●

SendCheck

Verification PAYMENT-READY

payment-ready until 2026-10-06

Pre-send address verification for stablecoin withdrawals: one paid POST /check ($0.01) parses address + token contract, probes live RPCs and exchanges, and returns a warn-level verdict before you send USDC. POST /deep ($0.05) adds extended checks.

Pay from $0.01 to $0.05 per request in USDC on Base, settled onchain via the x402 protocol, no signup, no API key needed.

measured since 2026-09-03 (start of our harvest window) · $0.58 all-time · settled via coinbase, payAI

BASE URL https://api.pennyforge.org │ WEBSITE https://sendcheck.surge.sh │ ENDPOINTS 2 │ NETWORK Base │ ASSET USDC │ MEMBER SINCE 2026-09-07 │ MONITORED SINCE 2026-09-07

VERDICT

ranking generation 3

solid 85/100 #32 of 113 in Verification by measured score

What the score read on this service: status online, 99.5% uptime 30d, 987ms 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 113 listings, this one among them. That set is wider than the 113 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	94	100%	$918.33
Rubric Protocol — Post-Quantum AI Attestation	solid	93	99.8%	$33.21
Enclave402	solid	89	100%	$3.98
LION — Verified Company & Compliance Data	solid	89	100%	$5.80
767-2676.com - POPCORN	solid	89	100%	$0.11

5 of 112 other ranked services in Verification

ASSESSMENT

updated 6h 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 99.5%

uptime · latest daily rollup: 100%
uptime 7d: 100%
uptime 30d: 99.5%
uptime 90d: 99.5%
response p95: 987ms
avg response: 489ms
total checks: 1,941

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 $0.05 (p44 in Verification)

price (min): $0.01
price (max): $0.05
category percentile (min): p44 in Verification
category percentile (max): p45 in Verification
endpoints / prices: 2 / 2
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: -
registrar: -
hosting: free host
domain created: ---

Identity facts, not a risk score.

traction $0.28 30d · 9 buyers

volume 30d: $0.28
buyers 30d: 9
settlements 30d: 24
measured since: 2026-09-03 (start of our harvest window)
last settlement: 2026-09-28
top buyer share: 29% of 30d volume (address, not entity)
trend 7d vs 30d: 1.22x the 30d daily rate
networks: eip155:8453
volume all-time: $0.58
settlements all-time: 51
median settlement 30d: $0.01
max settlement 30d: $0.05
settled via: coinbase ($0.27, 23 tx), payAI ($0.01, 1 tx)

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

Top buyer share is part of the ranking score: a higher share lowers the traction part of the score, by up to half when one address holds all 30d volume.

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
POST	/check		$0.01	Base	USDC	header
POST	/deep		$0.05	Base	USDC	header

2 endpoints

REQUEST / RESPONSE EXAMPLE

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

// request

curl -i -X POST 'https://api.pennyforge.org/check'

