window) · $0 all-time · last settled 2026-09-12

BASE URL https://umpire.vimabrosta.com │ WEBSITE https://umpire.vimabrosta.com/manual │ ENDPOINTS 5 │ NETWORK Base / Solana │ ASSET USDC │ MEMBER SINCE 2026-09-14 │ MONITORED SINCE 2026-09-14

VERDICT

ranking generation 3

solid 87/100 #10 of 87 in Verification by measured score

What the score read on this service: status online, 100% uptime 24h (no 30d window yet), 80ms response p95, x402 compliance 14 of 14, $0.01 price against the category, on-chain traction measured. Each of those is measured, and each is published in full below.

The score comes from our own monitoring, never from reviews, operator claims, or a language model: reliability, x402 compliance, price against the category, a deterministic risk flag, and a small on-chain traction term, weighted by ranking generation 3. It is not placement anyone can buy: the paid verify tier is reported beside it and is not one of its inputs. Every component below stays published and read-only.

It is a score inside Verification, and only there: price and speed are scored against the whole category field, every listing in it that carries no danger flag, the scored service included, which here means 87 listings, this one among them. That set is wider than the 87 the position above is counted against, because a listing we have measured too little of to rank still sits in the field the price and the speed are normalized over. The same service in a different field would read differently. The same engine answers GET /api/v1/best, and asked for a different pool (the whole directory, or another filter) it returns a different number for this service under this same ranking generation. Neither is more correct: they answer different questions, and the methodology states which is which.

Bands on the 0 to 100 measured score: strong at 93 and above, solid from 75, mixed from 55, weak below 55. Price and speed are scored against the whole category field, every listing in it that carries no danger flag, the scored service included, so the score places a service in its own field.

ALTERNATIVES IN VERIFICATION

Other Verification services in this directory, ordered by the same measured score. The figures are ours: 30-day uptime from our own probes, 30-day settlement volume read on-chain (a conservative undercount, and null where we cannot measure it, never a zero).

Ranked alternative x402 services in the same category, with band, measured score, 30-day uptime and 30-day on-chain settlement volume
SERVICE	BAND	SCORE	UPTIME 30D	VOL 30D
scvd.store — evidence observatory for the x402 economy	strong	93	100%	$1.0k
Rubric Protocol — Post-Quantum AI Attestation	solid	92	100%	$13.10
ForgeMesh x402 Notary	solid	89	---	$0
LION — Verified Company & Compliance Data	solid	89	100%	$7.00
10x402	solid	88	100%	$2.50

5 of 86 other ranked services in Verification

ASSESSMENT

updated 2h ago

The parts the verdict above is computed from, each with its proof. Click any chip. Measured values stay read-only; unknown is honest, and an unknown is never counted as a zero.

reliability 100%

uptime 24h: -
uptime 7d: -
uptime 30d: -
uptime 90d: -
response p95: 80ms
avg response: 80ms
total checks: 1

Measured on the unpaid 402 handshake, not the paid call. A service can 402 correctly and still fail after payment.

compliance A (14/14)

14 of 14 x402 conformance checks pass. Full checklist below.

jump to compliance checklist

price $0.01 to $5.00 (p42 in Verification)

price (min): $0.01
price (max): $5.00
category percentile (min): p42 in Verification
category percentile (max): p93 in Verification
endpoints / prices: 5 / 5
model: tiered
stability: 100%

risk clean

No deterministic risk flag. Risk fires only on an exact blocklist match, or a reserved-brand name with a mismatched verified payTo. Never from low uptime, a high price, or a model guess.

domain age: 52d
registrar: Cloudflare, Inc.
hosting: custom
domain created: 2026-07-24

Identity facts, not a risk score.

traction $0.00 30d · 0 buyers

volume 30d: $0.00
buyers 30d: 0
settlements 30d: 0
measured since: 2026-09-03 (start of our harvest window)
last settlement: 2026-09-12
top buyer share: -
trend 7d vs 30d: -
networks: eip155:8453, solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdpKuc147dw2N9d
volume all-time: $0
settlements all-time: 0
median settlement 30d: -
max settlement 30d: -
settled via: -

Conservative undercount: only USDC settlements via facilitators we measure are counted. A measured floor, not an estimate.

Top buyer share is a concentration signal, not part of the ranking score.

WHAT IT DOES

ai-derived

No AI synthesis has been produced for this service yet.

