What happened

A change to our internal telephony configuration was rolled out to production and introduced an unexpected fault in call routing.

What was affected

• EU region: calls failed from 10:32–10:44 UTC (12:32–12:44 CEST) — 12 minutes.

• US region: calls failed from 10:33–10:42 UTC (12:33–12:42 CEST) — 9 minutes.

• All regions: warm transfers failed intermittently from 07:00–10:42 UTC (09:00–12:42 CEST) — 3 hours 42 minutes.

All services were fully restored by 10:44 UTC. No customer data was affected.

What we're doing next

We have rolled back the change and added a pre-deployment check to catch this class of routing fault before it reaches production. A full root cause analysis will be published here shortly.

We're sorry for the disruption.

Maintenance has completed

What happened

An internal configuration change restricted which AI models the Synthflow platform was permitted to call. The restriction was applied more broadly than intended and blocked the models used by our post-call processing pipeline.

As a result, AI-generated post-call outputs failed to produce calls completed during the window. The configuration was reverted at 11:10 UTC and all functionality returned to normal immediately.

What was affected

Calls placed and received during this window connected, ran, and completed normally. The failures were confined to AI processing within the post call webhook that runs after a call ends.

The following were affected:

Info extractors: Extracted variables not populated

Call summary: Not generated

LLM-as-a-judge: Did not run

Custom evaluations: Did not run

Post-call SMS actions: Not triggered or sent

If you consume the post-call webhook, the webhook is still fired and delivered but these fields were empty or missing in the payload for affected calls.

What was not affected

• Inbound and outbound call connectivity

• Live conversation with your agents during the call

• Call recordings and audio

• Transcripts

• Post-call webhook delivery itself (the webhook fired as normal)

• Call logs, billing records, and the dashboard

What you should do

If your workflows depend on extracted variables, summaries, or post-call SMS for calls completed between 08:20 and 11:10 UTC on 7 August, treat those records as incomplete. Recordings and transcripts for those calls are intact.

What we're changing

We've completed an internal review of this incident and are making improvements in three areas:

• Detection — strengthening monitoring so issues of this type are surfaced and acted on faster.

• Change controls — tightening the review and approval process for platform configuration changes.

• Impact review — improving how we assess the downstream reach of a change before it is applied.

Maintenance has completed

Maintenance has completed

Dear Customer,

Our engineers will be performing essential maintenance on our telephony infrastructure in the upcoming change control period. During this one-hour window, some calls may experience a brief interruption of up to ten minutes. We will provide real-time updates on our status page throughout the maintenance period.

Regions affected:

• US

• EU

• Global

Kind Regards,

Synthflow Team.

Dear Customer,

Our engineers will be performing essential maintenance on our telephony infrastructure in the upcoming change control period. During this one-hour window, some calls may experience a brief interruption of up to ten minutes.

We will provide real-time updates on our status page throughout the maintenance period.

Regions affected:

• US

• EU

• Global

Kind Regards,

Synthflow Team.

[2026-07-08T1022.000Z UTC] Maintenance ended

Dear Customer,

Our engineers will be performing essential maintenance on our telephony infrastructure in the upcoming change control period. During this one-hour window, some calls may experience a brief interruption of up to ten minutes. We will provide real-time updates on our status page throughout the maintenance period.

Regions affected:

• US

• EU

• Global

Kind Regards,

Synthflow Team.

[2026-06-29T1031.000Z UTC] Maintenance ended

Dear Customer,

Our engineers will be performing essential maintenance on our telephony infrastructure in the upcoming change control period. During this one-hour window, some calls may experience a brief interruption of up to ten minutes. We will provide real-time updates on our status page throughout the maintenance period.

Regions affected:

• US

• EU

Kind Regards,

Synthflow Team.

[2026-06-01T1026.000Z UTC] Maintenance ended

Dear Customer,

Our engineers will be performing essential maintenance on our telephony infrastructure in the upcoming change control period. During this one-hour window, some calls may experience a brief interruption of up to ten minutes. We will provide real-time updates on our status page throughout the maintenance period.

Region affected: Global region only.

Kind Regards,

Synthflow Team.