// 402 response (captured by monitor) · 2 payloads · click to expand

[
  {
    "error": "Payment required",
    "accepts": [
      {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "extra": {
          "name": "USD Coin",
          "version": "2"
        },
        "payTo": "0x9504A5939AB5be2B2B1F8beA7D7ebeCcd96c485D",
        "amount": "10000",
        "scheme": "exact",
        "network": "eip155:8453",
        "maxTimeoutSeconds": 60
      }
    ],
    "resource": {
      "url": "https://sendcheck-x402.pennyforge.workers.dev/check",
      "tags": [
        "evm",
        "crypto",
        "security",
        "usdc",
        "address-verification"
      ],
      "mimeType": "application/json",
      "description": "SendCheck: pre-send verification of any EVM address on one chain (EIP-55 checksum, wallet-vs-contract, outgoing activity, balances, verdict). POST {address, chain}",
      "serviceName": "sendcheck"
    },
    "extensions": {
      "bazaar": {
        "info": {
          "input": {
            "body": {
              "chain": "base",
              "address": "0x9504A5939AB5be2B2B1F8beA7D7ebeCcd96c485D"
            },
            "type": "http",
            "method": "POST",
            "bodyType": "json"
          },
          "output": {
            "type": "json",
            "example": {
              "meta": {
                "ms": 912,
                "service": "sendcheck",
                "version": "1.8.1"
              },
              "chain": {
                "name": "Base",
                "usdc": "30.23",
                "usdt": "0.00",
                "block": 50804109,
                "chain": 8453,
                "native": "0.0026",
                "reachable": true,
                "usdcUnits": "30230079",
                "usdtUnits": "0",
                "isContract": false,
                "outgoingTxs": 3
              },
              "report": "SendCheck pre-send verification …",
              "address": "0x9504A5939AB5be2B2B1F8beA7D7ebeCcd96c485D",
              "verdict": {
                "gas": "0.00000039 ETH",
                "next": "Verify the recipient out-of-band before sending.",
                "level": "caution",
                "reasons": [
                  "…"
                ],
                "headline": "Live wallet with recent activity.",
                "tokenMismatch": null
              },
              "checksum": {
                "status": "valid",
                "message": "Valid EIP-55 checksum address."
              }
            }
          }
        },
        "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": [
                    "address"
                  ],
                  "properties": {
                    "chain": {
                      "enum": [
                        "base",
                        "ethereum",
                        "arbitrum",
                        "optimism",
                        "polygon"
                      ],
                      "type": "string",
                      "description": "Chain to scan (default: base)"
                    },
                    "address": {
                      "type": "string",
                      "description": "EVM address to verify, 0x + 40 hex characters. Free format pre-check: GET /validate?address=…"
                    }
                  }
                },
                "type": {
                  "type": "string",
                  "const": "http"
                },
                "method": {
                  "enum": [
                    "POST"
                  ],
                  "type": "string"
                },
                "bodyType": {
                  "enum": [
                    "json"
                  ],
                  "type": "string"
                }
              },
              "additionalProperties": false
            },
            "output": {
              "type": "object",
              "required": [
                "type"
              ],
              "properties": {
                "type": {
                  "type": "string"
                },
                "example": {
                  "type": "object"
                }
              }
            }
          }
        }
      },
      "x-sendcheck-attestation": {
        "jws": "eyJhbGciOiJFUzI1NiIsImtpZCI6InNlbmRjaGVjay0yMDI2LTA5In0.eyJhc3NldCI6IjB4ODMzNTg5ZkNENmVEYjZFMDhmNGM3QzMyRDRmNzFiNTRiZEEwMjkxMyIsImV4cCI6MTgyMDI3NTgyMywiaWF0IjoxNzg4NzM5ODIzLCJuZXR3b3JrIjoiZWlwMTU1Ojg0NTMiLCJwYXlUbyI6IjB4OTUwNEE1OTM5QUI1YmUyQjJCMUY4YmVBN0Q3ZWJlQ2NkOTZjNDg1RCIsInJvdXRlcyI6W3sibWF4UHJpY2UiOiIwLjAxIiwicmVzb3VyY2UiOiIvY2hlY2sifSx7Im1heFByaWNlIjoiMC4wNSIsInJlc291cmNlIjoiL2RlZXAifV0sInNlcnZpY2UiOiJodHRwczovL3NlbmRjaGVjay14NDAyLnBlbm55Zm9yZ2Uud29ya2Vycy5kZXYiLCJ2IjoxfQ.sFhM75UvF2ZlPRxZunHetZnz0_p_RoTHNZt7M84Ox0vRCea2ho98Ai2qFOT1kqTeibmhbcWYcAwjQS-QdlVEeg",
        "key": {
          "x": "byHMSJi37KTtQRTkxSj1dNRUppDNKCMqj_W7dfC45Us",
          "y": "mTV7jNFab5gU3P77chUHrdbnm3pegzrOjWdLXL3WRvs",
          "alg": "ES256",
          "crv": "P-256",
          "kid": "sendcheck-2026-09",
          "kty": "EC",
          "use": "sig"
        },
        "info": {
          "input": {
            "body": {
              "chain": "base",
              "address": "0x9504A5939AB5be2B2B1F8beA7D7ebeCcd96c485D"
            },
            "type": "http",
            "method": "POST",
            "bodyType": "json"
          },
          "output": {
            "type": "json",
            "example": {
              "jws": "<ES256 JWS compact: b64url(header).b64url(canonical-JSON payload).b64url(64-byte signature)>",
              "key": {
                "x": "<base64url P-256 X>",
                "y": "<base64url P-256 Y>",
                "crv": "P-256",
                "kid": "sendcheck-2026-09",
                "kty": "EC"
              }
            }
          }
        },
        "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": [
                    "address"
                  ],
                  "properties": {
                    "chain": {
                      "enum": [
                        "base",
                        "ethereum",
                        "arbitrum",
                        "optimism",
                        "polygon"
                      ],
                      "type": "string",
                      "description": "Chain to scan (default: base)"
                    },
                    "address": {
                      "type": "string",
                      "description": "EVM address to verify, 0x + 40 hex characters. Free format pre-check: GET /validate?address=…"
                    }
                  }
                },
                "type": {
                  "type": "string",
                  "const": "http"
                },
                "method": {
                  "enum": [
                    "POST"
                  ],
                  "type": "string"
                },
                "bodyType": {
                  "enum": [
                    "json"
                  ],
                  "type": "string"
                }
              },
              "additionalProperties": false
            },
            "output": {
              "type": "object",
              "required": [
                "type"
              ],
              "properties": {
                "type": {
                  "type": "string"
                },
                "example": {
                  "type": "object"
                }
              }
            }
          }
        }
      }
    },
    "x402Version": 2
  },
  {
    "error": "Payment required",
    "accepts": [
      {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "extra": {
          "name": "USD Coin",
