Build Usage-based Pricing like Vapi.ai

• Feature Name: SMS / Chat Hosting
• Feature Lookup_key: sms_chat_hosting (immutable, unique identifier)
• Feature Type: Metered
• Event Name: sms.chat.message (must match exactly when sending events)
• Aggregation Method: Sum
• Aggregation Field: messages
• Unit: message or msg
• Description: Vapi hosting cost for SMS and chat messages - covers message delivery, session handling, and conversational state management

Note: The Event Name must match exactly when you send usage events via API. Save these event names for later use.

• Plan Name: Pay As You Go
• Lookup Key: pay_as_you_go (immutable, unique identifier)
• Plan Description: Usage-based pricing plan with flat fees for call minutes and SMS/chat messages
• Click Next to proceed to charge configuration

• Select Metered Feature: SMS / Chat Hosting (sms_chat_hosting)
• Billing Currency: USD
• Billing Period: Monthly
• Billing Model: Flat Fee
• Price per Unit: 0.005 (per message)
• Billing Timing: Arrears Billing (bill at end of cycle)
• Click Add to save this charge

• Customer Name: Acme Corporation (or your customer’s name)
• External ID: cust_acme_001 (unique identifier from your system)

• Email: Customer’s email address
• Phone: Customer’s phone number
• Address: Customer’s billing address

Important: The External ID is what you’ll use when sending usage events. Make sure it matches exactly.

• Select Plan: Choose Pay As You Go from the dropdown
• Subscription Start Date: Select the start date for billing (e.g., today’s date)
• Subscription End Date: Leave as “Forever” for ongoing subscriptions, or set a specific end date
• Billing Cycle: This determines when billing cycles start (usually the start date)

• All recurring charges (if any)
• Usage-based charges that will be billed based on consumption
• Estimated costs for the billing period

POST https://api.cloud.flexprice.io/v1/events

x-api-key: <your_api_key>

curl --request POST \
  --url https://api.cloud.flexprice.io/v1/events \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <your_api_key>' \
  --data '{
    "event_name": "sms.chat.message",
    "external_customer_id": "cust_acme_001",
    "properties": {
      "messages": 1
    },
    "event_id": "evt_sms_67890",
    "timestamp": "2025-01-15T10:35:00.000Z",
    "source": "vapi-platform"
  }'

curl --request POST \
  --url https://api.cloud.flexprice.io/v1/events/bulk \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <your_api_key>' \
  --data '{
    "events": [
      {
        "event_name": "call.minutes",
        "external_customer_id": "cust_acme_001",
        "properties": { "minutes": 10 },
        "source": "vapi-platform"
      },
      {
        "event_name": "sms.chat.message",
        "external_customer_id": "cust_acme_001",
        "properties": { "messages": 3 },
        "source": "vapi-platform"
      }
    ]
  }'

• event_name (required): Must match your feature’s Event Name exactly (call.minutes or sms.chat.message)
• external_customer_id (required): Must match the customer’s External ID (cust_acme_001)
• properties (required): Contains the aggregation field value
  • For Call Minutes: {"minutes": <number>}
  • For SMS/Chat: {"messages": <number>}
• event_id (optional): Your unique identifier for the event
• timestamp (optional): ISO 8601 UTC timestamp. If omitted, server time is used
• source (optional): Origin of the event (e.g., “vapi-platform”, “api”)

{
  "event_id": "event_01K389J4M1F1NZG6XP0AMD6J52",
  "message": "Event accepted for processing"
}

1. Go to Flexprice Dashboard → Usage Tracking → Event Debugger

• Event ID: Unique identifier for each event
• Event Name: The feature being tracked (call.minutes or sms.chat.message)
• Customer Lookup Key: Customer’s External ID
• Source: Origin of the event
• Timestamp: When the event occurred

{
  "id": "event_01",
  "external_customer_id": "cust_acme_001",
  "event_name": "call.minutes",
  "timestamp": "2025-01-15T10:30:00.000Z",
  "properties": {
    "minutes": 5.5
  },
  "source": "vapi-platform"
}

• Filter by Event Name: event_name contains "call.minutes"
• Filter by Customer: external_customer_id contains "cust_acme_001"
• Filter by Time Range: Set Start Time and End Time
• Filter by Source: source contains "vapi-platform"

1. Check that events appear in the Event Debugger shortly after sending
2. Verify the event payload matches what you sent
3. Confirm the external_customer_id matches your customer
4. Ensure event_name matches your feature configuration exactly
5. Check that properties contain the correct aggregation field values