ENDPOINTS

Service endpoints with HTTP method, path, description, pricing, and network
METHOD	PATH	PRICE	NETWORK	ASSET	402 CHANNEL
GET	/v1/reputation	$0.01	Base/Solana	USDC	header
GET	/v1/verdicts/basic	$1.00	Base/Solana	USDC	header
GET	/v1/verdicts/probe	$2.00	Base/Solana	USDC	header
GET	/v1/verdicts/sworn	$5.00	Base/Solana	USDC	header
GET	/v1/verdicts/witness	$0.25	Base/Solana	USDC	header

5 endpoints

REQUEST / RESPONSE EXAMPLE

An unpaid request to GET /v1/reputation returns HTTP 402 with the payment terms. Settle onchain via your facilitator, then retry with the X-Payment header.

// request

curl -i 'https://umpire.vimabrosta.com/v1/reputation'

// 402 response (captured by monitor) · 5 payloads · click to expand

[
  {
    "error": "Payment required",
    "accepts": [
      {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "extra": {
          "name": "USD Coin",
          "version": "2"
        },
        "payTo": "0xd63e74bCB00757C8fDb1817F1558ed8b97C608b6",
        "amount": "1000000",
        "scheme": "exact",
        "network": "eip155:8453",
        "maxTimeoutSeconds": 120
      },
      {
        "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
        "extra": {
          "feePayer": "GVJJ7rdGiXr5xaYbRwRbjfaJL7fmwRygFi1H6aGqDveb"
        },
        "payTo": "8c9r8kxtkcsv7wARq3wBy2csm1ySRQQmdy6hrPnga4qs",
        "amount": "1000000",
        "scheme": "exact",
        "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
        "maxTimeoutSeconds": 120
      },
      {
        "asset": "So11111111111111111111111111111111111111112",
        "extra": {
          "feePayer": "GVJJ7rdGiXr5xaYbRwRbjfaJL7fmwRygFi1H6aGqDveb"
        },
        "payTo": "8c9r8kxtkcsv7wARq3wBy2csm1ySRQQmdy6hrPnga4qs",
        "amount": "9795407",
        "scheme": "exact",
        "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
        "maxTimeoutSeconds": 120
      }
    ],
    "resource": {
      "url": "https://umpire.vimabrosta.com/v1/verdicts/basic",
      "mimeType": "application/json",
      "description": "Get a signed pass/fail verdict on a deliverable against your acceptance spec, synchronously. Deterministic checks only: JSON Schema conformance, JSON path assertions, sha256 content hash, regex, length bounds. Returns an Ed25519 signed verdict document any third party can verify offline; suitable as evidence for escrow release. $1.00 per verdict, no account."
    },
    "x402Version": 2
  },
  {
    "error": "Payment required",
    "accepts": [
      {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "extra": {
          "name": "USD Coin",
          "version": "2"
        },
        "payTo": "0xd63e74bCB00757C8fDb1817F1558ed8b97C608b6",
        "amount": "250000",
        "scheme": "exact",
        "network": "eip155:8453",
        "maxTimeoutSeconds": 120
      },
      {
        "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
        "extra": {
          "feePayer": "GVJJ7rdGiXr5xaYbRwRbjfaJL7fmwRygFi1H6aGqDveb"
        },
        "payTo": "8c9r8kxtkcsv7wARq3wBy2csm1ySRQQmdy6hrPnga4qs",
        "amount": "250000",
        "scheme": "exact",
        "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
        "maxTimeoutSeconds": 120
      },
      {
        "asset": "So11111111111111111111111111111111111111112",
        "extra": {
          "feePayer": "GVJJ7rdGiXr5xaYbRwRbjfaJL7fmwRygFi1H6aGqDveb"
        },
        "payTo": "8c9r8kxtkcsv7wARq3wBy2csm1ySRQQmdy6hrPnga4qs",
        "amount": "2448852",
        "scheme": "exact",
        "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
        "maxTimeoutSeconds": 120
      }
    ],
    "resource": {
      "url": "https://umpire.vimabrosta.com/v1/verdicts/witness",
      "mimeType": "application/json",
      "description": "Proof that the world changed the way your agent says it did. One live probe of a public URL against your expectation (HTTP status, keyword, CSS selector, JSON path), answered synchronously as an Ed25519 signed verdict that embeds a signed observation: final URL, resolved address, TLS certificate fingerprint, response headers, raw body sha256, timestamp. A stake free witness against false success, priced to clear unattended wallet caps. $0.25 per verdict, no account."
    },
    "x402Version": 2
  },
  {
    "error": "Payment required",
    "accepts": [
      {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "extra": {
          "name": "USD Coin",
          "version": "2"
        },
        "payTo": "0xd63e74bCB00757C8fDb1817F1558ed8b97C608b6",
        "amount": "2000000",
        "scheme": "exact",
        "network": "eip155:8453",
        "maxTimeoutSeconds": 120
      },
      {
        "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
        "extra": {
          "feePayer": "GVJJ7rdGiXr5xaYbRwRbjfaJL7fmwRygFi1H6aGqDveb"
        },
        "payTo": "8c9r8kxtkcsv7wARq3wBy2csm1ySRQQmdy6hrPnga4qs",
        "amount": "2000000",
        "scheme": "exact",
        "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
        "maxTimeoutSeconds": 120
      },
      {
        "asset": "So11111111111111111111111111111111111111112",
        "extra": {
          "feePayer": "GVJJ7rdGiXr5xaYbRwRbjfaJL7fmwRygFi1H6aGqDveb"
        },
        "payTo": "8c9r8kxtkcsv7wARq3wBy2csm1ySRQQmdy6hrPnga4qs",
        "amount": "19590813",
        "scheme": "exact",
        "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
        "maxTimeoutSeconds": 120
      }
    ],
    "resource": {
      "url": "https://umpire.vimabrosta.com/v1/verdicts/probe",
      "mimeType": "application/json",
