Webhook

A webhook is a mechanism for one application to notify another application, in real time, that something happened — by sending an HTTP POST request containing a data payload to a pre-configured URL, the moment the event occurs. Webhooks are the backbone of nearly every no-code integration: when you connect Stripe to Zapier, or Typeform to Make, the "instant" trigger you select in the builder is a webhook under the hood. Why it matters: webhooks are the efficient alternative to polling (repeatedly asking "did anything change yet?"). Instead of an automation platform checking a source system every few minutes and burning API rate limits, the source system pushes data the instant something happens — faster, cheaper, and more reliable at scale. For AI/SaaS builders, understanding webhooks is essential because most third-party integrations (payment processors, CRMs, form builders, chat platforms) expose webhooks as their primary real-time integration point, and debugging "why didn't my Zap fire" almost always comes down to a webhook configuration, signature-verification, or payload-shape issue. How it works: (1) the receiving app exposes an endpoint URL (e.g., `https://hooks.zapier.com/hooks/catch/123456/abcdef/`); (2) the sending app is configured with that URL as a "webhook subscription" for a specific event type (e.g., `payment.succeeded`); (3) when the event fires, the sending app makes an HTTP POST to that URL with a JSON body describing the event; (4) the receiving app parses the payload and triggers its own logic. Worked example — a Stripe webhook payload sent when a customer completes a checkout: `POST /webhook HTTP/1.1` with a JSON body like `{"id": "evt_1N3T2x", "type": "checkout.session.completed", "data": {"object": {"customer_email": "jane@example.com", "amount_total": 4900, "currency": "usd"}}}`. A no-code automation platform receiving this can extract `customer_email` and `amount_total`, then trigger an action like "add Jane to the Paid Customers list in ConvertKit." Production-grade webhook handling requires two things builders often skip: signature verification (checking a header like `Stripe-Signature` against a shared secret to confirm the payload really came from Stripe and wasn't spoofed) and idempotency (handling the same webhook delivered twice, which happens during retries, without double-processing — e.g., creating two duplicate orders). Most no-code platforms provide a generic "Catch Webhook" trigger specifically so builders can receive events from apps that don't have a dedicated pre-built connector — pasting the platform's auto-generated URL into any third-party system's "webhook URL" setting is often the fastest way to wire up an integration the vendor has never officially built.