          "version": "2"
        },
        "payTo": "0x9504A5939AB5be2B2B1F8beA7D7ebeCcd96c485D",
        "amount": "50000",
        "scheme": "exact",
        "network": "eip155:8453",
        "maxTimeoutSeconds": 60
      }
    ],
    "resource": {
      "url": "https://sendcheck-x402.pennyforge.workers.dev/deep",
      "tags": [
        "evm",
        "crypto",
        "security",
        "usdc",
        "address-verification"
      ],
      "mimeType": "application/json",
      "description": "SendCheck deep scan: the same verification across all 5 chains (Base, Ethereum, Arbitrum, Optimism, Polygon) incl. wrong-network detection. POST {address, chain}",
      "serviceName": "sendcheck"
    },
    "extensions": {
      "bazaar": {
        "info": {
          "input": {
            "body": {
              "chain": "base",
              "address": "0x9504A5939AB5be2B2B1F8beA7D7ebeCcd96c485D"
            },
            "type": "http",
            "method": "POST",
            "bodyType": "json"
          },
          "output": {
            "type": "json",
            "example": {
              "meta": {
                "ms": 2140,
                "service": "sendcheck",
                "version": "1.8.1"
              },
              "chain": {
                "name": "Base",
                "usdc": "30.23",
                "usdt": "0.00",
                "block": 50804109,
                "chain": 8453,
                "native": "0.0026",
                "reachable": true,
                "usdcUnits": "30230079",
                "usdtUnits": "0",
                "isContract": false,
                "outgoingTxs": 3
              },
              "others": [
                {
                  "name": "Ethereum",
                  "usdc": "0.00",
                  "usdt": "0.00",
                  "chain": 1,
                  "native": "0.0",
                  "reachable": true,
                  "isContract": false,
                  "outgoingTxs": 12
                }
              ],
              "report": "SendCheck deep scan …",
              "address": "0x9504A5939AB5be2B2B1F8beA7D7ebeCcd96c485D",
              "verdict": {
                "gas": "0.00000039 ETH",
                "next": "Confirm you truly mean Base before sending.",
                "level": "warn",
                "reasons": [
                  "…"
                ],
                "headline": "Address is more active on Ethereum than on Base.",
                "tokenMismatch": null
              },
              "checksum": {
                "status": "valid",
                "message": "Valid EIP-55 checksum address."
              }
            }
          }
        },
        "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": [
                    "address"
                  ],
                  "properties": {
                    "chain": {
                      "enum": [
                        "base",
                        "ethereum",
                        "arbitrum",
                        "optimism",
                        "polygon"
                      ],
                      "type": "string",
                      "description": "Chain to scan (default: base)"
                    },
                    "address": {
                      "type": "string",
                      "description": "EVM address to verify, 0x + 40 hex characters. Free format pre-check: GET /validate?address=…"
                    }
                  }
                },
                "type": {
                  "type": "string",
                  "const": "http"
                },
                "method": {
                  "enum": [
                    "POST"
                  ],
                  "type": "string"
                },
                "bodyType": {
                  "enum": [
                    "json"
                  ],
                  "type": "string"
                }
              },
              "additionalProperties": false
            },
            "output": {
              "type": "object",
              "required": [
                "type"
              ],
              "properties": {
                "type": {
                  "type": "string"
                },
                "example": {
                  "type": "object"
                }
              }
            }
          }
        }
      },
      "x-sendcheck-attestation": {
        "jws": "eyJhbGciOiJFUzI1NiIsImtpZCI6InNlbmRjaGVjay0yMDI2LTA5In0.eyJhc3NldCI6IjB4ODMzNTg5ZkNENmVEYjZFMDhmNGM3QzMyRDRmNzFiNTRiZEEwMjkxMyIsImV4cCI6MTgyMDI3NTgyMywiaWF0IjoxNzg4NzM5ODIzLCJuZXR3b3JrIjoiZWlwMTU1Ojg0NTMiLCJwYXlUbyI6IjB4OTUwNEE1OTM5QUI1YmUyQjJCMUY4YmVBN0Q3ZWJlQ2NkOTZjNDg1RCIsInJvdXRlcyI6W3sibWF4UHJpY2UiOiIwLjAxIiwicmVzb3VyY2UiOiIvY2hlY2sifSx7Im1heFByaWNlIjoiMC4wNSIsInJlc291cmNlIjoiL2RlZXAifV0sInNlcnZpY2UiOiJodHRwczovL3NlbmRjaGVjay14NDAyLnBlbm55Zm9yZ2Uud29ya2Vycy5kZXYiLCJ2IjoxfQ.sFhM75UvF2ZlPRxZunHetZnz0_p_RoTHNZt7M84Ox0vRCea2ho98Ai2qFOT1kqTeibmhbcWYcAwjQS-QdlVEeg",
        "key": {
          "x": "byHMSJi37KTtQRTkxSj1dNRUppDNKCMqj_W7dfC45Us",
          "y": "mTV7jNFab5gU3P77chUHrdbnm3pegzrOjWdLXL3WRvs",
          "alg": "ES256",
          "crv": "P-256",
          "kid": "sendcheck-2026-09",
          "kty": "EC",
          "use": "sig"
        },
        "info": {
          "input": {
            "body": {
              "chain": "base",
              "address": "0x9504A5939AB5be2B2B1F8beA7D7ebeCcd96c485D"
            },
            "type": "http",
            "method": "POST",
            "bodyType": "json"
          },
          "output": {
            "type": "json",
            "example": {
              "jws": "<ES256 JWS compact: b64url(header).b64url(canonical-JSON payload).b64url(64-byte signature)>",
              "key": {
                "x": "<base64url P-256 X>",
                "y": "<base64url P-256 Y>",
                "crv": "P-256",
                "kid": "sendcheck-2026-09",
                "kty": "EC"
              }
            }
          }
        },
        "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": [
                    "address"
                  ],
                  "properties": {
                    "chain": {
                      "enum": [
                        "base",
                        "ethereum",
                        "arbitrum",
                        "optimism",
                        "polygon"
                      ],
                      "type": "string",
                      "description": "Chain to scan (default: base)"
                    },
                    "address": {
                      "type": "string",
                      "description": "EVM address to verify, 0x + 40 hex characters. Free format pre-check: GET /validate?address=…"
                    }
                  }
                },
                "type": {
                  "type": "string",
                  "const": "http"
                },
                "method": {
                  "enum": [
                    "POST"
                  ],
                  "type": "string"
                },
                "bodyType": {
                  "enum": [
                    "json"
                  ],
                  "type": "string"
                }
              },
              "additionalProperties": false
            },
            "output": {
              "type": "object",
              "required": [
                "type"
              ],
              "properties": {
                "type": {
                  "type": "string"
                },
                "example": {
                  "type": "object"
                }
              }
            }
          }
        }
      }
    },
    "x402Version": 2
  }
]

