Blockchain Data · x402

Email validation API: RFC-style syntax check plus live MX-record lookup (with RFC 5321…

by gateway.stride20k.com · discovered, not yet claimed by its owner · updated 2026-08-20

Not responding. This endpoint did not answer its last liveness check (2026-10-13). It may be temporarily down.

Mirrored from Coinbase's public x402 Bazaar. The description is the provider's own text and has not been reviewed here; the payment requirements are copied as published.

What it does

Email validation API: RFC-style syntax check plus live MX-record lookup (with RFC 5321 A-record fallback) over DNS-over-HTTPS — no third-party service, nothing stored. Returns parsed domain, sorted MX hosts, and a 'deliverable' flag meaning DNS will accept mail for the domain — it does NOT verify the mailbox exists. Use for lead cleaning, signup validation, and contact verification by agents. Cached up to 1 hour per address.

Tags: bazaar

Use with an agent

Discover. Agents find this listing with GET https://bazaar.saylorinnovations.com/discovery/search?query=…, the MCP tool search_resources, or /discovery/resources.
Inspect. Fetch /resources/1168.json for the price and payment options.
Pay. Call GET https://gateway.stride20k.com/email/validate/:email. The provider answers 402 with its payment requirements. An x402 client signs one of the options below and retries with PAYMENT-SIGNATURE.
Execute. The provider returns 200 with the data. Agent Bazaar is not in the request path and never sees your payment.

For humans

You don't need an account or an API key; you need a wallet holding a small amount of USDC on Base, and an x402-capable client (see the examples below). Call the endpoint unpaid first to see exactly what it asks for.

Pricing & payment

Price: $0.005 / request
Protocol: x402 v2
Auth: No account or API key. Pay per request.
Networks: Base
Uptime: 0 of the last 1 checks answered
Calls (30d): 1 · 1 unique payers (third-party data from the public x402 Bazaar)

x402 payment requirements

Scheme	Network	Asset	Amount	Pay to	Timeout
exact	Base eip155:8453	USDC	$0.005	0xAbe512E06dddC82581d2E5a19Ab594E778490441	60s

accepts[] (raw JSON)

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0xAbe512E06dddC82581d2E5a19Ab594E778490441",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "5000",
    "amountUsd": 0.005,
    "maxTimeoutSeconds": 60
  }
]

Schemas

Output schema (JSON Schema)

{
  "bazaar": {
    "info": {
      "input": {
        "method": "GET",
        "pathParams": {
          "email": "postmaster%40example.com"
        },
        "queryParams": {},
        "type": "http"
      },
      "output": {
        "example": {
          "data": {
            "aFallback": false,
            "deliverable": true,
            "domain": "example.com",
            "email": "[email protected]",
            "hasMx": true,
            "mx": [
              {
                "exchange": "mail.example.com",
                "preference": 10
              }
            ],
            "syntaxValid": true
          },
          "endpoint": "/email/validate/:email",
          "meta": {
            "attribution": null,
            "cached": false,
            "fetchedAt": "2026-07-04T00:00:00.000Z",
            "source": "local + Cloudflare DoH"
          },
          "ok": true
        },
        "type": "json"
      }
    },
    "routeTemplate": "/email/validate/:email",
    "schema": {
      "$schema": "https://json-schema.org/draft/2020-12/schema",
      "properties": {
        "input": {
          "additionalProperties": false,
          "properties": {
            "method": {
              "enum": [
                "GET"
              ],
              "type": "string"
            },
            "pathParams": {
              "properties": {
                "email": {
                  "description": "Email address to validate.",
                  "type": "string"
                }
              },
              "required": [
                "email"
              ],
              "type": "object"
            },
            "queryParams": {
              "properties": {},
              "type": "object"
            },
            "type": {
              "const": "http",
              "type": "string"
            }
          },
          "required": [
            "type",
            "method"
          ],
          "type": "object"
        },
        "output": {
          "properties": {
            "example": {
              "properties": {
                "data": {
                  "properties": {
                    "aFallback": {
                      "description": "True if no MX but the domain has an A record (RFC 5321 fallback).",
                      "type": "boolean"
                    },
                    "deliverable": {
                      "description": "hasMx OR aFallback. Not a mailbox-existence check.",
                      "type": "boolean"
                    },
                    "domain": {
                      "description": "Parsed domain part, lowercase, or null if syntax-invalid.",
                      "type": "string"
                    },
                    "email": {
                      "description": "The address as received.",
                      "type": "string"
                    },
                    "hasMx": {
                      "description": "Whether the domain publishes MX records.",
                      "type": "boolean"
                    },
                    "mx": {
                      "description": "MX records sorted by preference: { preference, exchange }.",
                      "type": "array"
                    },
                    "syntaxValid": {
                      "description": "Whether the address passes syntax validation.",
                      "type": "boolean"
                    }
                  },
                  "required": [
                    "email",
                    "syntaxValid",
                    "deliverable"
                  ],
                  "type": "object"
                },
                "endpoint": {
                  "description": "Always \"/email/validate/:email\".",
                  "type": "string"
                },
                "meta": {
                  "properties": {
                    "attribution": {
                      "description": "Licensing attribution when the source requires it.",
                      "type": [
                        "string",
                        "null"
                      ]
                    },
                    "cached": {
                      "description": "Whether this response was served from cache.",
                      "type": "boolean"
                    },
                    "fetchedAt": {
                      "description": "ISO 8601 time the data was actually retrieved from the upstream.",
                      "type": "string"
                    },
                    "source": {
                      "description": "Upstream source: local + Cloudflare DoH.",
                      "type": "string"
                    }
                  },
                  "required": [
                    "source",
                    "cached",
                    "fetchedAt"
                  ],
                  "type": "object"
                },
                "ok": {
                  "description": "true on success.",
                  "type": "boolean"
                }
              },
              "required": [
                "ok",
                "endpoint",
                "data",
                "meta"
              ],
              "type": "object"
            },
            "type": {
              "type": "string"
            }
          },
          "required": [
            "type"
          ],
          "type": "object"
        }
      },
      "required": [
        "input"
      ],
      "type": "object"
    }
  }
}

Example shape — generated from the schema, not a captured live response

null

Examples

curl

curl "https://gateway.stride20k.com/email/validate/:email"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid

JavaScript

const res = await fetch("https://gateway.stride20k.com/email/validate/:email");
if (res.status === 402) {
  const { accepts } = await res.json();
  // pay one of accepts[] via an x402 client, then retry with the payment header
}

Python

import httpx
res = httpx.get("https://gateway.stride20k.com/email/validate/:email")
if res.status_code == 402:
    accepts = res.json()["accepts"]
    # pay one of accepts[] via an x402 client, then retry with the payment header

Details

Provider: gateway.stride20k.com
Endpoint: https://gateway.stride20k.com/email/validate/:email
Machine-readable: /resources/1168.json