AzureAzure Web PubSubApplication Integration

`azurerm_web_pubsub` cost estimation

Managed real-time messaging over WebSockets with a pub/sub model. Priced per unit per day by tier, with included connections and messages per unit.

An azurerm_web_pubsub provides managed real-time messaging over WebSockets using a publish/subscribe model, for live dashboards, chat, collaborative apps, and notifications. It's the sibling of Azure SignalR, with a more protocol-agnostic WebSocket focus, and is priced the same way: per capacity unit per day.

The Standard tier is roughly $1.61/unit-day, with each unit including 1,000 concurrent connections and 1 million messages/day. Premium runs about $2.00/unit-day and adds availability-zone redundancy and autoscaling. The Free tier costs nothing with caps suitable for development (20 connections). Scaling is by adding units, so cost is linear in capacity.

c3x reads the sku and capacity and prices unit-days at roughly 30.4 days/month; the Free tier estimates to zero. Messages beyond the per-unit included quota are usage-based and supplied in c3x-usage.yml. As with SignalR, size units to peak concurrent connections, that's the dimension that usually forces the unit count.

Terraform example

A minimal but realistic configuration that C3X can estimate.

resource "azurerm_web_pubsub" "live" {
  name                = "app-live"
  resource_group_name = azurerm_resource_group.app.name
  location            = "eastus"

  sku      = "Standard_S1"
  capacity = 2
}

Pricing dimensions

What you actually pay for when you provision azurerm_web_pubsub.

Dimension	Unit	What's being charged
Service units	per unit-day	Per-unit daily rate by tier. Each Standard unit includes 1,000 concurrent connections and 1M messages/day. c3x prices capacity x ~30.4 days/month. $1.61/unit-day (Standard), $2.00 (Premium)
Additional messages	per million messages	Messages beyond the included per-unit quota. Usage-based; define in c3x-usage.yml.

Sample C3X output

Example output from c3x estimate (Standard, 2 units):

azurerm_web_pubsub.live
└─ Service units (Standard x 2)   60.8  unit-days    $97.88

OVERALL TOTAL                                        $97.88

Optimization tips

Common ways to reduce azurerm_web_pubsub cost without changing the workload.

Size units to peak concurrent connections

Per excess unit

Each Standard unit covers 1,000 concurrent connections. Provision units for real peak concurrency, not a round number; over-provisioning units is the main waste.

Use the Free tier for development

100% in non-prod

The Free tier (20 connections) costs nothing and suits development and small demos. Reserve paid units for production traffic.

Choose Standard unless you need AZ redundancy

~20%

Premium adds zone redundancy and autoscaling at ~25% more per unit. For most apps Standard delivers the same messaging at the lower rate.

FAQ

How does c3x estimate Azure Web PubSub cost?

It reads the sku tier and capacity and prices unit-days at ~30.4 days/month. Messages beyond the per-unit included quota are usage-based. The Free tier estimates to zero.

How is this different from Azure SignalR?

Both are managed real-time messaging priced per unit-day. SignalR is optimized for the SignalR protocol and .NET; Web PubSub is protocol-agnostic over raw WebSockets for any client. The pricing model is the same.