      "description": "Signed verdict with live verification: everything in basic plus up to three network probes of public URLs (HTTP status, keyword, CSS selector, JSON path on the response). Use it to verify a delivered site, API, or published artifact actually works before releasing escrow. Synchronous, Ed25519 signed, verifiable offline. $2.00 per verdict, no account."
    },
    "x402Version": 2
  },
  {
    "error": "Payment required",
    "accepts": [
      {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "extra": {
          "name": "USD Coin",
          "version": "2"
        },
        "payTo": "0xd63e74bCB00757C8fDb1817F1558ed8b97C608b6",
        "amount": "5000000",
        "scheme": "exact",
        "network": "eip155:8453",
        "maxTimeoutSeconds": 120
      },
      {
        "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
        "extra": {
          "feePayer": "GVJJ7rdGiXr5xaYbRwRbjfaJL7fmwRygFi1H6aGqDveb"
        },
        "payTo": "8c9r8kxtkcsv7wARq3wBy2csm1ySRQQmdy6hrPnga4qs",
        "amount": "5000000",
        "scheme": "exact",
        "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
        "maxTimeoutSeconds": 120
      },
      {
        "asset": "So11111111111111111111111111111111111111112",
        "extra": {
          "feePayer": "GVJJ7rdGiXr5xaYbRwRbjfaJL7fmwRygFi1H6aGqDveb"
        },
        "payTo": "8c9r8kxtkcsv7wARq3wBy2csm1ySRQQmdy6hrPnga4qs",
        "amount": "48977032",
        "scheme": "exact",
        "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
        "maxTimeoutSeconds": 120
      }
    ],
    "resource": {
      "url": "https://umpire.vimabrosta.com/v1/verdicts/sworn",
      "mimeType": "application/json",
      "description": "Highest assurance verdict: all checks run twice, spaced about a minute apart, and pass only if both passes pass, so a deliverable staged briefly cannot sneak through. Asynchronous: instant first pass result, webhook or free polling for the signed final document. Designed for the ERC-8183 evaluator role and escrow release evidence. $5.00 per verdict."
    },
    "x402Version": 2
  },
  {
    "error": "Payment required",
    "accepts": [
      {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "extra": {
          "name": "USD Coin",
          "version": "2"
        },
        "payTo": "0xd63e74bCB00757C8fDb1817F1558ed8b97C608b6",
        "amount": "10000",
        "scheme": "exact",
        "network": "eip155:8453",
        "maxTimeoutSeconds": 120
      },
      {
        "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
        "extra": {
          "feePayer": "GVJJ7rdGiXr5xaYbRwRbjfaJL7fmwRygFi1H6aGqDveb"
        },
        "payTo": "8c9r8kxtkcsv7wARq3wBy2csm1ySRQQmdy6hrPnga4qs",
        "amount": "10000",
        "scheme": "exact",
        "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
        "maxTimeoutSeconds": 120
      },
      {
        "asset": "So11111111111111111111111111111111111111112",
        "extra": {
          "feePayer": "GVJJ7rdGiXr5xaYbRwRbjfaJL7fmwRygFi1H6aGqDveb"
        },
        "payTo": "8c9r8kxtkcsv7wARq3wBy2csm1ySRQQmdy6hrPnga4qs",
        "amount": "97955",
        "scheme": "exact",
        "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
        "maxTimeoutSeconds": 120
      }
    ],
    "resource": {
      "url": "https://umpire.vimabrosta.com/v1/reputation",
      "mimeType": "application/json",
      "description": "Read the payment verified reputation of any merchant wallet address. Every score aggregates only feedback whose submitter proved a settled on-chain USDC payment to that merchant (at least the published floor) and signed with the paying wallet, so no row is free and wash patterns are exposed by independence signals. Returns a signed report: outcome counts, count and amount weighted fulfillment rates, unique payers, volume, payer concentration. $0.01 per read."
    },
    "extensions": {
      "bazaar": {
        "info": {
          "input": {
            "type": "http",
            "method": "GET",
            "queryParams": {
              "merchant": "0x1234567890abcdef1234567890abcdef12345678"
            }
          },
          "output": {
            "type": "json",
            "example": {
              "merchant": "0x1234567890abcdef1234567890abcdef12345678",
              "feedback_count": 12,
              "fulfillment_rate": 0.917,
              "weighted_fulfillment_rate": 0.94
            }
          }
        },
        "name": "Umpire",
        "tags": [
          "verification",
          "verdict",
          "evaluator",
          "witness",
          "reputation",
          "receipts",
          "trust"
        ],
        "schema": {
          "type": "object",
          "$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",
                  "required": [
                    "merchant"
                  ],
                  "properties": {
                    "merchant": {
                      "type": "string",
                      "pattern": "^0x[0-9a-fA-F]{40}$"
                    }
                  }
                }
              },
              "additionalProperties": false
            },
            "output": {
              "type": "object",
              "required": [
                "type"
              ],
              "properties": {
                "type": {
                  "type": "string"
                },
                "example": {
                  "type": "object"
                }
              }
            }
          }
        },
        "discoverable": true
      }
    },
    "x402Version": 2
  }
]

