Hello, We sent a batch of 300 contacts to Vapi. For each contact, Vapi returned a call ID. However, only 85 calls were actually processed. The remaining 215 calls were put into a scheduled state but did not proceed further. There are no call logs, call attempts, or failure reasons visible for these calls in the call logs. Could you please help us understand: Why these 215 calls were scheduled but not executed Where scheduled calls can be checked (e.g. schedule logs, queue view, or any other endpoint), as we currently do not see anything related to these calls in the call logs What happens internally to calls that remain in a scheduled state (timeouts, retries, expiry, etc.) Whether there are any internal limits, throttling, or queue constraints that could cause this behavior What needs to be done on our side to reliably process large batches (e.g. 300 contacts) without calls getting stuck without logs We would appreciate any guidance or documentation references on how scheduling and large batch handling works in Vapi.

Actionable Next Step: To address scheduled calls not processing due to concurrency limits, manually trigger queue processing by calling the

/process-queue

endpoint on your server:

bash
curl -X POST https://your-server.com/process-queue

This will attempt to process any queued/scheduled calls as soon as capacity is available. Also, verify your concurrency limit in the [Vapi Dashboard](https://dashboard.vapi.ai/settings/billing) to ensure it matches your batch size and adjust as needed for large campaigns ([documentation](https://docs.vapi.ai/calls/call-queue-management)). Source: - [Call queue management with Twilio](https://docs.vapi.ai/calls/call-queue-management)

why is there no logs for the schedule calls

Hi SJ, When working with Vapi, the concurrency limit directly affects how many calls can be active simultaneously. Even if you send calls in batches of 10, the limit means only 10 calls can process at once; the rest are queued. If the remaining scheduled calls aren't proceeding, it indicates they're waiting for available slots. Scheduled calls might not show in logs if there are backend constraints or your concurrency is restricted. Make sure to check the [Vapi Dashboard](https://dashboard.vapi.ai/settings/billing) for your concurrency settings to ensure they align with your campaign size. Additionally, employing a call queue management system using [Twilio](https://docs.vapi.ai/calls/call-queue-management) can help manage large volumes by processing queued calls as slots open up. For your issues: - Not executing scheduled calls: Ensure the concurrency is correctly set up to handle your batch. Use

/process-queue

on your server to manually trigger processing queued calls. - Scheduled call visibility: Currently, some call logs might not display scheduled state transitions, especially if they haven't moved to execution. Monitoring via the Vapi API or querying analytics data may give additional visibility. Refer to the [Outbound Campaigns Overview](https://docs.vapi.ai/outbound-campaigns/overview) for more strategies on managing large batches efficiently.