Incident affecting Applications in Development Stage in Europe Central

Update timeline

1. investigating Jul 31, 2026, 08:31 AM UTC

   We are aware of an issue affecting Applications in the Development Stage in Europe Central (Frankfurt). Applications may experience an "upstream request timeout" error, when scaling up. As a workaround, most applications will load after a few minutes. Republishing the application will also sucessfully scale it up within few minutes. Our team is currently investigating its cause. We will provide an update as soon as more details are available.

2. identified Jul 31, 2026, 10:43 AM UTC

   We have identified the cause of the "upstream request timeout" error. Our team has implemented a fix and apps should once again scale up succesfully without errors. We continue to investigate the issue to ensure full recovery. The previously mentioned workaround of republishing your applications remains available during this period. We will provide updates as more information becomes available.

3. monitoring Jul 31, 2026, 03:53 PM UTC

   We continue to monitor the fix implemented earlier this morning to ensure full recovery. Applications should scale up successfully with no errors now. Some latency (seconds) might still be noticed before they fully scale up. We will provide updates as more information becomes available.

4. monitoring Aug 04, 2026, 09:59 AM UTC

   We are continuing to monitor the implemented fix, and no new occurrences have been reported. We will share our next status update by the end of the week.

5. resolved Aug 07, 2026, 08:34 AM UTC

   This issue has been resolved. Following ongoing monitoring, no new occurrences of the issue have been reported. Applications in the Development Stage in Europe Central (Frankfurt) have been scaling up successfully without errors since our fix was implemented.

6. postmortem Aug 07, 2026, 03:40 PM UTC

   On July 31st, 2026, an issue affected applications running in the Development Stage in Europe Central \(Frankfurt\). Applications experienced extended delays \(2–3 minutes\) and timeout errors when starting up from an idle state. The issue lasted approximately a few hours and was detected through customer reports and platform monitoring. During this time, several customers in the region reported difficulties launching their applications in the Development Stage's Runtime. Our investigation identified a memory issue in a critical component responsible for automatically scaling applications based on incoming traffic. This component was consuming excessive memory and restarting repeatedly, which prevented applications from scaling up when first accessed. Our team immediately implemented an operational workaround by increasing resource limits for this component. This mitigation immediately allowed applications to scale up as expected. In parallel, we developed a permanent code fix to address the root cause and deployed it on August 7th. The system remained stable, with no new occurrences during and after the deployment of the permanent fix. To prevent similar issues, OutSystems is improving how we monitor and validate infrastructure configuration to catch memory and resource issues earlier, and we are enhancing our automated scaling components to handle traffic pattern changes more gracefully. We apologise for any disruption caused and thank you for your patience.