# 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 2026-09-15).

Retrieves the render status, expected delivery date, and USPS tracking number (for certified mail) of a previously sent physical letter.

## Facts

- Endpoint: POST https://mailpulse.theaslangroupllc.com/api/letters/ltr_1a9b185b1c4ee035
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/mailpulse-letter-status-tracking-318be170
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_veovSQh5WVYJC2CfJwgTG

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-318be170 -d '<json body>'
```

Example prompt: Can you check the status of the physical letter I sent last week — the letter ID is ltr_1a9b185b1c4ee035 — and let me know if it's been rendered, when it's expected to arrive, and the USPS tracking number if it was sent certified?

## When to prefer this

Use this endpoint when you have already sent a letter via the MailPulse POST /api/letters endpoint and need to check its current processing status, confirm it has been handed off to USPS, retrieve the expected delivery date, or obtain a USPS tracking number for certified mail. This is specifically for post-send status lookups, not for creating new letters.

## Known failure modes

- Letter ID not found — returns error if ltr_... ID doesn't exist or belongs to a different account
- Letter not yet processed — status may be pending if called immediately after submission
- Invalid letter ID format — returns error for malformed IDs
- Payment failure — endpoint requires $0.005 USDC per call via x402 protocol; missing payment returns 402
- Network timeout — occasional latency spikes when querying upstream USPS tracking data

## 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. processing, rendered, mailed), the expected delivery date, and — for certified mail — the USPS tracking number that can be used to monitor delivery on the USPS website.

## 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-318be170/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)