OVER TIME

All charts use the 30d selector; each series spans only the dates it has data for. Every series is also served as JSON at /api/v1/services/sendcheck/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

30D UPTIME 99.5%

RESPONSE TIME

AVG RESP 488ms

PRICE (captured 402, USD)

Median across 2 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

PILLARS OVER TIME (measured)

price percentile in Verification

site signals present (of 6)

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)

DISTINCT BUYERS

COMPLIANCE

14/14 checks pass · grade A

last 402 captured 2026-09-07 · last up 2026-09-29

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

04:17:24 UTC ● OK 522ms

04:01:25 UTC ● OK 514ms

03:45:22 UTC ● OK 724ms

03:29:23 UTC ● OK 388ms

03:13:23 UTC ● OK 347ms

02:57:21 UTC ● OK 337ms

02:41:21 UTC ● OK 76ms

02:25:23 UTC ● OK 333ms

02:09:19 UTC ● OK 570ms

01:53:24 UTC ● OK 247ms

01:37:20 UTC ● OK 563ms

01:21:22 UTC ● OK 302ms

01:05:23 UTC ● OK 265ms

00:49:24 UTC ● OK 598ms

00:33:18 UTC ● OK 407ms

00:17:19 UTC ● OK 291ms

00:01:21 UTC ● OK 317ms

23:45:21 UTC ● OK 330ms

EMBED THIS BADGE

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

status

SendCheck uptime on x402-list — live uptime

// HTML

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

// Markdown

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

// HTML · live uptime variant

<a href="https://x402-list.com/services/sendcheck?utm_source=badge&utm_medium=referral&utm_campaign=embed">
  <img src="https://x402-list.com/badge/sendcheck.svg?data=uptime" alt="SendCheck 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/sendcheck/update.