Recipe · Watchers & scrapers

Point a script at anything. Get tapped when it changes.

Restock watches, price drop alerts, appointment slots — the pattern is always the same loop: fetch, check, and when the thing finally happens, one POST /v1/notify buzzes your WhatsApp. Text join to get a key, paste the loop, walk away.

§ 1

The watcher loop

The whole recipe is a dozen lines. Poll the page on a polite interval, and the moment your condition flips, send yourself a ping. Swap the if line for whatever you're watching — a price under a threshold, a "sold out" badge disappearing, a calendar slot opening up.

restock_watch.py

import httpx, os, time

while True:
    page = httpx.get("https://shop.example/product/42").text
    if "out of stock" not in page.lower():
        httpx.post("https://pingwa.dev/v1/notify",
                   headers={"Authorization": f"Bearer {os.environ['PINGWA_KEY']}"},
                   json={"text": "Restock: product 42 is back 📦"})
        break
    time.sleep(300)

Run it under nohup, tmux, cron, a Raspberry Pi — anywhere Python runs. The break means it pings once and stops; drop it if you want a standing watcher (see the FAQ on duplicate pings).

§ 2

Two-way: ask before acting

If the watcher should do something — add to cart, book the slot — don't let it act alone. Swap /v1/notify for POST /v1/ask: it sends the question with tap buttons and holds the connection open until you answer (up to 90 s, so give httpx a slightly longer timeout). Buttons get positional ids — b0 is the first button, b1 the second, b2 the third. If the watcher fires outside your 24h reply window (likely, when it triggers days later), the buttons arrive as a numbered list instead of tap buttons — replying 1 works the same and still maps to b0.

restock_watch_and_ask.py

import httpx, os, time

while True:
    page = httpx.get("https://shop.example/product/42").text
    if "out of stock" not in page.lower():
        r = httpx.post("https://pingwa.dev/v1/ask",
                       headers={"Authorization": f"Bearer {os.environ['PINGWA_KEY']}"},
                       json={"text": "Restock found — buy now?",
                             "buttons": ["yes", "no"],
                             "timeout": 90},
                       timeout=95)
        if r.status_code == 200 and r.json()["reply"]["button_id"] == "b0":
            buy_product_42()   # your checkout logic
        break
    time.sleep(300)

A 408 means you didn't answer within the window — the question is still delivered, and the reply stays retrievable via GET /v1/messages/<id>/reply. See the API docs for the full response shapes.

§ 3

Or just tell your agent to build it

Don't feel like writing the loop? Hand the job to your coding agent — the docs are agent-readable.

✂ paste this to your coding agent

Build me a Python watcher that checks <URL> every 5 minutes and asks me on WhatsApp before buying. API docs: https://pingwa.dev/llms.txt

§ 4

FAQ

Can I get a price drop alert on WhatsApp?

Yes — that's the same loop with a different condition. Parse the price out of the page (a regex or BeautifulSoup one-liner), compare it to your threshold, and POST /v1/notify with the price in the text when it drops. Track the last-seen price in a file if you want "dropped since yesterday" rather than "below X".

How do I write a restock notification script?

Recipe § 1 above is exactly that. Two honest caveats: keep the interval polite — every 5 minutes (time.sleep(300)) is plenty for a restock, and hammering a shop every few seconds is a good way to get your IP blocked. And if a site sits behind serious bot protection, pingwa can't help with that part — it delivers the ping, it doesn't bypass anyone's defenses. Check the site's terms before you scrape it.

Can I build an appointment slot checker that pings my phone?

Same skeleton: fetch the booking page (or its JSON endpoint — check the network tab, it's usually cleaner than HTML), test whether a slot appears, and notify. Slots vanish fast, so this is the case for the § 2 variant: /v1/ask with buttons, so you can approve the booking from your phone the moment the watcher finds one.

My watcher is flaky and pings me twice for the same event.

Send an Idempotency-Key header with a value derived from the event (e.g. restock-product-42-2026-07-16). pingwa honors the key for 24 hours: the same key replays the original result — no duplicate message, no extra quota — even if your loop fires twice or a retry races. Same key with a different body returns 409.

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Watchers poll on your machine, on your responsibility — respect each site's terms and rate limits. pingwa only carries the ping, over the official Meta Cloud API. The free plan's 30 paid messages a month go a long way here: a watcher that fires once when the thing happens costs one.