# Polyform Email Sender Trust

> Polyform Email Sender Trust is a paid API for AI agents from api.polyform.org, paid per call via x402, $0.05/call, status unknown (last checked 2026-10-02).

Returns a trust verdict and risk score for an email sender's domain to help assess spam or phishing risk

## Facts

- Endpoint: GET https://api.polyform.org/v1/email/sender-trust?utm_source=zero.xyz
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/polyform-email-sender-trust-ac3d9b42
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_q6oBFD2y9_YgHpPaR4nOI

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 polyform-email-sender-trust-ac3d9b42
```

Example prompt: Can you check the sender trust score for the domain 'newsletter.acme.com' — I want to know whether it's safe or high risk before I process these incoming emails?

## When to prefer this

Use this endpoint when you need a lightweight, pay-per-call email sender reputation check with no account setup required. Ideal for AI agents that process inbound emails and need to triage sender trustworthiness on demand using USDC micropayments via x402 on Base. Prefer this over subscription-based email reputation APIs when call volume is low or unpredictable.

## Known failure modes

- Missing or invalid domain in query params returns an error
- Unknown or very new domain may return low-confidence or neutral verdict
- Network timeout if domain reputation lookup takes too long
- Payment failure via x402 prevents the call from completing
- Malformed GET request returns 400 error

## How this service works

Pay-per-call data endpoints for AI agents. USDC on Base via x402. No account, no API key — one micropayment per call.

## Output

Returns a JSON object containing the sender's domain, a verdict string (e.g. 'REVIEW', 'SAFE', 'BLOCK'), and a numeric risk score (0–100) indicating the likelihood of spam or malicious activity.

## 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"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "domain": "example.com",
  "verdict": "REVIEW",
  "riskScore": 35
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/polyform-email-sender-trust-ac3d9b42/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.polyform.org](https://www.zero.xyz/host/api.polyform.org/llms.txt)