Payments Dashboard

AWS SAM application that ingests payment CSVs, syncs check data with Bank of America CashPro APIs, processes Gusto payroll confirmation emails into Slack notifications, surfaces an outstanding-payments dashboard in Slack, and routes expense approvals through a Slack reaction-driven workflow.

Architecture

• ProcessPayrollEmail — Lambda triggered by S3 (inbound email) and SQS (batch timer). SES receives Gusto payroll emails at payroll@int.seahaven.com, stores them to S3, and this Lambda parses the email body, extracts financial data, and posts a combined Slack notification (employee payroll + contractor payments) after a 10-minute batching window. Runs outside VPC.

• ProcessPaymentCsv — Lambda triggered by S3 CSV upload. Parses Stampli payment exports, upserts to DynamoDB, and submits new/cancelled checks to the CashPro Check Management API.

• FetchBoaTransactions — Scheduled Lambda (weekdays 9am ET). Calls the CashPro Previous Day Transaction Inquiry API, classifies each transaction (paid checks, ARP refer-to-maker and return-of-posted-check credits, electronic returns), and reconciles them onto DynamoDB payment records. See Bank reconciliation.

• SlackAppHome — Lambda behind API Gateway (POST /slack/events). Verifies the Slack signing secret (HMAC-SHA256, 5-minute replay window) before processing, then renders the payments dashboard on the Slack App Home tab with outstanding aging buckets and drill-down modals.

• ExpenseReceiver — Lambda behind API Gateway (POST /slack/expense-events). Verifies the Slack signing secret (HMAC-SHA256), handles URL verification challenges, and async-invokes ExpenseProcessor. Runs outside VPC.

• ExpenseProcessor — Async Lambda invoked by ExpenseReceiver. Processes :white_check_mark: reactions to advance expense messages through a four-stage Slack channel pipeline: Submitted → Processed → Authorized → Matched. Runs outside VPC.

ProcessPaymentCsv, FetchBoaTransactions, and SlackAppHome run inside a VPC with a NAT Gateway for a static outbound IP (required by BoA IP whitelisting). ProcessPayrollEmail, ExpenseReceiver, and ExpenseProcessor run outside the VPC.

Expense Approval Bot

Reaction-driven workflow that routes expense submissions through four Slack channels. A separate Slack app ("Expense Approval Bot") posts to a Submitted channel. Users react with ✅ to advance the message to the next stage.

Channel pipeline:

Stage	Channel ID	Action on ✅
Submitted	C0AQ2AWLNEN	Thread reply on original, copy to Processed
Processed	C0APLSGABAB	Delete from Processed, post to Authorized
Authorized	C0AQ09CDJH4	Delete from Authorized, post to Matched
Matched	C0APYUM1JFP	Terminal stage (no further routing)

Architecture: Two Lambdas — ExpenseReceiver (HTTP endpoint, signature verification, async invoke) and ExpenseProcessor (business logic). This is the same receiver/processor pattern used for Slack's 3-second timeout requirement.

Secrets (Secrets Manager):

Secret	Purpose
payments-dashboard/expense-slack-token	Slack Bot token for the Expense Approval Bot app
payments-dashboard/expense-slack-signing-secret	Slack signing secret for request verification

Payroll Email Pipeline

Gusto sends payroll confirmation emails when payroll is run. A Gmail filter on adam@seahavenind.com auto-forwards emails from automated@gusto.com and gustonoreply@gusto.com to payroll@int.seahaven.com.

Flow: Gmail forward → SES receipt rule → S3 bucket → Lambda parses email → DynamoDB (pending) → SQS delay queue (10 min) → Lambda batches all pending items for that date → single Slack message → DynamoDB (notified)

Deduplication: Each email is deduplicated by DynamoDB key (PAYROLL_EMAIL#employee#<date> or PAYROLL_EMAIL#contractor#<date>#<bank-suffix>). The batch post is deduplicated by PAYROLL_BATCH#<date>. All items have a 90-day TTL.

BoA CashPro API Integration

Two separate CashPro APIs are used, each with its own OAuth credentials:

API	Purpose	Endpoint
Check Management	Issue and cancel checks	/cashpro/checkmanagement/v1/check-issues
Reporting (Transaction Inquiry)	Fetch previous-day transactions	/cashpro/reporting/v1/transaction-inquiries/previous-day

Authentication flow:

1. POST to /authn/v1/client-authentication with applicationID, client_id, and client_secret
2. Receive a Bearer access_token (valid 1 hour)
3. Pass the token in the Authorization header for subsequent API calls

Base URLs:

• Production: https://api.bofa.com
• Sandbox: https://api-sb.bofa.com

Bank reconciliation (fetchBoaTransactions)

The scheduled Lambda reconciles the Previous Day feed onto payment# records (pure logic lives in src/boaRecon.js, covered by npm test).

