Cost estimate

The Cost tab estimates monthly cost from the public Azure Retail Prices API (pay-as-you-go list prices, USD). It is deterministic code, never a model's arithmetic, and every number can be traced to a rate, a quantity and an assumption.

What the tab shows

• Totals per month and per year, how many components were priced, and how many were not.
• By category (compute, data and storage, AI and agents, …) and by component, with every line item expanded as quantity × rate = cost and the meter id.
• Assumptions — every input is tagged from spec (you stated it) or assumed (a default). Any defaulted input makes the estimate indicative.
• Sensitivity at 1×, 3× and 10× traffic, and what-ifs (Functions Flex Consumption, SQL zone redundancy, Azure OpenAI batch deployments, Blob Cool tier) where they apply.
• Provenance: the effective date of each price list and the retrieval date.
• A checkbox that overlays $/mo on the diagram.

Giving it real numbers

Put a usage object on each node. Anything you leave out falls back to a documented default and is flagged as assumed.

{ "id": "fm", "icon": "openai", "label": "Azure OpenAI",
  "usage": { "model": "gpt-4o-0806", "inputTokensPerMonth": 150000000, "outputTokensPerMonth": 15000000 } }

Describe the scenario once in meta.cost.note so readers know the basis:

"meta": { "title": "…", "cost": { "region": "eastus", "note": "Illustrative: 200,000 questions/month, ~750 input and 75 output tokens each" } }

Usage keys by service

Service	Keys (default)
Azure Functions	plan (consumption, flex, premium), requestsPerMonth (1e6), avgDurationMs (200), memoryMb (512); premium: instances (1), vcpu (1), memoryGb (3.5)
Azure App Service	sku (P1v3), os (linux/windows), instances (2)
Azure Virtual Machines	vmSize (Standard_D2s_v5), count (2), hoursPerMonth (730)
Azure Storage (Blob)	accessTier (hot, cool…), redundancy (LRS…), storageGb (100), writeOperationsPerMonth (1e5), readOperationsPerMonth (1e6)
Azure Cosmos DB	mode (provisioned or serverless), ruPerSecond (1000), storageGb (50), regions (1)
Azure SQL Database	tier (general-purpose or business-critical), vcores (2), zoneRedundant (false), storageGb (100)
Azure Service Bus	tier (standard, premium), messagingUnits (1), operationsPerMonth (5e6)
Azure Event Hubs	tier (standard), throughputUnits (1), ingressEventsPerMonth (1e7)
Azure API Management	tier (standard, consumption…), callsPerMonth (1e6), units (1)
Azure Application Gateway	waf (true), avgCapacityUnits (3)
Azure Front Door	tier (standard/premium), egressGbPerMonth (100), requestsPerMonth (1e7)
Azure Key Vault	operationsPerMonth (1e5)
Azure Monitor Log Analytics	ingestGbPerMonth (10), retentionDays (31), retainedGb (10)
Azure AI Search	sku (standard-s1), searchUnits (3)
Azure OpenAI / Foundry models	model is required (for example gpt-4o-0806, gpt-5-mini, text-embedding-3-small), deployment (global, regional, datazone), mode (standard or batch), inputTokensPerMonth (5e6), outputTokensPerMonth (1e6), cachedInputTokensPerMonth (0)
Azure Document Intelligence	feature (read…), pagesPerMonth (10000)
Azure AI Content Safety	textRecordsPerMonth (1e5), imagesPerMonth (0)
Azure Cache for Redis	tier (standard), size (C1), instances (1)
Azure Kubernetes Service	tier (free/standard/premium), nodeVmSize (Standard_D4s_v5), nodeCount (3)
Azure Container Registry	sku (standard)
Azure Firewall	sku (standard), dataProcessedGbPerMonth (100)
Azure Bastion	sku (basic)
Azure Event Grid	operationsPerMonth (5e6)
Azure Load Balancer	rules (5)
Azure Public IP	count (1)

Model names are matched exactly or as a unique prefix; an ambiguous name is an error that lists the candidates, never a guess.

Two keys work on any node:

• usage.monthlyUsd — supply the monthly cost yourself (status override). Use it for services without a cost model, and say where the number came from.
• usage.egressGbPerMonth — adds internet data-transfer-out.

Honest statuses

Status	Meaning
estimated	Priced from the price list with the stated and assumed inputs.
override	You supplied usage.monthlyUsd.
no-charge	The service has no direct charge (virtual networks, NSGs, managed identities, Azure Policy…).
not-billable	A general icon (users, internet), not an Azure resource.
not-itemized	the price list has no separate meter for it.
needs-input	A required input is missing (for example the Azure OpenAI model).
not-estimated	No cost model for this service yet. Supply usage.monthlyUsd to include it.
error	The price book could not resolve an unambiguous rate; the reason is shown.

The total only includes priced components, and the tab says how many were left out.

What is and is not included

Included: public pay-as-you-go rates; 730 hours per month; free grants that the API lists as zero-price tiers (for example Functions' monthly free executions). Excluded: taxes, support plans, Reservations, Savings Plans, Spot, Azure Hybrid Benefit, enterprise agreements and credits, and data transfer unless you set egressGbPerMonth. Treat the result as a planning number and confirm it in the Azure Pricing Calculator.

From the command line

archify-azure cost spec.json                       # table in the terminal
archify-azure cost spec.json --scale 1,3,10        # sensitivity points
archify-azure cost spec.json --region eastus      # needs data/prices/<region>.json
archify-azure cost spec.json --usage usage.json    # {"<nodeId>": {…usage keys…}} overrides the spec's usage
archify-azure cost spec.json --json                # full machine-readable result

Turn the tab off with render --no-cost / finalize --no-cost.

The price snapshot is committed (data/prices/eastus.json, 28 price lists). Developers refresh it with npm run prices:fetch; see Data refresh.