OVER TIME

All charts use the 7d selector; each series spans only the dates it has data for. Every series is also served as JSON at /api/v1/services/umpire/price, /scores, /volume and /buyers. On-chain volume and distinct buyers are measured over the service's settlement address and are a conservative undercount (only settlements that reach a measured facilitator are counted). The on-chain series roll up hourly, so the latest day can be up to about an hour behind; distinct buyers are counted per payout address, so a service that settles to more than one address is an upper bound.

UPTIME

7d UPTIME 100%

RESPONSE TIME

AVG RESP 179ms

PRICE (captured 402, USD)

Median across 5 endpoints. Use the selector to isolate one.

SUB-SCORES (uptime + x402 compliance)

checklist grew 11->14 on 2026-07-28; a step here is a metric change, not a regression

VOLUME (on-chain settlement, USD)

DISTINCT BUYERS

COMPLIANCE

14/14 checks pass · grade A

last 402 captured 2026-09-14 · last up 2026-09-14

402 payload captured
accepts[] array present
payTo address recoverable
payTo at accepts[0].payTo (conformant shape)
payTo is a valid on-chain address
atomic price declared
atomic price in a sane range
asset (token) address declared
network resolves to CAIP-2
payment scheme declared
served over HTTPS
declares the current x402 version (2)
EIP-712 domain parameters present on every EVM entry
x402 v2 envelope delivered in the payment-required header

SITE PILLARS

homepage reachable
openapi doc
pricing page
llms.txt
robots.txt
terms page

recent checks (9) live · click to expand

TIME STATUS RESP CAUSE

21:31:01 UTC ● SLOW 271ms

21:15:00 UTC ● OK 134ms

20:59:01 UTC ● OK 238ms

20:43:00 UTC ● OK 109ms

20:27:00 UTC ● OK 92ms

20:11:01 UTC ● OK 190ms

19:55:01 UTC ● SLOW 273ms

19:39:01 UTC ● OK 223ms

19:23:00 UTC ● OK 80ms

EMBED THIS BADGE

Show that Umpire is monitored on x402-list. Paste this on your site or README, it links back to this live listing.

status

Umpire uptime on x402-list — live uptime

// HTML

<a href="https://x402-list.com/services/umpire?utm_source=badge&utm_medium=referral&utm_campaign=embed">
  <img src="https://x402-list.com/badge/umpire.svg" alt="Umpire listed on x402-list" height="28">
</a>

// Markdown

[![Umpire on x402-list](https://x402-list.com/badge/umpire.svg)](https://x402-list.com/services/umpire?utm_source=badge&utm_medium=referral&utm_campaign=embed)

// HTML · live uptime variant

<a href="https://x402-list.com/services/umpire?utm_source=badge&utm_medium=referral&utm_campaign=embed">
  <img src="https://x402-list.com/badge/umpire.svg?data=uptime" alt="Umpire uptime on x402-list" height="28">
</a>

RUN THIS SERVICE?

Keep this listing accurate: propose changes to the name, description, website, category or add new endpoints to monitor. Ownership is verified with a domain proof and every change is reviewed manually; measured data stays read-only.

[ update this listing ]

Earn the verified tier: x402list pays a real call to this endpoint and, if it delivers, the service is delivery-verified. The fee covers the cost of the probe, not the badge; there is no refund if the call does not deliver. Agent and API only, no in-browser signing. See /api.

[ verify this service ($0.25) ]

To request delisting, email info@x402-list.com or update your listing at /services/umpire/update.