Email Testing Checklist for Financial Services

Define what constitutes PII and PAN in inbound emails, then set rules for redaction, tokenization, and storage to meet GLBA and PCI DSS requirements.

Identify obligations under SOX, GLBA, PCI DSS, and regional privacy laws for invoices, bank statements, and remittance advice, then link each to test requirements.

Define retention for financial email artifacts (e.g., 7-year statements) and automated deletion windows for PII-laden JSON to minimize risk.

Allow PDFs, CSV, XML, UBL, EDI X12 810, and MT940 while blocking macro-enabled Office files and password-protected archives by default.

Model spoofing, phishing, MIME smuggling, and malware risks, then define test cases for DKIM/SPF/DMARC checks and attachment scanning outcomes.

Prepare DPA terms, security questionnaires, and audit evidence expectations for any inbound email processing service that touches financial data.

Create a sandbox domain with DMARC set to quarantine or reject to validate alignment and failure behavior without affecting production mail flow.

Use plus-addressing and deterministic tags (e.g., invoice+vendorA+pdf@domain) to route messages to specific test cases and simplify result tracking.

Ensure test addresses terminate in a non-production ingress and storage path so bad samples and malformed MIME never touch live systems.

Populate fixtures with invoices, remittance advice, bank statements, and dispute notices from real vendors and banks, including multiple locales and currencies.

Validate STARTTLS and certificate pinning where possible, and test S/MIME signed emails to ensure parser preserves signature metadata in JSON.

Allow known vendor and bank domains, then inject lookalike domains and failing DKIM to confirm quarantine logic and alerting.

Ensure correct parsing of multipart/alternative and multipart/related with inline images, preserving text/plain and text/html bodies in structured fields.

Test base64, quoted-printable, and charsets like UTF-8 and ISO-8859-1 so amounts, currency symbols, and diacritics render accurately.

Record file name, content-type, content-disposition, size, hashes, and page counts where applicable to support downstream checks and deduplication.

Pull invoice number, supplier, totals, tax, currency, due date, and line items from PDF, UBL XML, and EDI X12 810, with field confidence scores.

Detect IBAN, SWIFT/BIC, ACH routing, and account numbers with checksum validation, then mask or tokenize sensitive digits before JSON output.

Extract PO numbers, invoice references, and remittance IDs to match payments to invoices and flag short pays or discounts taken.

Remove signatures, disclaimers, and marketing footers using heuristics without discarding legally relevant notices or dispute instructions.

Sign payloads using shared secrets and timestamps, verify on receipt, and refuse processing on signature mismatch or replay windows.

Combine RFC 5322 Message-ID, body hash, and attachment hashes to dedupe retries and resends across webhook and REST flows.

Use exponential backoff for webhook failures, cap retries, and route hard errors to a dead-letter queue for manual triage.

Expose paginated polling endpoints filtered by received_at, status, and sender so downstream systems stay current during webhook outages.

Define a stable envelope for headers, bodies, and attachments with schema versioning to prevent breaking changes in financial automations.

Propagate correlation IDs from ingress through parsing, delivery, and storage to support audit queries and incident forensics.

Divert spoofed, malware-flagged, or policy-violating emails to a review queue with justifications and evidence snapshots.

Validate alignment and log failures, then gate processing or quarantine messages that do not meet policy.

Use multiple AV engines and detonation sandboxes; block macros and encrypted archives unless explicitly approved by policy.

Apply irreversible hashing or vault tokens for account numbers and PAN so downstream systems never see raw sensitive data.

Enforce least privilege on API keys, rotate regularly, store in a secrets manager, and monitor for unusual access patterns.

Ship normalized logs and email JSON digests to your SIEM, enable write-once storage, and run daily reconciliation reports.

Send hourly test emails covering key formats and verify parsing, webhook delivery, latency, and accuracy alerts.

Test new releases against curated financial datasets and track field-level accuracy, recall, and precision before promotion.