Deploying a fully automated AI outbound calling system using Vapi, n8n, and Google Sheets to run batch phone outreach campaigns with real-time result tracking, regional number routing, and intelligent pacing controls.
Client Overview
A sales development team was running outbound phone campaigns manually, with SDRs working through contact lists call by call, logging outcomes in spreadsheets after each conversation, and attempting to maintain consistent pacing across UK and US time zones. The process was slow, expensive in SDR hours, and produced inconsistent data quality — logged outcomes varied by rep, follow-up triggers were missed, and reporting required manual aggregation at the end of each campaign. The team needed to run significantly higher outreach volume without adding headcount, while also improving the consistency of call outcomes and ensuring every result was logged accurately in real time. Regional compliance requirements also meant UK and US numbers needed to be handled through separate routing logic with different calling parameters.
Our Approach
Zentric Solutions built a batch AI outbound calling system on n8n using Vapi as the voice AI layer. Contacts are loaded directly from a structured Google Sheet, validated and normalised on ingestion, and processed in configurable batches with automated pacing controls between each batch to avoid rate limits and maintain call quality. When the workflow is triggered, a contact normalisation step validates and standardises all fields — name formats, phone number structures, and regional codes — before any calls are placed. Contacts are then routed to UK or USA number pools based on country code, with separate Vapi configurations for each region to handle different calling parameters, compliance requirements, and script variations. Each call is placed through the Vapi outbound call API, and results are collected in a batch aggregation step that waits for all calls in the current batch to complete before proceeding. Outcomes — call status, conversation summary, disposition, and any follow-up flags — are written back to the originating Google Sheet row in real time, ensuring the source of truth is always current. A wait-between-batches node introduces configurable delays to maintain sustainable call pacing, followed by a logging step that records batch completion metadata for monitoring. Once all batches are processed, a final summary node compiles campaign-level statistics and delivers a structured report for review.
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