Sinch Community

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. ... View more

Sinch Build Customer: if your 10DLC campaign has been rejected, do not be concerned, this means that you must address the list of corrective actions provided with the rejection in the Notes section of the campaign decision.   To resubmit your campaign, follow the simple steps outlined below: Log in to the Sinch Build Dashboard. Select SMS from the left menu and click the US 10DLC Campaigns option. The 10 DLC Campaigns page is displayed:   The REQUESTS tab shows you the list of campaigns you have submitted and not yet approved. Select your campaign from the list (in the example above the rejected campaign is highlighted in blue). To view the details of why the campaign was rejected, click the open icon   corresponding to the selected campaign. The Campaign details are displayed. Scroll down to the Notes section to see the rejection information: This section displays detailed reasons for why the campaign was rejected along with accompanying explanatory links. Note this information carefully as these points will need to be addressed before you can resubmit the campaign. You cannot edit the existing campaign. You will need to "clone" and fix any issues in the cloned campaign, thus as mentioned, note the "corrective actions needed", so you can fix them in the cloned campaign. Scroll up to the top of the page and click the BACK TO 10 DLC CAMPAIGN LIST link. The 10 DLC Campaigns page is displayed. Scroll down to the Your Campaign Requests list: Select your campaign from the list (in the example above the rejected campaign is highlighted in blue). Click the clone icon   corresponding to the selected campaign. The Copy campaign dialog is displayed: All your data from your existing rejected campaign will be copied into the new campaign, so you do not need to re-enter all the data. Refer to the 10DLC Campaign Registration: Required Fields and Explanations article for detailed information about the fields on this form. Edit the campaign fields to address the list of corrective actions provided with the rejection, which you noted down from the previous step. If you need any assistance in understanding how to resolve campaign rejections, please refer to the following help article: 10DLC Campaign Rejection Codes - Sinch Community - 15722 After making the required changes, click Submit campaign to resubmit the corrected campaign for re-review by Sinch.   Important Note: Sinch Build campaign review rejections are based on an AI algorithm and if you disagree with the reasons for the rejection, please click the dispute review decision button within the clone campaign screen and your campaign will be routed for manual review. Related articles: 10DLC Campaign Registration: Required Fields and Explanations 10DLC Campaign Rejection Codes. ... View more