# Machine Inbox Pro — Pay-per-use Email Inbox for Agents

> Machine Inbox Pro — Pay-per-use Email Inbox for Agents is a paid API for AI agents from machineinbox.com, paid per call via x402, $5/call, status unknown (last checked 2026-10-11).

Creates a persistent, pay-per-use professional email inbox (7-day lifespan) for software agents, funded via x402 USDC or Stripe, with HTTP-based mail receive and reply.

## Facts

- Endpoint: POST https://machineinbox.com/api/v1/inboxes/pro?utm_source=zero.xyz
- Price: $5/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/machine-inbox-pro-pay-per-use-email-inbox-for-agents-f9430710
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_EAfvz2EYrRpj6zJyj2v0o

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 machine-inbox-pro-pay-per-use-email-inbox-for-agents-f9430710 -d '<json body>'
```

Example prompt: Create a new pro email inbox for my agent — one that lasts seven days and supports both receiving mail and replying over HTTP, and pay for it with USDC.

## When to prefer this

Choose this endpoint when your agent needs a real, replyable email inbox that persists for seven days and must support full two-way communication over HTTP — as opposed to the one-hour verification inbox (for single-use signup codes) or the basic inbox (shorter lived or fewer features). Ideal for multi-step agent workflows that involve email-based back-and-forth with humans or services over several days.

## Known failure modes

- Payment failure: insufficient USDC balance or invalid x402/Stripe payment header returns 402 Payment Required
- Malformed request body: missing required fields (type, method, bodyType, body) returns 400 Bad Request
- Rate limiting or quota exceeded returns 429 Too Many Requests
- Service unavailability returns 503 with no inbox created
- Expired or invalid bearer token on subsequent calls returns 401 Unauthorized

## How this service works

Pay-per-use email inboxes for software agents. Pay $2.00 through Stripe Machine Payments Protocol or x402 USDC, receive mail, and reply over HTTP.

## Output

Returns a JSON object containing the new inbox's UUID, its full email address (e.g. m_example@in.machineinbox.com), an expiration timestamp seven days out, and a bearer token (mi_live_...) used to authenticate subsequent HTTP calls to read mail and send replies.

## 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",
     "additionalProperties": false
    },
    "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"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "inbox": {
   "id": "uuid",
   "address": "m_example@in.machineinbox.com",
   "expiresAt": "2026-09-17T12:00:00.000Z"
  },
  "token": "mi_live_..."
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/machine-inbox-pro-pay-per-use-email-inbox-for-agents-f9430710/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from machineinbox.com](https://www.zero.xyz/host/machineinbox.com/llms.txt)