# MailPulse Letter Status & Tracking

> MailPulse Letter Status & Tracking is a paid API for AI agents from mailpulse.theaslangroupllc.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-11).

Check the render status, expected delivery date, and USPS tracking number of a previously sent physical letter by its letter ID.

## Facts

- Endpoint: POST https://mailpulse.theaslangroupllc.com/api/letters/ltr_6efe036558965c36?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/mailpulse-letter-status-tracking-198f12de
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_PO6fDzGta017DbpGnM82y

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability mailpulse-letter-status-tracking-198f12de -d '<json body>'
```

Example prompt: What's the status of the physical letter I sent yesterday — the ID was ltr_6efe036558965c36? I want to know if it's been rendered, when it's expected to arrive, and if it was certified mail, give me the USPS tracking number.

## When to prefer this

Use this endpoint after sending a physical letter via MailPulse's POST /api/letters endpoint when you need to confirm the letter was successfully rendered, retrieve the expected delivery date for scheduling or follow-up, or obtain the USPS tracking number for certified mail. Prefer this over generic USPS tracking lookups when the letter was sent through MailPulse, as it provides render status in addition to delivery tracking.

## Known failure modes

- Letter ID not found — returns 404 if the ltr_* ID does not exist or belongs to a different account
- Letter still processing — render status may be pending if recently submitted
- Invalid letter ID format — malformed ltr_* ID returns a validation error
- Authentication failure — missing or invalid x402 payment header returns 402

## How this service works

Check the status and tracking of a physical letter previously sent via POST /api/letters. Returns render status, expected delivery date, and (for certified mail) the USPS tracking number.

## Output

Returns the letter's current render status (e.g. rendered, failed), the expected delivery date, and for certified mail letters, the USPS tracking number. May also include additional letter metadata such as mail type and timestamps.

## Request schema (JSON Schema)

```json
{
 "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",
     "properties": {}
    },
    "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"
    },
    "errors": {
     "type": "object",
     "description": "Documented error responses, keyed by HTTP status code",
     "additionalProperties": {
      "type": "object",
      "required": [
       "description"
      ],
      "properties": {
       "example": {
        "type": "object"
       },
       "description": {
        "type": "string"
       }
      }
     }
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/mailpulse-letter-status-tracking-198f12de/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from mailpulse.theaslangroupllc.com](https://www.zero.xyz/host/mailpulse.theaslangroupllc.com/llms.txt)