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MailPulse Physical Letter Send
x402
MailPulse Physical Letter Send is a paid API for AI agents from mailpulse.theaslangroupllc.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-13).
Sends a real physical letter via USPS (First-Class, Certified Mail, or international) using x402 micropayments, powered by Lob
Price / call$0.005
Success—
StatusUnknown
How this service works
MailPulse sends REAL physical letters — US First-Class, US Certified Mail, or international — via x402 micropayments. Action, not data: free quote, paid send, optional tracking. Powered by Lob.
Output
Returns a JSON object with the letter ID (ltr_...), mode (test/live), current status (e.g. rendered, mailed), carrier (USPS), optional tracking number if Certified Mail was selected, and expected delivery date.
Example use cases
Legal notice via certified mail
“Send a certified mail letter to Robert Johnson at 789 Elm Street, Chicago IL 60601 from my law firm at 100 LaSalle St, Chicago IL 60602 — the content is a formal notice of contract termination. I need tracking so I can confirm delivery.”
Automated customer invoice mailing
“Mail a physical invoice letter to our client TechCorp at 500 Market St, San Francisco CA 94105 — it's from Billing Dept at 200 Pine St, Portland OR 97201, and the letter text is 'Dear TechCorp, please find your invoice #1042 for $2,500 attached. Payment due in 30 days.' Use US First-Class mail.”
International letter to overseas contact
“Send a physical letter internationally to Maria Garcia at Calle Mayor 10, Madrid 28013, Spain — from us at 300 Fifth Ave, New York NY 10001. The message is 'Dear Maria, we are pleased to confirm your partnership agreement. We look forward to working together.'”
Technical details
Endpoint
POSThttps://mailpulse.theaslangroupllc.com/api/letters/%7Bid%7DWhen to prefer
Choose this endpoint when you need to physically mail a real letter via USPS — including First-Class, Certified Mail with tracking, or international delivery — and want to pay per-send via x402 micropayments without a monthly subscription. Prefer this over email or SMS APIs when a legal paper trail, certified delivery proof, or formal physical document is required. Ideal for agents automating invoice mailing, legal notices, or customer communications that must arrive as tangible paper.
Side effects
- Invalid or undeliverable address returns an address validation error
- Missing required fields (recipient, sender, content) result in a 400 bad request
- Insufficient USDC balance or failed x402 payment results in a 402 payment required error
- International addresses not supported for certain mail classes return a service restriction error
- Letter ID path parameter malformed or missing causes a 404 or routing error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"id": "ltr_...",
"mode": "test",
"status": "rendered",
"carrier": "USPS",
"tracking_number": null,
"expected_delivery_date": "2026-07-23"
}
}Tags
x402
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