€9,99 per month is a paywall, €1,450 per month is the rent, and two digits is the whole difference

Description and use

Notifio auto‑fills contact forms on rental sites but must refuse when a page is a payment or subscription form. Deterministic checks for payment SDK scripts, card fields, and two‑digit subscription price patterns prevent submissions to payment pages.

Problem

Detecting payment or subscription pages on rental listings to avoid sending contact forms to payment flows.

Outcome

The guard logic prevents the app from submitting contact forms on payment or subscription pages, reducing wasted attempts and avoiding accidental subscriptions.

Workflow

• 1. Load page HTML and status code.
• 2. Check for HTTP 402 status and block if present.
• 3. Search for payment SDK script hosts (e.g., js.stripe.com, mollie.nl).
• 4. Search for card field attributes (autocomplete="cc-number", name="cardnumber", id="card-element").
• 5. If any markers found, block with detail "Payment form detected on page".
• 6. Search for two‑digit subscription price patterns (e.g., "€9,99 per month").
• 7. If matched, block with detail "Subscription required".
• 8. Otherwise, allow form submission.

Evidence

Notifio watches rental search pages and, if you have bought the upgrade for it, fills in the contact form on a new listing for you.

Source

The first group is payment service provider script hosts. A page that has loaded js.stripe.com is a page that intends to take a card, regardless of what its copy says.

Source

The price of a subscription to the site itself: "€9,99 per month", "9.99 p/m", "€ 15 per maand", "15 € pro Monat". Capped at two digits on purpose.

Source