Implementing Carrier Rate Deck Integration for Real-Time Call Cost Estimation and Display

How-To-Articles
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Implementing Carrier Rate Deck Integration for Real-Time Call Cost Estimation and Display

What This Guide Covers

This guide details the architecture for ingesting dynamic carrier rate decks into Genesys Cloud CX to calculate real-time call costs. You will configure the integration between external billing APIs, Genesys Architect, and custom UI components to display live cost estimates to supervisors and agents. The end result is a system that prevents budget overruns by providing immediate feedback on call expenditure based on destination, carrier, and duration.

Prerequisites, Roles & Licensing

  • Licensing: Genesys Cloud CX 3 license is required for full Architect capabilities. Custom UI extensions require the Developer role or specific Custom UI permissions.
  • Permissions:
    • Telephony > Trunk > Read to access trunk configurations.
    • Integration > Custom Integration > Edit to create the outbound integration.
    • Architect > Flow > Edit to implement the cost calculation logic.
    • Analytics > Report > Edit if building dashboards around cost data.
  • OAuth Scopes: integration:custom:read, integration:custom:write, telephony:trunk:read.
  • External Dependencies:
    • Access to a Carrier Billing API (e.g., Twilio, Bandwidth, or a private SIP trunk provider REST API) that exposes current rate decks.
    • A middleware layer (AWS Lambda, Azure Function, or Node.js server) to cache rate data and reduce API call latency. Direct calls to carrier APIs from Genesys Architect are discouraged due to timeout risks.

The Implementation Deep-Dive

1. Architecture of the Rate Ingestion Pipeline

The core challenge in real-time cost estimation is latency. Carrier rate decks are large JSON or CSV structures containing thousands of prefixes. Querying this data on every call setup exceeds Genesys API timeouts and degrades call setup times. The solution requires a caching layer.

We deploy a middleware service that fetches the full rate deck from the carrier every 15 minutes (or upon webhook trigger) and stores it in a lightweight key-value store (e.g., Redis) or an in-memory structure. This middleware exposes a single, fast REST endpoint to Genesys: GET /api/v1/rates/cost?prefix={prefix}&carrier={carrier_id}&duration={seconds}.

The Trap: Attempting to load the entire rate deck into a Genesys Architect Script Variable at the start of a flow.
Genesys Script Variables have size limits and serialization overhead. If you attempt to pass a 5MB JSON object into a script variable, the flow will hang or fail with a 500 Internal Server Error. Furthermore, if the rate deck updates, every active call holding that variable retains the stale data until the flow restarts. Always use a stateless lookup pattern via a Custom Integration, not stateful data loading.

Configuring the Custom Integration

  1. Navigate to Admin > Integrations > Custom Integrations.
  2. Click Add Integration.
  3. Name it CarrierRateLookup.
  4. Set the Type to REST.
  5. Define the Base URL of your middleware service (e.g., https://cost-engine.internal.net).
  6. Configure the Authentication method. Use Basic Auth or Bearer Token depending on your middleware security.
  7. Define the Request Template:
    {
  "method": "GET",
  "url": "/api/v1/rates/cost",
  "params": {
    "prefix": "{{prefix}}",
    "carrier": "{{carrier}}",
    "duration": "{{duration}}"
  }
}
  8. Save the integration. Note the Integration ID.

Architectural Reasoning

By isolating the rate lookup to a dedicated Custom Integration, we decouple the telephony flow from the billing logic. If the billing API goes down, the middleware can return a default “error” rate or a cached fallback rate, allowing the call to proceed without blocking the Genesys flow. This pattern ensures high availability of the telephony path even if the cost estimation subsystem degrades.

2. Implementing Real-Time Calculation in Architect

We cannot calculate the exact cost at call setup because the duration is zero. We must calculate the cost incrementally or at call termination. For real-time display, we use a hybrid approach: a rough estimate at setup based on average handle time (AHT), and an exact calculation at call end.

Step 2a: The Setup Phase (Estimation)

At the start of the outbound or inbound flow, we capture the destination number and the assigned trunk.

  1. Add a Set Variable node.
    • Variable: dest_number
    • Value: {{call.to}}
  2. Add a Set Variable node.
    • Variable: carrier_id
    • Value: {{call.trunk_id}} (Note: This assumes you map trunks to carriers. If using dynamic routing, you must track the selected trunk in a prior routing node).
  3. Add a Custom Integration node.
    • Integration: CarrierRateLookup
    • Map prefix to {{substring(dest_number, 0, 7)}} (First 7 digits for LATA/NPA-NXX).
    • Map carrier to {{carrier_id}}.
    • Map duration to 300 (Assume 5 minutes for estimation).
    • Set the response variable to cost_estimate_response.

The Trap: Using the full phone number as the prefix for rate lookup.
Carrier rates are often defined by 3-digit, 5-digit, or 7-digit prefixes. Sending a 10-digit number to a rate engine that expects a 5-digit prefix will result in a “No Match” error, defaulting to a high penalty rate. Always normalize the prefix length based on your carrier’s rate deck structure. Most global rate decks use 5-7 digits for domestic and variable lengths for international.

Step 2b: The Active Call Phase (Real-Time Updates)

To display real-time costs during the call, we cannot rely on Architect alone, as Architect is event-driven and does not support polling. We must push data to the UI.

