Test Zoom Webhooks Locally (Receive Zoom Webhooks on localhost)

You are building a Zoom integration and you need to watch your handler react to a real event. The problem hits immediately: Zoom will only POST to a public URL, and your handler is running on localhost:8080. Zoom has no way to reach it.

The usual workarounds are slow. Deploying to a staging environment for every code change kills your iteration speed. Copying a sample payload out of the docs into curl gives you a guess at the real request, not the exact headers and body Zoom actually sends. What you really want is to test Zoom webhooks locally — real events, hitting your local handler, on a URL that does not change every time you restart.

This guide shows how to do exactly that.

Why testing Zoom webhooks locally is tricky

A webhook is just an HTTP request that Zoom sends to a URL when something changes. Zoom lives on the public internet; your dev machine usually does not. It sits behind a router, a corporate firewall, or both, with no public IP and no inbound ports open.

So you need something in the middle: a public endpoint Zoom can hit that relays each request down to your laptop without you opening a single firewall port. That is what Webhook Relay does — and unlike a random tunnel URL, the endpoint is stable, so you configure Zoom once and never touch it again.

Step 1: Inspect the real payload with Webhook Bin

Before you write any handler code, find out what Zoom actually sends. Open the free Webhook Bin — no signup — and you get an instant public URL.

1. Copy the Webhook Bin URL.
2. In the Zoom App Marketplace, open your app's Feature → Event Subscriptions, add a subscription, paste the URL, and select the events.
3. Trigger a real event and inspect the captured request.

You will see the full body and every header. The body is JSON with event, a payload object (the meeting/recording/user that changed) and an event_ts. Before any events arrive, Zoom sends a one-time endpoint.url_validation event you must answer.

Now you know the exact shape of the data before writing a line of code. For more on this approach, see How to test webhooks and What is a webhook.

Step 2: Forward the events to localhost with the relay agent

Once you know the payload, route those same events into your local handler. Sign up for Webhook Relay, install the relay agent (CLI or Docker), and create a bucket — say zoom. The bucket gives you a stable public input endpoint.

Start forwarding to your local server:

relay forward --bucket zoom http://localhost:8080/webhook

The agent opens an outbound connection to Webhook Relay and streams every incoming request down to http://localhost:8080/webhook. Because the connection is outbound, there are no firewall ports to open and no public IP needed — this works from your laptop, behind a corporate proxy, or inside a Kubernetes cluster. Running in Docker? The same command works in the official webhookrelay/webhookrelayd image. Full details are in the localhost forwarding docs.

Now point the Zoom webhook at your Webhook Relay endpoint (or create it there from the start), trigger an event, and watch it arrive on localhost.

Zoom-specific configuration and quirks

A few Zoom details worth knowing:

• Where to add it: the Zoom App Marketplace → your app → Feature → Event Subscriptions.
• URL validation: Zoom first sends an endpoint.url_validation event — respond with plainToken + encryptedToken or the subscription won't activate. Capturing it in a bin shows you the exact value to echo.
• Events: meetings, webinars, recordings, users and more — subscribe to what you need.
• Signature: v0= HMAC-SHA256 like Slack — see the verification step.

Step 3: Verify the Zoom webhook signature

Zoom signs every request. It builds the string "v0:{x-zm-request-timestamp}:{raw body}", computes an HMAC-SHA256 with your app's Secret Token, and sends it as v0=<hash> in the x-zm-signature header. Recompute it and compare in constant time. Note the one-time endpoint.url_validation handshake: when Zoom sends it, you must respond with a plainToken and its encryptedToken (HMAC-SHA256 of the plainToken with the Secret Token) to validate the endpoint.

To sanity-check an HMAC implementation, paste a captured body, your secret, and the received signature into the free HMAC signature verifier. For language-specific code and the common pitfalls (reading the body after a JSON parser has already consumed it, timing-safe comparison), read Verify a webhook signature.

Replay and iterate

This is where local development gets fast:

• Replay from Webhook Relay — past requests are stored on your bucket, so you can resend a captured event against your handler without touching Zoom at all.
• Iterate on your handler by editing code and replaying the same delivery until it behaves correctly. No commits, no pushes, no deploys just to test a single code path.
• Keep relay forward running while you work — events stream straight to localhost as you trigger them in Zoom.

Because the Webhook Relay endpoint is stable, you can stop and restart the agent, reboot your machine, or come back next week — the Zoom configuration never needs to change.

Get started

1. Inspect the real payload in the free Webhook Bin — no signup needed.
2. Create a Webhook Relay account, install the agent, and run relay forward --bucket zoom http://localhost:8080/webhook.
3. Point your Zoom webhook at the stable endpoint, trigger an event, and watch it hit localhost.

You will be testing real Zoom events against your local handler in a few minutes — no deploys, no open firewall ports, and a URL you configure exactly once.