# Email Syntax Check Watch (Change Detection)

> Email Syntax Check Watch (Change Detection) is a paid API for AI agents from intel.rallylive.ca, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-14).

Checks email address syntax validity and detects changes compared to the previous check for the same email, returning current result, a changed flag, field-level diffs with before/after values, and last-seen timestamp.

## Facts

- Endpoint: GET https://intel.rallylive.ca/watch/email/syntax
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/email-syntax-check-watch-change-detection-266f2f5f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_P2wgRscLaqbEqmmWBnoB1

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 email-syntax-check-watch-change-detection-266f2f5f
```

Example prompt: Keep an eye on the syntax check for user@example.com and let me know if the result changes from the last time you checked — show me exactly which fields are different and what they were before.

## When to prefer this

Choose this endpoint when you need change detection on email syntax checks, not just a one-off validation. It is ideal for scheduled/polling workflows where you want to be notified only when the validity result actually changes, with a structured diff of what changed. Prefer this over a simple syntax check when you need historical comparison, audit trails, or event-driven automation triggered by validation state changes.

## Known failure modes

- No email query parameter provided — returns error indicating required input missing
- Email not previously checked — no stored baseline, so 'changed' will be false or unavailable for first call
- Stored result expired (older than 90 days) — comparison baseline lost, treated as first-time check
- Invalid HTTP method — only GET is supported
- Payment failure — x402 payment not provided or insufficient, request rejected

## How this service works

Change watch for email syntax check: runs the check and compares it with the result from your previous call for the same email (kept 90 days), returning the current answer, changed true/false, exactly which fields changed with before/after values, and when it was last seen. Call it on a schedule to be told when fast email syntax check changes. $0.01 per check.

## Output

Returns the current email syntax check result (valid/invalid), a boolean 'changed' flag indicating whether the result differs from the previous call for that email (stored up to 90 days), a list of exactly which fields changed with before and after values, and the timestamp of when the email was last seen/checked.

## 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"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/email-syntax-check-watch-change-detection-266f2f5f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from intel.rallylive.ca](https://www.zero.xyz/host/intel.rallylive.ca/llms.txt)