[2026-05-29T1052.000Z UTC] Maintenance ended

Dear Customer,

Our engineers will be performing essential maintenance on our telephony infrastructure in the upcoming change control period. During this one-hour window, some calls may experience a brief interruption of up to ten minutes.

We will provide real-time updates on our status page throughout the maintenance period.

Regions affected:

US EU

Kind Regards, Synthflow Team.

[2026-05-28T1007.000Z UTC] Maintenance ended

We will be performing scheduled infrastructure maintenance. During this window, ongoing voice calls may experience brief disruptions lasting approximately 10–15 minutes.

[2026-05-26T0920.534Z UTC] Our scheduled infrastructure maintenance has been successfully completed. All services are fully operational and performing as expected.

[2026-05-26T1000.000Z UTC] Maintenance ended

Our team will be performing essential maintenance on our telephony infrastructure. During this one-hour window, some calls may experience a brief interruption of up to 15 minutes.

We will provide real-time updates on our status page throughout the maintenance period.

[2026-05-12T1017.000Z UTC] Maintenance ended

Our team will be performing essential maintenance on our telephony infrastructure. During this one-hour window, some calls may experience a brief interruption of up to ten minutes.

We will provide real-time updates on our status page throughout the maintenance period.

[2026-05-11T1040.000Z UTC] Maintenance ended

Our team will be performing essential maintenance on our telephony infrastructure. During this one-hour window, some calls may experience a brief interruption of up to ten minutes.

We will provide real-time updates on our status page throughout the maintenance period.

[2026-04-20T0927.000Z UTC] Maintenance ended

Our team will be performing essential maintenance on our telephony infrastructure. During this one-hour window, some calls may experience a brief interruption of up to ten minutes.

We will provide real-time updates on our status page throughout the maintenance period.

-- US workspaces only -- Our team will be performing essential maintenance on our telephony infrastructure. During this one-hour window, some calls may experience a brief interruption of up to ten minutes.

Subject Line Planned Maintenance: Infrastructure Optimization

What We're Doing: We will be performing routine infrastructure optimization to improve internal routing efficiency and overall system reliability. IP addresses of some public endpoints may change.

When Scheduled Window: March 23d, 13:00–14:00 CET Expected Actual Impact Duration: 0–5 minutes during the switchover.

Downtime: Up to 5 minutes due to IP address changes and DNS cache invalidation.

Customer-facing services: API requests may experience latency spikes, packet drops, or HTTP 502/503 errors during the switchover period.

API behavior: Transient errors expected during the 1–5 minute window. Retry logic with exponential backoff is recommended.

Data & queries: This change does not affect customer data, queries, or runtime behavior.

Other services affected: None

What You Need to Do: If your integration does not already handle transient API errors, we recommend ensuring retry logic is in place before the maintenance window.

Monitoring & Safety: Systems will be actively monitored during the update. Rollback procedures are in place if needed. We expect to complete this well within the scheduled window.

Our team will be performing essential maintenance on our telephony infrastructure. During this one-hour window, some calls may experience a brief interruption of up to ten minutes.

We will provide real-time updates on our status page throughout the maintenance period.

Our team will be performing essential maintenance on our telephony infrastructure. During the scheduled maintenance window, some calls may fail to connect for brief periods of up to 1–5 minutes total.

We will provide real-time updates on our status page throughout the maintenance period.

Subject Line Planned Maintenance: Infrastructure Optimization

What We're Doing We will be performing routine infrastructure optimization to improve internal routing efficiency and overall system reliability. This includes updates to our network controller configuration to ensure better performance and resource utilization going forward.

When Scheduled Window: March 11th, 10:00–11:00 CET Expected Actual Impact Duration: 2–5 minutes during the switchover.

Impact

Downtime: Brief downtime expected during the switchover — estimated 2–5 minutes Customer-facing services: API requests may experience latency spikes, packet drops, or HTTP 502/503 errors during the switchover period API behavior: Transient errors expected during the 2–5 minute window. Retry logic with exponential backoff is recommended. Data & queries: This change does not affect customer data, queries, or runtime behavior Other services affected: None

What You Need to Do If your integration does not already handle transient API errors, we recommend ensuring retry logic is in place before the maintenance window.