  1. Enable Event Streaming for the call.
  2. Use a Custom UI extension (React/Vue) subscribed to the call events.
  3. The UI component maintains a local timer. Every second, it calculates:
    const currentSeconds = Math.floor((Date.now() - call.startTimestamp) / 1000);
const ratePerSecond = estimatedRatePerMinute / 60;
const currentCost = currentSeconds * ratePerSecond;
  4. Display currentCost in the agent or supervisor dashboard.

Step 2c: The Teardown Phase (Exact Billing)

When the call ends, we need the exact duration and the exact rate.

  1. Add an On Call End handler in Architect.
  2. Calculate duration: {{call.duration_seconds}}.
  3. Call the CarrierRateLookup integration again with the actual duration.
  4. Store the final cost in a Data Action or send it to an external database (e.g., Snowflake, BigQuery) via another Custom Integration for reporting.

The Trap: Relying solely on call.duration_seconds for billing.
Genesys call.duration_seconds includes hold time, transfer time, and wrap-up time depending on how you define “call.” Billing from carriers usually stops at the moment the SIP BYE is sent. If you have complex flows with holds, your internal cost calculation may diverge from the carrier bill. Always align your duration calculation with the carrier’s definition of “billable seconds.” Usually, this is call.connection_duration excluding hold states, or you must accept the discrepancy and build a reconciliation process.

3. Building the Custom UI Component for Cost Display

Genesys Cloud does not have a native “Cost per Call” widget. We must build a Custom UI Extension.

Step 3a: Scaffold the Extension

Use the Genesys Cloud CLI to create a new extension.

genesys-cloud extension create --name cost-display --type ui

Step 3b: Subscribe to Call Events

In your React component, subscribe to the call stream.

import { useSubscription } from '@genesyscloud/cloud-ui-sdk';

function CostDisplay({ callId }) {
  const [cost, setCost] = useState(0);
  const [rate, setRate] = useState(0);

  // Fetch initial rate from your middleware
  useEffect(() => {
    fetch(`/api/rates?prefix=${call.prefix}`)
      .then(res => res.json())
      .then(data => setRate(data.ratePerMinute));
  }, [callId]);

  // Update cost every second
  useEffect(() => {
    if (!call.startTimestamp) return;
    const interval = setInterval(() => {
      const seconds = Math.floor((Date.now() - call.startTimestamp) / 1000);
      setCost((seconds * rate) / 60);
    }, 1000);
    return () => clearInterval(interval);
  }, [rate, call.startTimestamp]);

  return <div className="cost-badge">${cost.toFixed(2)}</div>;
}

The Trap: Not handling time zone and clock synchronization differences.
The agent’s browser clock may drift from the Genesys server clock. If the UI calculates cost based on Date.now() in the browser, but the final billing is calculated based on server-side call.duration_seconds, there will be a discrepancy. To mitigate this, the UI should request the “current server time” from the middleware or Genesys API at the start of the call and use that as the baseline for calculations, rather than the local browser clock.

Step 3c: Integrate into the Supervisor Dashboard

  1. Deploy the extension.
  2. In Admin > Extensions > UI, configure the placement.
  3. Choose Supervisor Dashboard or Agent Desktop.
  4. Map the component to the call context.

4. Data Persistence and Reconciliation

Real-time display is for operational awareness. For financial accountability, you must store the data.

  1. Create a Data Action in Architect at the end of the flow.
  2. Store: call_id, destination, carrier, duration_seconds, cost, timestamp.
  3. Use a Custom Integration to POST this data to your data warehouse.

The Trap: Storing PII (Personally Identifiable Information) in cost logs.
If you store the full call.to number, you are storing PII. In regulated industries (HIPAA, PCI), this data must be masked or hashed. Store only the prefix used for rating and a hash of the full number, unless you have explicit legal justification and security controls for the full number.

Validation, Edge Cases & Troubleshooting

Edge Case 1: Rate Deck Update During Call

The Failure Condition: A carrier changes rates mid-day. Calls started before the change are billed at the old rate, but the UI displays the new rate (fetched from cache).

The Root Cause: The middleware cache updated, but the call flow already fetched the old rate at setup.

The Solution: Implement a “Rate Version” tag in the middleware response. When the Architect flow fetches the rate at setup, it also fetches the rate_version. At call end, when fetching the final cost, pass the rate_version to ensure the same rate structure is used for billing as was used for estimation. Alternatively, accept the minor variance and treat real-time cost as an estimate, not a bill.

Edge Case 2: Carrier Failover and Rate Mismatch

The Failure Condition: A primary trunk fails, and Genesys fails over to a secondary trunk. The secondary trunk uses a different carrier with a different rate deck. The UI continues to display the cost based on the primary carrier’s rate.

The Root Cause: The UI component subscribed to the initial call.trunk_id but did not listen for trunk_change events.

The Solution: In the Custom UI, subscribe to the call.trunk_id property change. If the trunk ID changes, trigger a new rate fetch from the middleware with the new carrier ID. Update the rate state variable dynamically.

Edge Case 3: International Dialing and Prefix Ambiguity

The Failure Condition: A call is placed to +44 20 7946 0958. The rate deck has a 3-digit prefix rate for +44 and a 7-digit prefix rate for +4420794. The system applies the 3-digit rate, which is cheaper, but the carrier bills at the 7-digit rate.

The Root Cause: The middleware uses a longest-match algorithm for prefixes, but the Architect flow only passes the first 3 digits.

The Solution: Pass the full normalized number to the middleware. The middleware should implement a longest-prefix-match algorithm internally. The Architect flow should not truncate the prefix arbitrarily. Let the middleware determine the most specific rate.

Official References