Case study 05Voice infrastructure

Genius Dialer

Built a multi-tenant browser-based calling system with Twilio Voice SDK, reliable call tracking, recording storage, real-time status updates, and usage-based billing.

Twilio Voice SDKFastAPIMulti-tenantAmazon S3WebhooksGHLUsage billing

Dual-leg

call lifecycle tracking

Real time

status webhook processing

Isolated

voice webhook service

Context

System context.

Background

Genius Dialer gives clients a complete calling workflow inside the browser. Each tenant needs isolated Twilio resources, accurate call state, durable recordings, and billing that reflects actual usage through the GHL wallet.

Challenge

Voice events cannot depend on the availability or workload of the main application. The system needed to track both legs of every call, preserve recordings and status updates, and complete billing-related processing without disruptions elsewhere affecting active client calls or their data.

Architecture

Architecture and implementation.

Current

Resilient multi-tenant calling

Production

Twilio handles browser-based voice for isolated tenant subaccounts, while a dedicated FastAPI service processes call events, recording storage, and usage billing independently of the main application.

Call flow

Browser dialerTwilio Voice SDK

Twiliotenant subaccount

Call legsdual-leg tracking

Client calllive voice session

Event and data flow

Twilio webhooksstatus + recordings

FastAPI serviceisolated processing

Amazon S3recording storage

GHL walletusage-based billing

Multi-tenant Twilio provisioning

Provisioned a dedicated Twilio subaccount for each tenant to keep calling configuration, activity, and usage isolated.

Dual-leg call tracking

Tracked both sides of each call and processed real-time status webhooks so the browser experience reflected the complete call lifecycle.

Durable recording storage

Captured call recordings and stored them in Amazon S3 so they remained available independently of Twilio's transient delivery flow.

Isolated webhook service

Deployed a separate FastAPI microservice for low-latency Twilio webhooks, isolating active calls and call data from downtime in the main server or other services.

Usage-based wallet billing

Connected measured call usage to the GHL wallet so each tenant could be billed through the product's existing account workflow.

Outcome

Results.

Delivered a full browser-based calling workflow with real-time call status.
Isolated tenant calling resources through Twilio subaccounts.
Protected active call processing from downtime in the main application and adjacent services.
Preserved call recordings in S3 and connected usage to GHL wallet billing.

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