Monitoring & Safety

Systems will be actively monitored during the update Rollback procedures are in place if needed We expect to complete this well within the scheduled window

Our team will be performing essential maintenance on our telephony infrastructure. During this one-hour window, small amount of calls may experience a brief interruption of up to ten minutes.

We will provide real-time updates on our status page throughout the maintenance per

Our team will be performing essential maintenance on our telephony infrastructure. During this one-hour window, some calls may experience a brief interruption of up to ten minutes.

We will provide real-time updates on our status page throughout the maintenance period.

Date: February 11, 2026 Time: 08:00 CET Expected Duration: 1-10 minutes

One of our third-party vendors is performing scheduled maintenance on infrastructure that supports our Knowledge Base system. During this time, Knowledge Base search and retrieval features may be temporarily unavailable or experience brief interruptions. We apologize for any inconvenience.

Our team will be performing essential maintenance on our telephony infrastructure. During this one-hour window, some calls may experience a brief interruption of up to ten minutes.

We will provide real-time updates on our status page throughout the maintenance period.

What We’re Doing: We will be performing scheduled infrastructure maintenance to migrate part of production workloads to a new, optimized GKE node pool. This change is based on observed resource utilization and is intended to improve cost efficiency while maintaining current performance and reliability.

When: Scheduled Window: 02-04-2026, 10:00 AM – 11:00 AM CET Expected Actual Impact Duration: Minimal; up to 10–15 minutes during the maintenance window

Impact: Downtime: No planned downtime; brief, intermittent service degradation is possible during pod rescheduling

Customer-facing services: API services may experience short-lived latency or transient errors

Data & requests: No data loss expected; requests affected during the migration may need to be retried

API behavior: API endpoints may return temporary errors during pod restarts

Other services: All other platform services remain unaffected

What You Need to Do: No action is required on your end. If you encounter temporary issues during the maintenance window, please retry after a few minutes. Normal operation will resume once the migration is complete.

Monitoring & Safety: Systems will be actively monitored throughout the maintenance window.

Rolling restarts will be used to minimize impact.

QA validation will be performed after migration.

Rollback procedures are in place if any issues are detected

Rollback Plan: If issues are identified before decommissioning the existing node pool:

Deployments will be reverted to the previous node pool configuration.

Pods will be rescheduled back to the original nodes.

QA re-verification will be performed before proceeding further.

What We're Doing: We will be performing scheduled maintenance on our knowledge base infrastructure to improve system reliability and performance. During this window, our engineering team will apply updates that may temporarily affect knowledge base availability.

When: Scheduled Window: 02-02-2026 10:00AM CET-11:00AM CET Expected Actual Impact Duration: Up to 15 minutes during the maintenance window

Impact: Downtime: Knowledge base services may experience intermittent availability Customer-facing services: Knowledge base search and retrieval may be temporarily unavailable or return limited results Data & queries: No data loss expected; queries submitted during maintenance may need to be retried API behavior: Knowledge base API endpoints may return errors or degraded responses during the maintenance window Other services affected: Core platform services remain unaffected

What You Need to Do: Nothing is required on your end. If you experience issues accessing the knowledge base during the maintenance window, please wait a few minutes and retry. Normal service will resume once maintenance is complete.

Monitoring & Safety: Systems will be actively monitored throughout the maintenance window. Rollback procedures are in place if needed. We will update the status page if the window extends beyond the scheduled time.

Our team will be performing essential maintenance on our telephony infrastructure. During this one-hour window, some calls may experience a brief interruption of up to five minutes.

We will provide real-time updates on our status page throughout the maintenance period.

We will be performing a scheduled maintenance to deploy updates to the Public API.

During this window, short-lived service interruptions, increased latency, or transient errors may occur while the changes are rolled out and systems are stabilized.

Affected APIs:

• /v2/calls

Our team will be performing essential maintenance on our telephony infrastructure. During this one-hour window, some calls may experience a brief interruption of up to five minutes.

We will provide real-time updates on our status page throughout the maintenance period.

Our team will be performing essential maintenance on our infrastructure during this period to ensure continued reliability, performance, and security of our services.

We do not expect any system downtime or service degradation while this work is being carried out. All services should continue to operate as normal.

We will provide real-time updates and any relevant information on our status page throughout the maintenance window, should anything change.

