The iszacka.dad API

Quick start

No keys, no sign-up, no SDK. If you can make an HTTP request, you can know whether Zack is a dad.

$ curl https://iszacka.dad/api/status.txt
no

curl iszacka.dad

curl -N https://iszacka.dad/api/stream

dig TXT answer.iszacka.dad +short

Status

The answer, in increasing levels of verbosity. These never cache (Cache-Control: no-store), because the answer could change at any moment.

{
  "isZackADad": false,
  "status": "no",
  "answer": "NO",
  "sentence": "Zack is not a dad. Yet.",
  "statusChangedAt": "2026-11-07T09:04:47.227Z",
  "dueDate": null,
  "daysUntilDue": null,
  "checks": 89,
  "links": {
    "self": "https://iszacka.dad/api/status",
    "html": "https://iszacka.dad/",
    "text": "https://iszacka.dad/api/status.txt",
    "history": "https://iszacka.dad/api/history",
    "updates": "https://iszacka.dad/api/updates",
    "dad": "https://iszacka.dad/api/dad",
    "stream": "https://iszacka.dad/api/stream",
    "rss": "https://iszacka.dad/feed.xml",
    "atom": "https://iszacka.dad/atom.xml",
    "jsonFeed": "https://iszacka.dad/feed.json",
    "calendar": "https://iszacka.dad/calendar.ics",
    "badge": "https://iszacka.dad/badge.svg",
    "embed": "https://iszacka.dad/embed",
    "docs": "https://iszacka.dad/api",
    "openapi": "https://iszacka.dad/openapi.json",
    "mcp": "https://iszacka.dad/mcp"
  }
}

Fields: status is no, soon (labour has started) or yes. daysUntilDue counts whole days in Europe/London and goes negative when overdue; it is null without a due date. checks is how many times anyone has asked.

History and updates

Every status change, the daily "still no" bulletin and the occasional announcement. Cached for 30 seconds.

{
  "updates": [],
  "nextBefore": null,
  "next": null
}

GET /api/dad

Request one dad. Until the baby arrives this returns 425 Too Early (RFC 8470), with a Retry-After computed from the due date; afterwards it returns 201 Created with Location: /. POST works too.

HTTP/1.1 425 Too Early
Content-Type: application/json

{
  "error": "too_early",
  "status": "no",
  "isZackADad": false,
  "message": "Too early. The dad you requested has not been delivered yet.",
  "dueDate": null,
  "retryAfterSeconds": null,
  "retryAt": null
}

Retry-After counts down to midnight (London time) on the due date, drops to an hour once overdue, and to a minute during labour. Without a due date there is no Retry-After, only hope.

Feeds

The latest 50 updates in every syndication format worth having. Cached for 60 seconds, with ETags, so a polite reader gets a 304.

webcal://iszacka.dad/calendar.ics

curl -sI https://iszacka.dad/feed.xml | grep -i etag
curl -s -o /dev/null -w '%{http_code}\n' -H 'If-None-Match: "<etag>"' https://iszacka.dad/feed.xml   # 304

Badges and embeds

Put the answer on your README, your wiki, your intranet or your fridge (see /poster for the fridge).

[![Is Zack a dad?](https://iszacka.dad/badge.svg)](https://iszacka.dad/)

<iframe src="https://iszacka.dad/embed" title="Is Zack a dad?" width="320" height="180" style="border:0"></iframe>

<script src="https://iszacka.dad/embed.js" data-theme="auto" data-size="medium" async></script>

MCP server

For AI assistants that want to ask nicely. A stateless Model Context Protocol server over Streamable HTTP at /mcp, answering with plain JSON.

Protocol versions: 2026-07-28, 2025-11-25, 2025-06-18, 2025-03-26. Version 2026-07-28 clients send per-request _meta and the MCP-Protocol-Version, Mcp-Method and Mcp-Name headers (all validated); older clients initialize first. GET /mcp returns 405: there is no stream to listen to.

{
  "mcpServers": {
    "is-zack-a-dad": {
      "type": "http",
      "url": "https://iszacka.dad/mcp"
    }
  }
}

claude mcp add --transport http is-zack-a-dad https://iszacka.dad/mcp

curl -s https://iszacka.dad/mcp \
  -H 'Content-Type: application/json' \
  -H 'Accept: application/json, text/event-stream' \
  -H 'MCP-Protocol-Version: 2026-07-28' \
  -H 'Mcp-Method: tools/call' \
  -H 'Mcp-Name: is_zack_a_dad' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"is_zack_a_dad","arguments":{},"_meta":{"io.modelcontextprotocol/protocolVersion":"2026-07-28","io.modelcontextprotocol/clientCapabilities":{}}}}'

curl -s https://iszacka.dad/mcp \
  -H 'Content-Type: application/json' \
  -H 'Accept: application/json, text/event-stream' \
  -d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-06-18","capabilities":{},"clientInfo":{"name":"curl","version":"1.0"}}}'

Machine-readable odds and ends

For crawlers, auditors, language models and the terminally curious.

Elsewhere on the site

Endpoints run by other parts of the operation, listed here so this page can honestly claim to cover everything.

Etiquette

The small print, kept small.

• CORS: every /api endpoint and /mcp sends Access-Control-Allow-Origin: * and answers preflight OPTIONS requests. Feeds and the badge do too.
• Rate limits: 120 requests a minute per IP across the API. Go over and you get 429, a JSON body and a Retry-After. Polling once a minute is plenty; the baby will not arrive faster if you refresh harder.
• Caching: status endpoints are no-store; history and updates cache for 30 seconds; feeds and the badge for 60 seconds with ETags.
• Polling: add ?poll=1 to /api/status when a timer, not a person, is asking. You get the same answer, and the public "times checked" counter isn't inflated by your dashboard.
• Headers: every response carries X-Is-Zack-A-Dad and, when there's a due date, X-Days-Until-Due. Server-Timing includes the estimated gestation so far, in milliseconds, because it can.
• Privacy: the site knows the status, when it changed and the due date. That is all it will ever know, so please don't ask the API for names or weights.