x402 List

x402 Protocol Service Directory

Watchtower

Verification PAYMENT-READY

payment-ready until 2026-09-08

Deterministic sanctions screening for AI agents across OFAC/UN/EU/UK lists; x402 USDC on Base, no signup.

Pay from $0.02 per request in USDC on Base, settled onchain via the x402 protocol, no signup, no API key needed.

measured since 2026-08-19 (start of our harvest window) · $0.04 all-time · settled via coinbase

BASE URL https://watchtower-api.com WEBSITE https://watchtower-api.com ENDPOINTS 1 NETWORK Base ASSET USDC MEMBER SINCE 2026-07-17 MONITORED SINCE 2026-07-17

VERDICT

ranking generation 3

solid 79/100 #46 of 58 in Verification by measured score

What the score read on this service: status online, 99.7% uptime 30d, 3587ms response p95, x402 compliance 14 of 14, $0.02 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 58 listings, this one among them. That set is wider than the 58 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
10x402 strong 97 100% ---
Hermes Plant strong 96 100% ---
probe402 strong 96 100% ---
Permit Verdict Settlement Oracle strong 95 100% ---
Aegis strong 95 99.5% ---
5 of 57 other ranked services in Verification

ASSESSMENT

updated 50m 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 99.7%
uptime 24h
100%
uptime 7d
98.6%
uptime 30d
99.7%
uptime 90d
99.8%
response p95
3587ms
avg response
1596ms
total checks
2,775

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 $0.02 (p64 in Verification)
price (min)
$0.02
category percentile (min)
p64 in Verification
endpoints / prices
1 / 1
model
flat
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
44d
registrar
Cloudflare, Inc.
hosting
custom
domain created
2026-07-16

Identity facts, not a risk score.

traction $0.04 30d · 2 buyers
volume 30d
$0.04
buyers 30d
2
settlements 30d
2
measured since
2026-08-19 (start of our harvest window)
last settlement
2026-08-30
top buyer share
50% of 30d volume
trend 7d vs 30d
2.14x the 30d daily rate
networks
eip155:8453
volume all-time
$0.04
settlements all-time
2
median settlement 30d
$0.02
max settlement 30d
$0.02
settled via
coinbase ($0.04, 2 tx)

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.

CHANGES

1 in 30d

Payout, price, and schema changes detected on this service's x402 wire. A payout rotation at an unchanged price shows up here even when nothing else moves. Full feed at /changes.

changes schema changed 6d ago (1 in 30d)

schema changed · 6d ago

schema removed GET /v1/screen exact eip155:8453 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 USDC 2 300 {"name":"USD Coin","resource":"https://watchtower-api.com/v1/screen","version":"2"}

schema added GET /v1/screen exact eip155:8453 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 USDC 2 300 {"name":"USD Coin","resource":"https://justin-pacific-exchange-revelation.trycloudflare.com/v1/screen","version":"2"}

see all changes for this service

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 DESCRIPTION PRICE NETWORK ASSET 402 CHANNEL
GET /v1/screen $0.02 Base USDC header
1 endpoints