Our team will be performing essential maintenance on our infrastructure during this period to ensure continued reliability, performance, and security of our services.

We do not expect any system downtime or service degradation while this work is being carried out. All services should continue to operate as normal.

We will provide real-time updates and any relevant information on our status page throughout the maintenance window, should anything change.

Description

When: 13 Jan 2026, 07:00 – 07:15 AM CET

What we’re doing: We will apply a small update to optimize database performance.

Impact:

Postgres is HA and remains fully available throughout.

No downtime is expected.

API may experience very brief delays (a few seconds at most).

Monitoring & Safety:

Systems will be actively monitored during the update.

Rollback procedures are in place if needed.

Our team will be performing essential maintenance on our telephony infrastructure. During this one-hour window, some calls may experience a brief interruption of up to five minutes.

We will provide real-time updates on our status page throughout the maintenance period.

Our team will be performing essential maintenance on our telephony infrastructure. During this one-hour window, some calls may experience a brief interruption of up to five minutes.

We will provide real-time updates on our status page throughout the maintenance period.

Our team will be performing essential maintenance on our telephony infrastructure. During this one-hour window, some calls may experience a brief interruption of up to five minutes.

We will provide real-time updates on our status page throughout the maintenance period.

The following two endpoints will be unavailable today while we perform maintenance:

• https://api.synthflow.ai/v2/logs

• https://api.synthflow.ai/v2/logs/:webhook_log_id

We are updating our DNS management configuration. There is a very low chance for temporary DNS entry deletions of <5min length

Our team will be performing essential maintenance on our telephony infrastructure. During this one-hour window, some calls may experience a brief interruption of up to five minutes.

We will provide real-time updates on our status page throughout the maintenance period.

Our team will be performing essential maintenance on our telephony infrastructure. During this one-hour window, some calls may experience a brief interruption of up to five minutes.

We will provide real-time updates on our status page throughout the maintenance period.

[2025-12-04T0952.636Z UTC] We have postpone this maintenance window. We will announce another update when it is being rescheduled.

We are performing scheduled improvements on the Synthflow.ai website to enhance performance and reliability.

[2025-09-11T1036.248Z UTC] Completed – Synthflow.ai Website Improvements

The scheduled improvements on Synthflow.ai have been successfully completed. All systems are operational, and monitoring has resumed.

We are performing scheduled improvements on the Synthflow.ai website to enhance performance and reliability.

[2025-09-09T1545.152Z UTC] Completed – Synthflow.ai Website Improvements

The scheduled improvements on Synthflow.ai have been successfully completed. All systems are operational, and monitoring has resumed.

Our DevOps team will be performing essential server maintenance on Monday, July 28th, between 10:00 AM and 11:00 AM CEST.

📞 Impact: During this window, calls to and from the Synthflow platform may be briefly unavailable, with potential call drops or failures. ⏱️ Expected Disruption: Any interruptions will be short-lived, lasting no more than 5 minutes. ✅ All other system functions will remain unaffected. 🛠️ No action is required on your part.

We appreciate your understanding as we work to ensure continued platform stability and performance.

🔄 We will keep this status page updated throughout the maintenance window.

🚧 Scheduled Maintenance Notice – Saturday, 12 July at 9:00 AM CET / 3:00 AM ET

We will be performing an infrastructure migration on Saturday, 12 July, starting at 9:00 AM CET (3:00 AM ET) for about 3 hours.

This update affects the Actions and Agents backend as well as their User Interfaces. The upgrade is part of our ongoing work to improve performance, reliability, and scalability across the Synthflow platform.

📞 Temporary Impact

• During the maintenance window, you may experience temporary call drops or interruptions.

❗ Impacted Systems

• Actions backend & UI

• Agents backend & UI

✅ No action is required on your end.

• We’re working to minimize downtime and restore full service as quickly as possible.

Thank you for your patience and continued support. – The Synthflow AI Team

We’re rolling out an update on Monday, 26 May, from 1000am CET (400am ET).

During this time, inbound calls to the Synthflow platform may be unavailable. You may experience temporary call drops or failures during this window.

✅ No other parts of the system will be affected. 🛠️ No action is required on your end.

