x402 List

x402 Protocol Service Directory

SYNTHORA Mailcheck

Verification

Email address validation API. Returns RFC syntax check, live MX lookup, disposable and role account flags, free provider detection, gmail normalization, and a deliverability status with confidence score. No mail is sent. First 3 calls per wallet are free, then 0.001 USDC on Base.

Pay from $0.001 per request in USDC on Base, settled onchain via the x402 protocol, no signup, no API key needed.

UPTIME 24H 88.9% 7D 90% 30D 90%
BASE URL https://mailcheck.hergertsynthora.com ENDPOINTS 1 NETWORK Base ASSET USDC MEMBER SINCE 2026-07-20 MONITORED SINCE 2026-07-20

ASSESSMENT

updated 5h ago

Evidence-backed signals, not a single score. Click any chip for the proof. Measured values stay read-only; unknown is honest.

reliability 90.5%
uptime 24h
87.5%
uptime 7d
90.5%
uptime 30d
90.5%
uptime 90d
90.5%
response p95
4279ms
avg response
2006ms
total checks
24
compliance A (11/11)

11 of 11 x402 conformance checks pass. Full checklist below.

jump to compliance checklist

price $0.001 (p13 in Verification)
price (min)
$0.001
category percentile (min)
p13 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.

traction $0.03 30d · 0 buyers
volume 30d
$0.03
buyers 30d
0
settlements 30d
2
last settlement
2026-07-21
top buyer share
48% of 30d volume
trend 7d vs 30d
0.11x the 30d daily rate
networks
eip155:8453

Attributed pro-quota: this payout address is shared, so volume and buyers are the operator-level figure divided by the services sharing it. A declared convention, not an individually observed measure, and still a conservative undercount.

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

WHAT IT DOES

ai-derived

Verifies whether an email address is real and safe to send to by checking RFC syntax, MX records, disposable domains, role accounts, free providers, and common typos.

category
email-validation
in
body
auth
api key
email-validationverificationmx-checkdisposable-domain-detectionrole-account-detectionemail-enrichment

AI-generated summary. The measured data is never altered by it.

ENDPOINTS

Service endpoints with HTTP method, path, description, pricing, and network
METHOD PATH DESCRIPTION PRICE NETWORK ASSET
POST /service Verify whether an email address is real and safe to send to. Checks RFC syntax, live MX records, catch-all and disposable/temporary domains, role accounts (info@, admin@), free providers and common typos, returning a deliverability status and confidence score. Use it to validate and enrich contacts, clean email lists and prevent bounces. Deterministic, Ed25519-signed. 0.001 USDC on Base. First 3 calls FREE per wallet — send header 'X-WALLET: 0x<your Base address>' (no payment); then per call. $0.001 Base USDC
1 endpoints

REQUEST / RESPONSE EXAMPLE

An unpaid request to POST /service 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://mailcheck.hergertsynthora.com/service'
// 402 response (captured by monitor) · 1 payload · click to expand
[
  {
    "error": "Payment required",
    "accepts": [
      {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "extra": {
          "name": "USD Coin",
          "version": "2"
        },
        "payTo": "0x10800a5a5B9d72251566EC651E862A8b4B427dE0",
        "amount": "1000",
        "scheme": "exact",
        "network": "eip155:8453",
        "mimeType": "application/json",
        "resource": "https://mailcheck.hergertsynthora.com/service",
        "description": "Verify whether an email address is real and safe to send to. Checks RFC syntax, live MX records, catch-all and disposable/temporary domains, role accounts (info@, admin@), free providers and common typos, returning a deliverability status and confidence score. Use it to validate and enrich contacts, clean email lists and prevent bounces. Deterministic, Ed25519-signed. 0.001 USDC on Base. First 3 calls FREE per wallet — send header 'X-WALLET: 0x<your Base address>' (no payment); then  per call.",
        "maxAmountRequired": "1000",
        "maxTimeoutSeconds": 300
      }
    ],
    "freeTier": {
      "note": "send header X-WALLET: 0x<your Base address> for a free trial",
      "header": "X-WALLET",
      "callsPerWallet": 3
    },
    "resource": {
      "url": "https://mailcheck.hergertsynthora.com/service",
      "mimeType": "application/json",
      "description": "Verify whether an email address is real and safe to send to. Checks RFC syntax, live MX records, catch-all and disposable/temporary domains, role accounts (info@, admin@), free providers and common typos, returning a deliverability status and confidence score. Use it to validate and enrich contacts, clean email lists and prevent bounces. Deterministic, Ed25519-signed. 0.001 USDC on Base. First 3 calls FREE per wallet — send header 'X-WALLET: 0x<your Base address>' (no payment); then  per call."
    },
    "extensions": {
      "bazaar": {
        "info": {
          "input": {
            "body": {
              "email": "[email protected]"
            },
            "type": "http",
            "method": "POST",
            "bodyType": "json"
          },
          "output": {
            "type": "json",
            "example": {
              "ok": true,
              "niche": "mailcheck",
              "result": {
                "email": "[email protected]",
                "status": "deliverable",
                "mx_found": true,
                "confidence": 90,
                "deliverable_hint": true
              }
            }
          }
        },
        "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": [
                    "email"
                  ],
                  "properties": {
                    "email": {
                      "type": "string",
                      "description": "Email address to verify"
                    }
                  }
                },
                "type": {
                  "type": "string",
                  "const": "http"
                },
                "method": {
                  "enum": [
                    "POST",
                    "PUT",
                    "PATCH"
                  ],
                  "type": "string"
                },
                "bodyType": {
                  "enum": [
                    "json",
                    "form-data",
                    "text"
                  ],
                  "type": "string"
                }
              },
              "additionalProperties": false
            },
            "output": {
              "type": "object",
              "required": [
                "type"
              ],
              "properties": {
                "type": {
                  "type": "string"
                },
                "example": {
                  "ok": {
                    "type": "boolean"
                  },
                  "type": "object",
                  "niche": {
                    "type": "string"
                  }
                }
              }
            }
          }
        }
      }
    },
    "x402Version": 2
  }
]