Classification. Transactions are classified via a BAI transaction-code map (BAI_CODE_EVENTS; only 475 = check paid debit is empirically confirmed so far — the remaining codes are pending an enumeration replay over known event dates) with a fallback classifier over the statement description formats (ARP refer-to-maker, return-of-posted-check check-numbered and electronic variants, ACH CCD DES:PAYMENTS ID:PMT lines). Unmapped codes on check-shaped transactions are logged (console.error) and counted in the run summary — never silently dropped.

Matching. Check events match on check number AND amount, evaluating all candidates (bank postings can drop/collapse digits on long check numbers). A number match with the WRONG amount never auto-resolves — it is the altered-check/collapsed-posting signal and goes to unmatched for human review. An unknown number falls back to an exact-amount match within checks issued in the last 120 days, and only when the posting's digits are a subsequence of the candidate's check number (or vice versa); return credits additionally require a bank-confirmed candidate. Zero or multiple fallback candidates means unmatched, recorded in the run summary with no write. Electronic returns (no check number) match by exact amount among bank-confirmed payments.

ACH. ACH is bank-confirmed too (#69): processPaymentCsv no longer auto-clears ACH on the send date (rows keep their Stampli status until the bank settles). ACH CCD lines match by the stored pmt_id first (reversals reuse the original PMT <id>; a pmt_id match with the wrong amount is the partial-reversal human case and goes to unmatched), then by the Stampli payment number embedded at the end of PMT INFO (internal spaces stripped, amount must agree), then by vendor + exact amount within send_payment_on −2..+14 days (candidates whose stored pmt_id differs are excluded; vendor prefix matching requires ≥ 10 normalized chars). A settled debit clears the record and persists pmt_id. A return credit whose PMT <id> attributes to no stored pmt_id is an unmatched alert ("unknown PMT id"); credits without a PMT <id> may fall back to a unique same-amount match against a bank-confirmed ACH whose cleared_date is within the prior 45 days.

Staleness sweep. Every run also flags never-bank-confirmed payments: ACH with no clear_status sent more than 16 days ago (listed in the summary, capped at 50, plus a total count) and checks issued more than 60 days ago with no clear_status (count only). Both alert via console.error.

State transitions. Every write sets BOTH status and clear_status (clear_status is bank truth; "Cleared without a subsequent return is permanent" keys off it):

Bank event	Result
Paid debit	status=Cleared, clear_status=Cleared, paid_date, cleared_date, bank_reference
Return credit (even if currently Cleared)	clear_status=Returned, returned_date; status re-written unchanged (the CSV ladder has no Returned rung)
Second paid debit on a Returned check	Redeposit: back to Cleared with new dates
Return on a Stampli-voided check	Terminal voided-and-bounced (clear_status=Returned, cancel status preserved), counted separately

Each applied event is appended to a history list attribute ({event, date, bankRef, amount}); identical replayed events are idempotent noops.

Replay. The handler accepts an optional payload {"fromDate": "YYYY-MM-DD", "toDate": "YYYY-MM-DD"} (strictly validated; toDate defaults to fromDate) for weekend/outage gap replays and BAI-code enumeration runs. With no payload it queries the trailing 3-day window (today−3 .. today−1), so the Monday run covers Friday–Sunday; overlapping days are idempotent (event identity {event, date, amount}). Feed rows without a valid valueDate are never applied with a substituted date — they go to unmatched for review.

Run summary. Each run writes an append-only boa_recon#<fromDate>_<toDate>#<runAt> item (90-day TTL) with counts per classified event type, matched/applied/redeposit/voided-and-bounced/write-conflict totals, the unmatched check numbers and amounts (list capped at 50; full count kept), unknown BAI codes (capped at 20 distinct keys), and the staleness sweep results. Unmatched and unknown-code transactions also console.error (Slack alerting is tracked in #71). Payment writes are conditioned on the read snapshot's status/clear_status and retried once against a fresh read on conflict.

Documentation

The canonical map of Sea Haven's AWS infrastructure lives in Confluence. This project's payments-dashboard stack is represented there as a Mermaid subgraph.