Thank you for your patience! The Synthflow AI Team

[2025-05-26T0831.127Z UTC] ✅ Maintenance Complete The scheduled maintenance on Monday, 26 May, from 10:00–11:00am CET has been successfully completed.

📞 All systems are operating normally. ✅ No further impact is expected. 🛠️ No action is needed on your end.

We’re rolling out an update on Thursday, 22 May, from 1000am CET (400am ET).

During this time, inbound calls to the Synthflow platform may be unavailable. You may experience temporary call drops or failures during this window.

✅ No other parts of the system will be affected. 🛠️ No action is required on your end.

Thank you for your patience! The Synthflow AI Team

[2025-05-22T0815.751Z UTC] Status: Today’s maintenance was postponed - all services remained fully operational.

We’ve rescheduled the deployment for Monday, 26 May 2025, 10:00 – 11:00 CET (04:00 – 05:00 ET).

On [Date], we performed a routine update to the DNS records for api.synthflow.ai. The update involved modifying the A/CNAME records to point to the new IP addresses or services required for the API. This ensures that requests to api.synthflow.ai are properly routed to the updated infrastructure.

Service Incident Report — US Voice Service Disruption

Date: July 6, 2026

Status: Resolved

Summary

On July 6, 2026, our US voice service experienced a brief disruption lasting approximately 18 minutes. During this window, calls to and from US-based voice agents failed to connect. The issue has been fully resolved, and all services have returned to normal operation.

What happened

During planned maintenance on our US infrastructure, a routine cleanup step inadvertently removed a network component that our US telephony service depended on. This severed the connection our call-routing system needed to handle calls, causing them to fail to connect.

Impact

• Duration: Approximately 18 minutes

• Region affected: US only. Our EU and global regions were not affected.

• Effect: Inbound and outbound calls to US voice agents did not connect during the affected window. All EU and global traffic was unaffected.

Resolution

Our engineering team identified the cause quickly and restored the connection, after which calls recovered immediately.

Preventing recurrence

We take reliability seriously and have already begun work to prevent this from happening again, including:

• Reviewing our infrastructure configuration to remove reliance on any undocumented dependencies

• Introducing additional review and safeguards for changes to production systems

• Adopting a stricter decommissioning checklist that verifies real usage before any shared infrastructure is removed

We apologize for any disruption this may have caused and appreciate your understanding. If you have any questions or noticed continued issues, please reach out to our support team.

June 16, 2026 Synthflow RCA

**Increased Rate Limiting (HTTP 429\) in the Synthflow API**

**Summary**

On June 16, 2026, we experienced a significant increase in overall traffic, which triggered Synthflow’s service-wide rate limiting rules. Users of the Synthflow API would have experienced HTTP 429 Too Many Requests errors. Our service-wide rate limits were set too low for historical purposes. We increased our service-wide rate limits and we are planning further improvements to monitoring and rate limiting.

**Customer impact**

From 18:39-20:48 UTC on June 16, 2026, customers experienced intermittent rate limiting when making API requests or using the user interface. Phone calls were unaffected.

**Root cause**

Synthflow’s rate limits have been in place for more than 6 months as-is. When a request is sent to Synthflow, the request routes through Cloudflare, then GCP Cloud Armor, then various internal Synthflow components. Within this pipeline, Cloudflare IPs were treated as the originating traffic IP. As a result, rate limits were applied across the service rather than per IP. Similarly, we relaxed the time windows within our policies to match traffic patterns.

The combination of limiting by Cloudflare IPs instead of originating IPs and an increase in traffic caused rate limits to trigger for multiple customers during the increase in traffic. The configuration changes during the incident allowed acceptable traffic to return to normal rather than being rate limited.

**Next Steps**

We apologize for the challenges this service-wide limitation caused for you. We are continuing to work to ensure we have the right limits in place to ensure continued high levels of service availability. We are taking the following next steps to improve our service level protections:

• Measure and install limits that match current traffic patterns.

• Monitor shifts in traffic and how rate limits should be applied on an ongoing basis.

• Verify all changes to rate limiting go through our standard change management process (done).

• Relax time window for applying rate limits to allow for more traffic. (done)

• Update our rate limiting to properly use originating IPs. (done)

Resolved

The issue has been resolved.

This issue has been resolved.