Configuring webhooks as a destination in Event Notifications

A webhook represents a service destination, where an incoming notification can be consumed programmatically. For example, an incoming notification about an event can trigger a webhook destination to a backend microservice to act based on the content of the incoming notification.

Configuring a webhook destination

You can configure a webhook destination on the Destinations tab. As part of the configuration, enter the webhook URL, and the REST API verb to be called when the webhook is called. You can also enter authorization headers to the destination webhook. Create a subscription to associate the webhook destination to a topic.

Supported HTTP verbs

Event Notifications webhooks support the HTTP verbs GET, POST, PUT, and PATCH.

  • GET : Retrieves a representation of the specified resource.
  • POST : Creates a new resource.
  • PUT : Replaces the entire resource with the provided data.
  • PATCH : Applies partial modifications to a resource.

Webhook signing

To identify that the incoming notification is coming from IBM Cloud Event Notifications, you can enable webhook signing. If signing is enabled, a public key can be downloaded, and used to decrypt the incoming notification content.

Allowlisting IP addresses

You can allowlist the IP address ranges to restrict access to the servers that receive webhooks. Ensure that the following IP addresses are all allowlisted:

Existing webhook IP addresses

These webhook IP addresses are deprecated at the end of September 2026. After that date, webhooks are no longer delivered from these IP addresses. Ensure that you allowlist the new IP addresses.

New IP addresses

Effective starting August 29, 2026:

  • Global common IP addresses: See Individual IP addresses for multi-zone regions.

  • Region-specific IP addresses: Allowlist the IP addresses for the region where your Event Notifications service instance is deployed. If you use Event Notifications service instances in multiple regions, allowlist the IP addresses for each applicable region.

Dallas (us-south)

  • Public

    52.118.150.206
52.118.211.163
67.18.95.240

  • Private

    10.22.12.198
10.22.26.163
10.119.56.147

Sydney (au-syd)

  • Public

    159.23.97.10
130.198.9.234
135.90.131.19

  • Private

    10.223.237.137
10.51.176.13
10.223.253.235

London (eu-gb)

  • Public

    158.176.171.145
158.175.189.21
141.125.162.123

  • Private

    10.16.48.81
10.16.62.205
10.223.21.154

Madrid (eu-es)

  • Public

    13.121.86.163
13.122.88.117
13.120.93.85

  • Private

    10.22.177.232
10.22.195.222
10.22.202.91

Frankfurt (eu-de)

  • Public

    149.81.4.209
149.81.212.50
158.176.1.49

  • Private

    10.16.206.123
10.22.112.128
10.16.216.36

Osaka (jp-osa)

  • Public

    163.68.88.77
163.69.84.115
163.73.93.115

  • Private

    10.12.21.131
10.12.33.173
10.12.38.219

Tokyo (jp-tok)

  • Public

    165.192.134.77
162.133.141.117
128.168.131.96

  • Private

    10.223.197.48
10.223.201.138
10.223.213.141

Toronto (ca-tor)

  • Public

    163.74.90.220
163.75.87.40
163.66.93.241

  • Private

    10.223.149.61
10.223.166.200
10.223.182.99

Montreal (ca-mon)

  • Public

    64.5.42.20
64.5.48.239
64.5.44.233

  • Private

    10.46.73.140
10.46.77.140
10.46.81.140

Sao Paulo (br-sao)

  • Public

    13.116.82.0
163.107.92.208
163.109.92.155

  • Private

    10.12.183.145
10.12.71.56
10.51.193.111

Washington DC (us-east)

  • Public

    52.117.124.52
169.63.177.17
150.239.80.160

  • Private

    10.22.41.152
10.22.50.51
10.12.118.230

Chennai (in-che)

  • Public

    169.38.17.66
169.38.9.38
169.38.13.18

  • Private

    10.46.128.179
10.46.132.179
10.46.136.179

Mumbai (in-mum)

  • Public

    169.38.211.191
169.38.236.49
169.38.42.162

  • Private

    10.223.94.240
10.223.103.208
10.249.119.171

Webhook retry policy

When calling a webhook, issues such as network errors and application glitches can cause the requests to fail. Event Notifications automatically retries failed requests to provide resiliency to external requests.

For detailed information about retry behavior, including retry attempts, delays, and timeout values, see Retry policy for destinations.

Testing a webhook destination configuration

You can test a webhook destination in the options menu. You can test a destination, whether the provided configuration is correct or not with a single click.

For more information on testing a destination, see Testing Destinations.