Factline
Use when you need to know if an email address is real and deliverable before signup, outreach or onboarding: syntax, live MX routing, 9,000+ disposable domains, role addresses, free providers, typo suggestions (gmial.com to gmail.com) and SPF/DMARC. One verdict: deliverable, risky or undeliverable.
The wallet the 402 directs payment to. Its whole payment record — every payer, every chain — is on the merchant page.
Asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
The payTo wallet does not resolve to a registered ERC-8004 agent. That is not a verdict on the service — most of the catalog is unregistered.
Live 402 challenge
Captured by the enrichment pass, not read just now. Prices can change — always read the 402 the endpoint answers with.
{
"docs": "/llms.txt",
"error": "payment_required",
"message": "This costs 0.002 USDC via x402. Payment details are in the PAYMENT-REQUIRED header.",
"preview": "https://factline.dev/v1/email/verify/preview",
"price_usdc": "0.002",
"preview_hint": "Free: call the preview with the same query parameters to check your input and see what the paid answer contains before paying."
}Accepts
The payment requirements as published to the catalog. Read the live 402 before paying — a price here is a claim, not a quote.
Pay 0.002 USDC on Base to 0xb58d…b2075. The signed payment is good for 2 minutes.
- Paid to
- 0xb58d…b2075
- USD Coin contract
- 0x8335…02913
- Payment window
- 2 minutes
- As published
- 2000 smallest units
That figure is in the token’s smallest units. Roundhouse does not hold this contract’s decimals, so it is shown as published rather than converted.
- Paid to
- fyqifu…inMTK
- Token contract
- EPjFWd…TDt1v
- Payment window
- 2 minutes
The catalog’s raw entry
[
{
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"extra": {
"name": "USD Coin",
"version": "2"
},
"payTo": "0xb58dd178abac67f6d4894437a7fc725cbddb2075",
"amount": "2000",
"scheme": "exact",
"network": "eip155:8453",
"maxTimeoutSeconds": 120
},
{
"asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
"extra": {
"feePayer": "GVJJ7rdGiXr5xaYbRwRbjfaJL7fmwRygFi1H6aGqDveb"
},
"payTo": "fyqifu7otDYanhqr84B9YzZfA5LwRTJ1uFLqDJinMTK",
"amount": "2000",
"scheme": "exact",
"network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
"maxTimeoutSeconds": 120
}
]Extensions
{
"bazaar": {
"info": {
"input": {
"type": "http",
"method": "GET",
"queryParams": {
"email": "jan.jansen@gmial.com"
}
},
"output": {
"type": "json",
"example": {
"email": "jan.jansen@gmial.com",
"domain": "gmial.com",
"source": "DNS via Cloudflare 1.1.1.1 (DNS-over-HTTPS); disposable-email-domains (CC0)",
"explain": {
"limits": "No SMTP mailbox probe: this confirms the domain can receive mail, not that this exact mailbox exists.",
"verdict": "deliverable: domain receives mail and nothing suspicious; deliverable_role: same but a shared inbox; risky: disposable domain or likely typo; undeliverable: bad syntax or the domain cannot receive mail.",
"disposable_list": "disposable-email-domains blocklist (CC0), 2026-10-07"
},
"reasons": [
"disposable (throwaway) email domain",
"possible typo of gmail.com"
],
"verdict": "risky",
"disposable": true,
"suggestion": "jan.jansen@gmail.com",
"mail_routing": {
"mx": [],
"null_mx": false,
"implicit_mx": true,
"accepts_mail": true,
"domain_exists": true
},
"role_account": false,
"syntax_valid": true,
"free_provider": false,
"domain_security": {
"spf": false,
"dmarc_policy": null
}
}
}
},
"schema": {
"type": "object",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"required": [
"input"
],
"properties": {
"input": {
"type": "object",
"required": [
"type",
"method"
],
"properties": {
"type": {
"type": "string",
"const": "http"
},
"method": {
"enum": [
"GET"
],
"type": "string"
},
"queryParams": {
"type": "object",
"required": [
"email"
],
"properties": {
"email": {
"type": "string",
"description": "Email address to verify, e.g. jan.jansen@example.nl"
}
}
}
},
"additionalProperties": false
},
"output": {
"type": "object",
"required": [
"type"
],
"properties": {
"type": {
"type": "string"
},
"example": {
"type": "object"
}
}
}
}
}
},
"payment-identifier": {
"info": {
"required": false
},
"schema": {
"type": "object",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"required": [
"required"
],
"properties": {
"id": {
"type": "string",
"pattern": "^[a-zA-Z0-9_-]+$",
"maxLength": 128,
"minLength": 16
},
"required": {
"type": "boolean"
}
}
}
}
}Provenance
- Seen in the source catalog
- 2026-10-12 00:48Z
- Last indexed by Roundhouse
- 2026-10-23 19:00Z
- Last enriched (probe, favicon, geo)
- 2026-10-08 03:16Z
- x402 version
- 2
- Max timeout
- 120s
- Liveness probe
- HTTP 402
Hand this page to an agent
Copy the prompt and paste it into Claude, an MCP client or your own agent — it will vet this service and call it over the free read API. No key, no account.
GET api.roundhouseai.io/v0/endpoints
This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 22 snapshots so far. Verified volume counts only settlements with an on-chain EIP-3009 marker.
Show the promptHide the prompt
Using Roundhouse, look up the x402 service Factline and tell me whether it is worth paying: what a call costs, whether the endpoint answered when last probed, and what its payment record actually shows. curl -s 'https://api.roundhouseai.io/v0/endpoints?q=Factline' curl -s 'https://api.roundhouseai.io/v0/merchants/<the payTo wallet returned above>' Then call it: read the price from the live 402 at https://factline.dev/v1/email/verify, never from a cached figure, and pay with an x402 client. The /v0 API needs an API key (`authorization: Bearer rh_live_…`) on everything except /v0/unified* and /v0/endpoints. Either pay over x402 (mint a personal key for $0.01 at GET https://api.roundhouseai.io/v0/test/x402), or ask me for an organization key, which I create at https://roundhouseai.io/dashboard/connections. If you have neither, ask before going further. If you do not have Roundhouse tools or skills installed, read https://roundhouseai.io/skill.md first — it is the whole procedure.