Conversation API IP Address Change - Action required before March 25, 2026

Shahzad_Ismail — Tue, 10 Mar 2026 09:34:00 GMT

At Sinch Service continuity is our priority for all our customers. To ensure your Conversation API integration runs smoothly, we are proactively notifying you of an important infrastructure change that may require your action before March 25, 2026.

Effective March 25, 2026, the IP addresses associated with Conversation API base URLs will change. This is a global change affecting all regions. The base URLs themselves (for example, https://us.conversation.api.sinch.com) and the source IP addresses used for callbacks and webhooks will remain unchanged. Only the ingress IP addresses for inbound API requests to Sinch are affected.

For more information about these changes and to subscribe for notifications - visit our related Sinch status page: https://status.sinch.com/incidents/y974xxzk7mfv.

Who is affected?

You will need to act before March 25, 2026, if the following applies to your integration:

You have implemented IP whitelisting (allowlisting) rules on your network or firewalls that restrict outbound traffic to specific Sinch IP addresses.
If your integration connects to Conversation API using the documented hostnames and does not restrict outbound traffic by IP address, no action is required.

What action is required?

If you are affected, you must update your firewall rules and/or connection configuration to include the new IP addresses before March 25, 2026:

Environment	FQDN	Old Public IPv4 address	New Public IPv4 address
EU1	eu.conversation.api.sinch.com	34.246.12.78	34.247.10.251
		52.18.1.217	34.243.80.241
		52.50.172.104	63.33.21.26
US1	us.conversation.api.sinch.com	44.196.133.251	52.22.60.183
		52.201.9.233	52.71.26.226
		54.243.120.247	44.221.23.197
BR1	br.conversation.api.sinch.com	177.71.243.105	18.229.217.42
		18.228.234.250	18.230.233.81
		18.229.82.177	54.94.159.24

We recommend completing this change as early as possible to ensure a seamless transition and avoid any potential for service interruption.

What happens if no action is taken?

After the March 25, 2026 deadline, if your systems have IP whitelisting rules that are not updated, your connections will be rejected. This will result in a service disruption for your application's integration.

Important Best Practice Reminder

We strongly recommend that all integrations connect to Sinch APIs via DNS resolution of the documented hostnames (for example, us.conversation.api.sinch.com). The IP addresses underlying our API endpoints can and do change. Using hostnames ensures your integration remains resilient to future infrastructure changes without requiring manual intervention.

If your security policies require IP-based allowlisting, please work with your Account Manager. Additional infrastructure changes will occur, and we will notify you of each one in advance.

We apologize for any inconvenience this may cause and appreciate your understanding as we continue to invest in the reliability and performance of our platform. If you have any questions, please reach out to your Account Manager or contact our support team. We’re always happy to help you.

article Conversation API IP Address Change - Action required before March 25, 2026 in Conversation API

Conversation API IP Address Change - Action required before March 25, 2026

Who is affected?

What action is required?

What happens if no action is taken?

Important Best Practice Reminder