UPTIME

07-20 · uptime 92.3% · 2520ms avg07-21 · uptime 88.9% · 1842ms avg07-20 · uptime 92.3% · 2520ms avg07-21 · uptime 88.9% · 1842ms avg07-2007-21
RESPONSE TIME
07-20 · 2520ms avg07-20 · 2520ms avg07-21 · 1842ms avg07-21 · 1842ms avg07-2007-21
30d UPTIME 90%
UPTIME 30D 90%
AVG RESP 2035ms
TOTAL CHECKS 41

RECENT CHECKS

TIME STATUS RESP
● OK 860ms
○ DOWN 10000ms
● OK 2345ms
● OK 1463ms
● OK 657ms
● OK 1354ms
● OK 1162ms
● OK 1930ms
● OK 2893ms
● SLOW 3453ms
● OK 2273ms
● OK 1729ms
● SLOW 4195ms
● OK 760ms
● SLOW 4838ms
● OK 1267ms
○ DOWN 10001ms
● OK 1099ms

OVER TIME

All charts share the 30d window selected here. Every series is also served as JSON at /api/v1/services/synthora-mailcheck/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).

PRICE (captured 402, USD)
07-20 · $0.00107-21 · $0.001$0.00107-2007-21
SUB-SCORES (uptime + x402 compliance)
07-20 compliance: 100% checks07-21 uptime: 90.5% compliance: 100% checksuptimecompliance07-2007-21
VOLUME (on-chain settlement, USD)
06-29 · $0.0706-30 · $0.5807-01 · $0.1007-02 · $0.0107-03 · $0.0107-04 · $0.0107-05 · $0.0007-06 · $0.0307-07 · $0.2107-08 · $0.6007-09 · $0.0207-15 · $0.0007-16 · $0.0107-18 · $0.0207-19 · $0.0007-20 · $0.0107-21 · $0.00peak $0.6006-2907-21

Shared payout address (61 other services). These bars are the full shared address (operator-level), so do not sum them across the services that share it. Where a per-service figure is attributed, the assessment block and the ranking, it is the address total divided pro-quota by the 62 services sharing it: a declared convention, not an individually observed measure.

DISTINCT BUYERS
06-29 · 1 buyer06-30 · 1 buyer07-01 · 1 buyer07-02 · 1 buyer07-03 · 1 buyer07-04 · 1 buyer07-05 · 1 buyer07-06 · 3 buyers07-07 · 3 buyers07-08 · 5 buyers07-09 · 3 buyers07-15 · 3 buyers07-16 · 2 buyers07-18 · 2 buyers07-19 · 1 buyer07-20 · 2 buyers07-21 · 1 buyerpeak 5 buyers06-2907-21

Shared payout address (61 other services). These bars are the full shared address (operator-level), so do not sum them across the services that share it. Where a per-service buyer count is attributed, the assessment block and the ranking, it is divided pro-quota by the 62 services sharing the address and can be fractional: a declared convention, not an individually observed measure.

COMPLIANCE

11/11 checks pass · grade A
  • 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

EMBED THIS BADGE

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

SYNTHORA Mailcheck listed on x402-list
status
SYNTHORA Mailcheck uptime on x402-list
live uptime
// HTML
<a href="https://x402-list.com/services/synthora-mailcheck?utm_source=badge&utm_medium=referral&utm_campaign=embed">
  <img src="https://x402-list.com/badge/synthora-mailcheck.svg" alt="SYNTHORA Mailcheck listed on x402-list" height="28">
</a>
// Markdown
[![SYNTHORA Mailcheck on x402-list](https://x402-list.com/badge/synthora-mailcheck.svg)](https://x402-list.com/services/synthora-mailcheck?utm_source=badge&utm_medium=referral&utm_campaign=embed)
// HTML · live uptime variant
<a href="https://x402-list.com/services/synthora-mailcheck?utm_source=badge&utm_medium=referral&utm_campaign=embed">
  <img src="https://x402-list.com/badge/synthora-mailcheck.svg?data=uptime" alt="SYNTHORA Mailcheck uptime on x402-list" height="28">
</a>

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