Infrastructure cost reports¶


ID	`MOD-099`
System	SD07
Repo	`bank-platform`
Build status	Deployed
Deployed	Yes
Last commit	`bbdfbac46a1b5cf6dc25b4c7cd428a8daa669d03`

Billing schema ownership¶

MOD-099 owns the billing.* Snowflake schema. This is an explicit ownership transfer — MOD-098 provisioned BILLING.TENANT_MODULES and BILLING.TENANT_TIERS as stubs to unblock its own dbt models, pending MOD-099 shipping.

When MOD-099 is built, the agent must:

Provision BILLING.TENANT_MODULES and BILLING.TENANT_TIERS in MOD-099-usage-billing-report/infra/snowflake/ with the canonical schema (see MOD-098 design doc for the current stub definitions — MOD-099 should adopt these column shapes and extend them as needed).
Add BILLING.INVOICES and BILLING.INVOICE_LINE_ITEMS tables to the same infra/snowflake/ directory.
Remove billing.sql and billing_*.sql from MOD-098-cost-attribution-engine/infra/snowflake/ in a co-ordinated deployment — MOD-099 must be deployed first so the tables exist before MOD-098's DDL files are removed. Use CREATE TABLE IF NOT EXISTS in MOD-099's scripts so a re-run against an already-populated schema is safe.
Update dbt/models/MOD-098-cost-attribution-engine/sources.yml to reference the billing.* tables as an external source owned by MOD-099 rather than as a source owned by MOD-098 itself.

Deployment order constraint: MOD-099 DDL must be applied before MOD-098's stub DDL is removed. The CI/CD workflow for the MOD-098 cleanup commit must depend on a successful MOD-099 deploy.

Purpose¶

MOD-099 surfaces the cost attribution data computed by MOD-098 as a transparent, usable report for two audiences: the licensee (who needs to understand what they are paying for and why) and internal finance (who need to understand unit economics, gross margin, and platform cost trends).

The transparency principle is a deliberate commercial decision. Licensees who can see their usage breakdown in real time are less likely to dispute invoices, more likely to trust the platform, and better positioned to forecast their own costs.

Licensee-facing dashboard¶

Available in the back-office portal under Billing & Usage. Accessible to any user with the BILLING_VIEWER or BILLING_ADMIN access grant on their tenant context.

Current period summary card¶

Billing period: 1 Apr – 30 Apr 2026
Customer levy:       $4,200.00   (1,400 active customers × $3.00)
Facility fees:       $2,750.00   (11 modules × $250.00/month)
Variable usage:      $  830.40   (see breakdown)
Infrastructure:      $  412.00   (passthrough — see detail)
─────────────────────────────────
Estimated total:     $8,192.40
(Final invoice issued 3 May 2026)

Variable usage drill-down¶

Resource type	Included	Used	Overage	Rate	Charge
Snowflake credits	500	823	323	$0.50/credit	$161.50
ML inferences	50,000	94,200	44,200	$0.003/call	$132.60
Enrichment API calls	100,000	187,400	87,400	$0.002/call	$174.80
Notification sends	20,000	51,300	31,300	$0.008/send	$250.40
Document storage	10 GB	13.9 GB	3.9 GB	$28.80/GB/mo	$111.10

Module-level breakdown¶

Module	Facility fee	ML inferences	Enrichment calls	Snowflake credits	Total
MOD-009 eIDV	$250	—	12,400 calls	18 credits	$274.80
MOD-039 Risk scoring	$250	94,200 inferences	—	380 credits	$564.90
MOD-041 Categorisation	$250	—	175,000 calls	425 credits	$963.50
…	…	…	…	…	…

Infrastructure passthrough (optional toggle)¶

AWS service	Cost
Lambda	$84.20
API Gateway	$63.40
Kinesis Firehose	$41.10
S3	$28.90
DynamoDB	$19.80
EventBridge + SQS	$12.30
Secrets Manager	$8.20
Snowflake (dedicated warehouse)	$154.10
Total passthrough	$412.00

Trend chart¶

30-day rolling chart showing daily estimated cost, with annotations for significant events ("New module activated", "Customer count crossed 1,000").

Export¶

Download current period breakdown as CSV or PDF
API endpoint: GET /billing/usage?period=2026-04&format=json (authenticated, tenant-scoped)

Internal finance view¶

Accessible to Finance and Platform teams in the back-office portal.

Gross margin by tenant¶

Tenant	Revenue	AWS cost	Snowflake cost	External APIs	Total cost	Gross margin
Tenant A	$8,192	$264	$154	$112	$530	93.5%
Tenant B	$3,450	$118	$67	$44	$229	93.4%
…

Unit economics¶

Module	Cost per customer per month	At 1,000 customers	At 10,000 customers
MOD-009 eIDV	$0.12	$120	$890 (scale discount)
MOD-039 Risk score	$0.38	$380	$2,800
MOD-041 Categorisation	$0.69	$690	$4,100

Unattributed cost monitor¶

Any AWS costs with no tenant_id tag appear here. A non-zero unattributed bucket is a tagging governance gap and triggers an engineering alert.

Invoice generation¶

At the end of each billing period, MOD-099 generates: - One billing.invoices record per tenant with the period total - One billing.invoice_line_items record per billing component (customer levy, each facility fee, each variable line, passthrough) - Invoice status flows: DRAFT → ISSUED → PAID / DISPUTED - PDF invoice generated and stored in S3 (ADR-028); URL written to the invoice record - bank-platform.invoice_issued EventBridge event triggers notification to the licensee's billing contact

Module dependencies¶

Depends on¶

Module	Title	Required?	Contract	Reason
MOD-098	Cost attribution engine	Required	—	Reporting views and Dynamic Tables read from MOD-098's metering schema (aws_cost_daily, snowflake_credit_daily, daily_tenant_summary, billing_period_summary, unit_economics) in BANK_{ENV}_RISK.
MOD-102	Snowflake account configuration & governance	Required	—	Snowflake account and BANK_{ENV}PLATFORM database provisioned by MOD-102 must exist before this module can create the REPORTS schema and objects; cross-database SELECT grant on BANK_RISK.METERING also applied by MOD-102 setup.

Required by¶

(No modules in this wiki currently declare a dependency on this module.)

Policies satisfied¶

Policy	Title	Mode	How
REP-001	Regulatory Reporting Policy	`LOG`	Infrastructure cost history is retained as queryable Snowflake records — provides audit trail for AWS and Snowflake spend by service, period, and attributed tenant.

Capabilities satisfied¶

Capability	Title	Mode	How
CAP-140	CAP-140	`CALC`	Provides Snowflake views and Dynamic Tables in BANK_{ENV}PLATFORM.REPORTS aggregating MOD-098's metering data; surfaces daily AWS and Snowflake costs by service, environment, and tenant — directly queryable from Snowsight and Streamlit without access to the BANK_RISK database.

Part of SD07 — Data Platform & Governance Infrastructure Compiled 2026-05-22 from source/entities/modules/MOD-099.yaml