• AWS Architecture Map (Confluence, IT space, page 1540098)

Secrets

All BoA and Slack credentials are stored in AWS Secrets Manager (per engineering-handbook/secrets-and-config.md). The Slack token is a plaintext secret; the two BoA secrets are JSON grouping each API's credentials:

Secret	Type	Contents
payments-dashboard/slack-bot-token	plaintext	Slack Bot OAuth token (used by processPayrollEmail, slackAppHome)
payments-dashboard/slack-signing-secret	plaintext	Slack signing secret for slackAppHome request verification
payments-dashboard/boa-check-mgmt	JSON	appId, clientId, token, accountNumber, companyId — Check Management API (processPaymentCsv)
payments-dashboard/boa-reporting	JSON	appId, clientId, token, accountNumber, bankId — Reporting API (fetchBoaTransactions)

boa-account-number is duplicated into both BoA secrets. Each Lambda is granted secretsmanager:GetSecretValue scoped to only the secret it needs. The Expense Approval Bot uses two additional secrets (payments-dashboard/expense-slack-token, payments-dashboard/expense-slack-signing-secret).

Consumers / data contract

The PaymentsDashboard DynamoDB table (AWS::DynamoDB::Table, TableName: PaymentsDashboard, PK pk (S), CMK-encrypted) is owned by this stack, which is the sole authoritative writer.

Consumer (read-only): seahaven-slack-bot imports this table via Table.fromTableName(...) and reads it read-only (grantReadData plus an explicit kms:Decrypt grant on the shared CMK) from its wo-po-lookup Lambda, which backs the Bedrock agent's payment-lookup action group. The bot depends on:

• Key schema: PK pk (S) with the item format payment#<check_number>. It does GetItem by pk and a full-table Scan filtered begins_with(pk, "payment#").
• Attributes: check_number, payee, amount_usd, method, status, send_payment_on, clear_status, cleared_date, invoice_numbers, company_subsidiary, bank_reference.
• Encryption: the shared customer-managed CMK (/seahaven/dynamodb/cmk-arn). Because the consumer imports the table by name, grantReadData does not carry KMS access; a change of CMK requires re-granting on the consumer side or every read fails with kms:Decrypt AccessDenied (INFRA-95 / M-3 precedent).

The table is imported by name, so there is no compile-time link between the stacks: any change to the table name, pk format, these attribute names, the encryption key, or the table's lifecycle policy will silently break the Bedrock agent at runtime. Coordinate such changes with seahaven-slack-bot before shipping (INFRA-138).

Monitoring & Alarms

All CloudWatch alarms publish to the shared site-alerts SNS topic (arn:aws:sns:us-east-1:328440206208:site-alerts). Alarms are ALARM-only by convention (no OK/recovery action) and treat missing data as notBreaching. Each alarm evaluates a single 5-minute period.

SQS dead-letter queues (messages-present, Maximum > 0):

Alarm	Source
payments-payroll-batch-dlq-messages	payments-payroll-batch-dlq
payments-processPaymentCsv-async-dlq-messages	async-invoke OnFailure DLQ
payments-processPayrollEmail-async-dlq-messages	async-invoke OnFailure DLQ

Lambda (per function — payments-<fn>-...):

Type	Metric / Statistic	Threshold
-errors (all 6)	Errors / Sum	> 0
-throttles (all 6)	Throttles / Sum	> 0
-duration (all 6)	Duration / Maximum	~80% of each function's timeout

Duration thresholds (ms): processPaymentCsv 96000, processPayrollEmail 48000, fetchBoaTransactions 48000, slackAppHome 24000, expenseProcessor 12000, expenseReceiver 4000.

DynamoDB (PaymentsDashboard table, TableName dimension, Sum > 0): payments-dashboard-table-read-throttle (ReadThrottleEvents), payments-dashboard-table-write-throttle (WriteThrottleEvents). The table is PAY_PER_REQUEST; these metrics emit only when a throttle occurs. SystemErrors is intentionally not alarmed because it does not emit at the TableName-only dimension.

API Gateway (implicit HTTP API v2 ServerlessHttpApi, ApiId dimension): payments-dashboard-api-5xx (5xx Sum > 0), payments-dashboard-api-4xx (4xx Sum > 10, client-error noise floor), payments-dashboard-api-latency-p99 (Latency p99 > 3000 ms).

Scripts

Script	Purpose
scripts/test-boa-sandbox.js	One-off sandbox connectivity test for both CashPro APIs
scripts/seed-from-csv.js	Seed DynamoDB from a local CSV file
scripts/seed-bank-status.js	Seed bank clear status data into DynamoDB

Deployment

sam build
sam deploy --guided

The BOA_BASE_URL environment variable in template.yaml controls whether Lambdas hit production (https://api.bofa.com) or sandbox (https://api-sb.bofa.com). All other BoA config is read from Secrets Manager at runtime.