Zapier+DiffHook

Zapier webhook trigger — the minute a page changes

DiffHook watches any URL, RSS feed, or JSON API and fires a Zapier Catch Hook the moment the content moves. No Schedule by Zapier, no Code step, no premium-only integrations — just a webhook.

The usual "run a Zap when this website changes" build is Schedule by Zapier + Webhooks by Zapier GET + a Code step to compare responses. It works, but it eats a Zap task on every poll (whether anything changed or not), and the diff logic lives in your head. DiffHook does the polling and the diff on its side and fires a single task into Zapier per real change. Tasks line up with events; your Zap plan goes a lot further.

Start freeRead the webhook docs

Workflow

Wire DiffHook into a Zap in 5 steps

Standard Webhooks by Zapier — no premium tier, no Code step, no Schedule trigger.

01

Create a Zap that starts with a Catch Hook

In Zapier, pick Webhooks by Zapier → Catch Hook as your trigger. Zapier gives you a unique URL — copy it, you'll paste it into the DiffHook monitor in step 3.

02

Decide what DiffHook should watch

Pick the source: a URL with a CSS selector for websites, a JSON path for APIs, or a feed URL for RSS. DiffHook handles fetch, cache, and diff — Zapier never polls anything.

03

Point a DiffHook monitor at the Catch Hook

POST to /v1/monitors with the source config, an interval, and a webhook-type delivery whose URL is the Zapier Catch Hook. DiffHook starts checking within seconds; Zapier starts listening.

04

Verify HMAC inside Zapier

Add a Filter step (or a Paths fork) that checks the X-DiffHook-Signature header using the static signing secret DiffHook gives you. Zapier exposes header values as named fields — no Code step needed.

05

Branch on the change payload

Use the fields Zapier pulls out of the JSON body — previous_value, current_value, url, detected_at — to drive downstream actions: Slack message, Airtable row, Gmail draft, or whatever your Zap does.

API example

A Zapier-backed monitor, one POST

The Zap Catch Hook URL goes in deliveries[0].url. DiffHook takes over from there — no Schedule, no Code, no polling.

POST /v1/monitors
POST https://api.diffhook.com/v1/monitors
Authorization: Bearer $DIFFHOOK_API_KEY
Content-Type: application/json

{
  "type": "html_css",
  "url": "https://competitor.example.com/features",
  "css_selector": ".pricing-table",
  "interval_seconds": 600,
  "deliveries": [
    {
      "type": "webhook",
      "url": "https://hooks.zapier.com/hooks/catch/000000/abc123/"
    }
  ]
}

Importable workflow

Copy a ready-made Zap

A template Zap with the Catch Hook, a signature-check Filter, and a Slack step. Import the blueprint from GitHub, paste your DiffHook webhook URL and secret, and publish.

View the Zap template on GitHub

FAQ

Zapier webhook — common questions

Why not just use Zapier's Schedule + Webhooks GET to poll a URL?
Because it burns a Zap task on every poll, changed or not. A 15-minute poll across a year is ~35,000 tasks just to catch a handful of actual changes. DiffHook does the polling outside Zapier and fires one task per real change — on a Starter plan, that's the difference between surviving the week and hitting the overage wall.
Do I need the Webhooks by Zapier premium app?
Catch Hook is part of the free Webhooks by Zapier trigger — available on every Zapier plan. You do not need the premium-only Zapier Code step for this setup, because HMAC verification can be done with a Filter step that compares the X-DiffHook-Signature header against a fixed value.
Can a single Zap handle multiple monitors?
Yes. Point several DiffHook monitors at the same Catch Hook URL, then branch in the Zap on monitor_id or on url. Useful when you want one notification destination (e.g. a marketing Slack channel) fed by several different DiffHook monitors.
What does the JSON body look like?
Flat, Zapier-friendly. monitor_id, event, url, selector (or json_path for API monitors), previous_value, current_value, detected_at, delivery_id. Zapier's auto-parse picks up every top-level field so you can map them into downstream actions without a Code step.
Can I retry or replay a failed delivery?
Yes. DiffHook retries 5xx responses automatically (exponential backoff, 24-hour horizon). For 4xx responses — or if your Zap was paused — open the monitor in the dashboard, find the delivery, and replay it with one click. Zapier receives it as a fresh event.

Related workflows

Also great with DiffHook

Zapier web scraping

Same pattern for HTML scraping — Zapier receives the scraped diff, no Code step needed.

n8n webhook

Prefer self-hosted automation? Point the same DiffHook monitor at an n8n webhook instead.

Pipedream webhook

For longer Node/Python steps and longer retention, Pipedream works with the same DiffHook payload.

API endpoint monitoring

Watching a JSON API instead of HTML? Same Zap, JSONPath in place of a CSS selector.

RSS to webhook

Feed-to-webhook if your source is RSS rather than HTML — same Zapier Catch Hook destination.

Make.com web scraping

Migrating from Zapier? Make.com's webhook module accepts the identical DiffHook payload.

Stop burning Zap tasks on empty polls

One task per real change, HMAC-signed payloads, Catch Hook trigger, free tier. Set up in under five minutes.

Create free accountSee pricing