REQUEST / RESPONSE EXAMPLE

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

// request
curl -i 'https://watchtower-api.com/v1/screen'
// 402 response (captured by monitor) · 1 payload · click to expand
[
  {
    "error": "payment required",
    "accepts": [
      {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "extra": {
          "name": "USD Coin",
          "version": "2",
          "resource": "https://justin-pacific-exchange-revelation.trycloudflare.com/v1/screen"
        },
        "payTo": "0x8A060366289D1238F2bE62f3e462dDC7173b9ff2",
        "amount": "20000",
        "scheme": "exact",
        "network": "eip155:8453",
        "maxTimeoutSeconds": 300
      }
    ],
    "resource": {
      "url": "https://justin-pacific-exchange-revelation.trycloudflare.com/v1/screen",
      "tags": [
        "sanctions",
        "compliance",
        "screening",
        "aml"
      ],
      "mimeType": "application/json",
      "description": "Screen a person/company/vessel name against OFAC (SDN + Consolidated), UN, EU, UK, Canada, Australia, France, Switzerland, US export-control (BIS/State), and US SAM procurement/benefit exclusions. Deterministic typo-tolerant fuzzy matching with versioned list snapshots.",
      "serviceName": "Watchtower Sanctions Screening"
    },
    "extensions": {
      "bazaar": {
        "info": {
          "input": {
            "body": {
              "name": "Vladimir Putin"
            },
            "type": "http",
            "method": "POST",
            "bodyType": "json"
          },
          "output": {
            "type": "json",
            "example": {
              "match": true,
              "query": "Vladimir Putin",
              "matches": [
                {
                  "uid": "OFAC-SDN-36991",
                  "name": "PUTIN, Vladimir Vladimirovich",
                  "type": "person",
                  "score": 1,
                  "source": "OFAC-SDN",
                  "programs": [
                    "RUSSIA-EO14024"
                  ]
                }
              ],
              "algorithm": "wt-match-5",
              "snapshot_version": "53ae76305968fa31"
            }
          }
        },
        "name": "Sanctions Name Screening",
        "schema": {
          "type": "object",
          "$schema": "https://json-schema.org/draft/2020-12/schema",
          "required": [
            "input"
          ],
          "properties": {
            "input": {
              "type": "object",
              "required": [
                "type",
                "method",
                "bodyType",
                "body"
              ],
              "properties": {
                "body": {
                  "type": "object",
                  "required": [
                    "name"
                  ],
                  "properties": {
                    "dob": {
                      "type": "string",
                      "maxLength": 40,
                      "description": "Optional date of birth or birth year — excludes candidates whose known DOB contradicts it"
                    },
                    "name": {
                      "type": "string",
                      "maxLength": 500,
                      "minLength": 2,
                      "description": "Person, company, vessel, or aircraft name"
                    },
                    "limit": {
                      "type": "integer",
                      "maximum": 50,
                      "minimum": 1
                    },
                    "types": {
                      "type": "array",
                      "items": {
                        "enum": [
                          "person",
                          "entity",
                          "vessel",
                          "aircraft"
                        ]
                      }
                    },
                    "threshold": {
                      "type": "number",
                      "maximum": 1,
                      "minimum": 0.5
                    },
                    "nationality": {
                      "type": "string",
                      "maxLength": 60,
                      "description": "Optional nationality/country — excludes candidates whose known nationality contradicts it"
                    }
                  }
                },
                "type": {
                  "type": "string",
                  "const": "http"
                },
                "method": {
                  "enum": [
                    "POST"
                  ],
                  "type": "string"
                },
                "bodyType": {
                  "enum": [
                    "json"
                  ],
                  "type": "string"
                }
              }
            },
            "output": {
              "type": "object"
            }
          }
        },
        "category": "security",
        "description": "Screen names against OFAC + UN + EU + UK + Canada + Australia + France + Switzerland + US export-control + US SAM exclusions lists — deterministic fuzzy matching, pay per call via x402.",
        "discoverable": true
      }
    },
    "x402Version": 2
  }
]

OVER TIME

All charts use the 24h selector; each series spans only the dates it has data for. Every series is also served as JSON at /api/v1/services/watchtower/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
09-01 · uptime 100.0% · 2513ms avg09-0109-01
24h UPTIME 100%
RESPONSE TIME
09-01 · 2513ms avg09-01 · 2513ms avg09-0109-01
AVG RESP 1596ms
PRICE (captured 402, USD)
08-31 · $0.0209-01 · $0.02$0.0208-3109-01
SUB-SCORES (uptime + x402 compliance)
08-31 uptime: 99.7% compliance: 100% checks09-01 uptime: 99.7% compliance: 100% checksuptimecompliance08-3109-01

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

PILLARS OVER TIME (measured)

Measured site and economics pillars from the assessment history, so the latest value shown elsewhere on this page reads as a point on a trend rather than a permanent state.

VOLUME (on-chain settlement, USD)
no on-chain volume in the last 24h
DISTINCT BUYERS
no distinct buyers in the last 24h

COMPLIANCE

14/14 checks pass · grade A

last 402 captured 2026-08-25 · last up 2026-09-01

  • 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 (18) live · click to expand
TIME STATUS RESP CAUSE
● OK 983ms
● OK 1910ms
● SLOW 2575ms
● OK 1287ms
● SLOW 3678ms
● OK 622ms
● OK 2254ms
● OK 945ms
● OK 1321ms
● OK 1689ms
● OK 1898ms
● SLOW 2766ms
● SLOW 3164ms
● OK 2131ms
● SLOW 4384ms
● OK 2274ms
● OK 2274ms
● SLOW 4444ms

EMBED THIS BADGE

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

Watchtower listed on x402-list
status
Watchtower uptime on x402-list
live uptime
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// HTML · live uptime variant
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</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/watchtower/update.