# Synapse Email Verification API

> Synapse Email Verification API is a paid API for AI agents from anibalb.duckdns.org, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-31).

Verifies whether an email address actually exists by performing an SMTP check, returning existence status and server response

## Facts

- Endpoint: GET https://anibalb.duckdns.org/x402/verify-email?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/synapse-email-verification-api-2bfa7ed2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_0-J66cW91tdVyHd3hu08o

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 synapse-email-verification-api-2bfa7ed2
```

Example prompt: Can you check whether the email address john.doe@example.com actually exists and has a live inbox?

## When to prefer this

Use this endpoint when you need real-time SMTP-level email verification — going beyond simple format checks to actually probe the mail server. Ideal for lead validation, signup fraud prevention, or CRM hygiene. Preferred over format-only validators when deliverability confirmation matters. The pay-per-call x402 model means no subscription or API key setup required.

## Known failure modes

- Invalid or malformed email address format returns error
- Greylisting or SMTP anti-spam measures may cause false negatives
- Some mail servers accept all addresses regardless of validity (catch-all), producing false positives
- Network timeouts if the target mail server is unreachable
- Rate-limiting or blocking by aggressive mail servers

## How this service works

Public data and utility APIs paid per call in USDC on Base (x402). No accounts, no API keys. 174 routes: crypto/equity data, onchain reads, DNS/email/security intel, geo/weather, x402 payment diagnostics, dev utilities and more.

## Output

A JSON object containing a boolean 'exists' field indicating whether the email address has a live inbox, and an 'smtp_response' string with the raw SMTP server response code and message (e.g. '250 2.1.5 OK').

## 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",
      "HEAD",
      "DELETE"
     ],
     "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": {
  "exists": true,
  "smtp_response": "250 2.1.5 OK"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/synapse-email-verification-api-2bfa7ed2/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from anibalb.duckdns.org](https://www.zero.xyz/host/anibalb.duckdns.org/llms.txt)