# InboxPolicy Send-Decision Email Verification API

> InboxPolicy Send-Decision Email Verification API is a paid API for AI agents from api.inboxpolicy.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-12).

Verifies an email address and returns an actionable send-decision (send, review, or avoid) with confidence score and deliverability signals

## Facts

- Endpoint: POST https://api.inboxpolicy.com/v1/verify?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/inboxpolicy-send-decision-email-verification-api-d09f0e38
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_PeHIFMqCu61iw71sYj1Rk

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 inboxpolicy-send-decision-email-verification-api-d09f0e38 -d '<json body>'
```

Example prompt: Can you check whether john.doe@example.com is safe to email — I need a send-or-avoid decision with confidence score and any signals like whether it's disposable or a catch-all?

## When to prefer this

Use this endpoint when you need an opinionated, evidence-backed send-or-avoid decision rather than just a syntax check or basic MX lookup. Prefer it for pre-send validation in email outreach pipelines, list hygiene workflows, and transactional email systems where bounce rates and reputation matter. The $0.01/call pay-per-use model with no account required makes it ideal for sporadic or agent-driven verification without subscription overhead. The built-in 72h verification cache reduces cost for repeated checks on the same address.

## Known failure modes

- Invalid or malformed email syntax returns status: syntax_error and action: avoid
- Greylisted or temporarily unresponsive mail servers return status: temporary_unavailable and action: retry_later
- Catch-all domains return low-confidence results since individual address existence cannot be confirmed
- Cached results (within 72h window) are returned by default; use force_refresh: true to bypass
- Payment failure via x402 will prevent the request from completing
- Rate limits or network errors may return HTTP 429 or 5xx responses

## How this service works

Email verification API that returns a decision — send, review, or avoid — with evidence. $0.01/call via x402, no account. Free 72h re-verification.

## Output

Returns a JSON object with an action enum (send, send_with_caution, review, retry_later, or avoid), a confidence integer (0–100), a deliverability status (valid, invalid, unknown, temporary_unavailable, syntax_error), a human-readable reason string, and a signals object with boolean flags for disposable, catch_all, role_account, and free provider. Also includes a from_cache flag, a request_id for tracing, and billing metadata.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "email"
 ],
 "properties": {
  "email": {
   "type": "string",
   "description": "Address to evaluate."
  },
  "strictness": {
   "enum": [
    "aggressive",
    "default",
    "strict"
   ],
   "type": "string"
  },
  "force_refresh": {
   "type": "boolean",
   "description": "Bypass the 72h verification cache."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "action",
  "confidence",
  "status"
 ],
 "properties": {
  "cost": {
   "type": "object",
   "properties": {
    "credits": {
     "type": "integer"
    },
    "billable": {
     "type": "boolean"
    }
   }
  },
  "action": {
   "enum": [
    "send",
    "send_with_caution",
    "review",
    "retry_later",
    "avoid"
   ],
   "type": "string"
  },
  "reason": {
   "type": "string"
  },
  "status": {
   "enum": [
    "valid",
    "invalid",
    "unknown",
    "temporary_unavailable",
    "syntax_error"
   ],
   "type": "string"
  },
  "signals": {
   "type": "object",
   "properties": {
    "free": {
     "type": "boolean"
    },
    "catch_all": {
     "type": "boolean"
    },
    "disposable": {
     "type": "boolean"
    },
    "role_account": {
     "type": "boolean"
    }
   }
  },
  "confidence": {
   "type": "integer",
   "maximum": 100,
   "minimum": 0
  },
  "from_cache": {
   "type": "boolean"
  },
  "request_id": {
   "type": "string",
   "example": "vrf_..."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/inboxpolicy-send-decision-email-verification-api-d09f0e38/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.inboxpolicy.com](https://www.zero.xyz/host/api.inboxpolicy.com/llms.txt)