### Answer The documentation doesn't explicitly state a maximum number of tasks per batch call request. However, there's a relevant community report where a user encountered a 400 error when adding 2,035 phone numbers to a batch call, and had to split it into smaller batches (500, then further to 200-300) to get it working. [(1) ]() Based on this, sending 30k tasks in a single API request may exceed platform limits and could result in errors. I'd recommend: 1. Split your batch into smaller chunks — try batches of a few hundred tasks each 2. Use the

trigger_timestamp

parameter to schedule them if needed [(2) ]() The platform does support high-volume batch calling — pricing is $0.005 per dial (20k calls for $100) — and it queues calls without hitting concurrency limits. [(3) ]() [(4) ]() For a definitive answer on the exact task limit per request, I'd suggest reaching out to support: - [Contact Sales]() - Check the [Retell AI GitHub]() Would you like a general answer on best practices for handling large batch API requests?

​ To learn more, see the sources I considered: [[1] Batch calling is having issues](https://discord.com/channels/1186424376300679209/1429681363321094164) [[2] Create Batch Call](https://docs.retellai.com/api-references/create-batch-call) [[3] Batch Calling, New Docs, and More Improvements!](https://www.retellai.com/changelog/batch-calling-new-docs-and-more-improvements) [[4] Streamline Calls with Retell AI’s Batch Dialer | Retell AI](https://www.retellai.com/blog/boost-operation-efficiency-with-retell-ais-batch-calling) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer You can track when batch calls happen using webhooks. [(1) ]() Retell AI supports these webhook events for call tracking: -

call_started

— triggered when a new call begins -

call_ended

— triggered when a call completes, transfers, or encounters an error -

call_analyzed

— triggered when call analysis is complete You can set up a webhook URL at the agent level using the

webhook_url

parameter to receive real-time notifications as each call in your batch starts and ends. [(2) ]() Additionally, you can monitor batch call progress through the dashboard, which shows metrics like: [(3) ]() - Sent — total calls sent from the batch - Picked Up — number of calls answered - Successful — calls completed based on predefined criteria You can also click the history icon in the Batch Call tab to view call details for each individual call in the batch. For programmatic tracking, you can use the [List Calls]() endpoint to retrieve call details including

start_timestamp

,

end_timestamp

, and

call_status

. [(4) ]()

​ To learn more, see the sources I considered: [[1] Webhook Overview](https://docs.retellai.com/features/webhook-overview) [[2] Get Agent Versions](https://docs.retellai.com/api-references/get-agent-versions) [[3] Create Batch calls](https://docs.retellai.com/deploy/make-batch-call) [[4] List Calls](https://docs.retellai.com/api-references/list-calls) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer Once your batch is scheduled, you have a few options to track how many calls happened and when: *1. Webhooks (Real-time tracking) * Set up webhooks to receive instant notifications for each call. [(1) ]() -

call_started

— when a call connects -

call_ended

— final status and duration -

call_analyzed

— transcript and analysis ready Each webhook payload includes

start_timestamp

and

end_timestamp

(milliseconds since epoch) , so you can log exactly when each call occurred. *2. List Calls API (Query by time range) * Use the List Calls API with

filter_criteria

to query calls within a specific time window: [(2) ]()

javascript
import Retell from 'retell-sdk';
const client = new Retell({
  apiKey: 'YOUR_RETELL_API_KEY',
}) ;
const callResponses = await client.call.list() ;
console.log(callResponses) ;

You can filter by

start_timestamp

with

upper_threshold

and

lower_threshold

to get calls within a specific hour. 3. Analytics Dashboard The Analytics dashboard provides real-time insights and you can create charts to visualize call volumes and patterns over time. [(3) ]() However, the documentation doesn't specify a way to predict exactly when calls will be placed within a batch after the trigger timestamp — the system queues and processes them based on concurrency. You'd need to monitor them as they happen using the methods above.

​ To learn more, see the sources I considered: [[1] Webhook Overview](https://docs.retellai.com/features/webhook-overview) [[2] List Calls](https://docs.retellai.com/api-references/list-calls) [[3] Get analytics insight](https://docs.retellai.com/features/analytics-dashboard) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer No, calls do not happen simultaneously. The batch dialer queues calls and initiates them as concurrency slots become available. [(1) ]() Specifically: - Ongoing status means the batch is currently in progress, with calls initiated as concurrency slots become available [(2) ]() - The system ensures smooth operation without hitting concurrency limits [(1) ]() So when the

trigger_timestamp

is reached, the batch begins processing, but calls are dispatched based on your account's concurrency capacity rather than all at once. The exact rate depends on your concurrency limits and how quickly previous calls complete. The documentation doesn't specify an exact calls-per-hour rate or provide an API parameter to control pacing. You'd need to monitor call progress via webhooks or the List Calls API to track actual throughput.

​ To learn more, see the sources I considered: [[1] Streamline Calls with Retell AI’s Batch Dialer | Retell AI](https://www.retellai.com/blog/boost-operation-efficiency-with-retell-ais-batch-calling) [[2] Create Batch calls](https://docs.retellai.com/deploy/make-batch-call) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer The available documentation doesn't provide information on how to pause, cancel, or stall an in-progress batch call via API. The sources describe how to create and schedule batch calls, and how to monitor them, but don't document an endpoint or method to stop or pause calls once a batch has started. Check out these potentially useful sources: - [Streamline Calls with Retell AI's Batch Dialer]() - [List Calls API]() - [Contact Sales]() For a definitive answer on stopping or pausing batch calls, I'd recommend reaching out to Retell AI support directly. Would you like me to try to provide a general answer based on my knowledge instead?

message has been deleted

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

Thanks for the feedback, glad I was helpful.