Email Authentication Checklist for E-commerce

List order confirmations, receipts, shipping updates, vendor POs, RMAs, and support replies, then map which systems send or receive them so your inbound API and webhook routing matches real traffic.

Use subdomains like orders.example.com for transactions and promos.example.com for marketing, reducing risk to DMARC alignment on high-value order flows processed by your parsing pipeline.

Create returns@, vendors@, invoices@, and disputes@ and decide whether each will be consumed via inbound email API, webhook, or polling, with pre-parse SPF/DKIM/DMARC checks at the edge.

Record ESPs, helpdesks, ERPs, WMS, marketplace proxy addresses, and shipping platforms, noting SPF includes and DKIM selectors to keep webhook-delivered authentication verdicts consistent.

Commit to faster p=reject for order confirmations and slower for marketing, aligning with fraud risk and downstream automation that consumes parsed MIME and webhook events.

Ensure your team can update SPF, DKIM, and DMARC quickly, lower TTLs during rollout, and coordinate with release cycles that impact inbound parsing and API consumers.

Authorize only your ESP, helpdesk, ERP, and ticketing sources, keep under 10 DNS lookups, and use subdomain-specific SPF so authentication results in webhook payloads are predictable.

Create unique selectors for ESP, helpdesk, and ERP senders, rotate keys regularly, and document selectors so your parsing and verification step can validate d= signatures reliably.

Ensure the From domain matches the DKIM signing domain and envelope sender, preserving alignment so DMARC passes and your automated pipelines trust inbound messages.

Publish v=DMARC1; p=none; rua=mailto:reports@yourdomain; fo=1; aspf=s; adkim=s to gather data, then feed results into monitoring used by your inbound API and webhook processors.

Use strict sp=reject for transactional subdomains and more lenient policies for marketing, keeping fraud out of message streams your parsers and webhooks act on.

Point MX for vendors@ and returns@ to your intake service and use unique aliases or plus tags per vendor for traceability through MIME parsing and webhook events.

Turn on domain-signed DKIM and disable shared domains so transactional messages land with aligned auth that downstream APIs can trust for order automation.

Use DKIM-capable SMTP relays or your ESP to sign invoices and POs, ensuring messages parsed by your inbound API pass DMARC.

Apply Sender Rewriting Scheme on addresses like support@ that forward into ticketing so SPF survives and DMARC verdicts sent via webhooks remain correct.

Verify SPF, DKIM, and DMARC at intake, then accept, quarantine, or reject before MIME parsing to block fraudulent RMAs and supplier invoice scams.

Expose spf_pass, dkim_pass, dmarc_result, and aligned flags so fulfillment, accounting, and returns workflows can gate automation based on trust.

Extract relevant parts from multipart messages, parse attachments, and retain Authentication-Results and ARC headers in your stored JSON for auditability.

Send sample order confirmations, shipping notices, RMAs, and vendor POs to major inbox providers and confirm Authentication-Results and alignment in your webhook logs.

Flatten or prune excessive includes and split subdomain records so inbound API verdicts never fail due to permerror in peak sale events.

Use captured EML samples to validate MIME parsing, attachment extraction, and that API responses carry accurate SPF, DKIM, and DMARC outcomes.

Validate that proxy addresses and forwarding preserve DMARC via ARC or SRS, preventing false fails that would block webhook-driven automations.

Temporarily disable a DKIM selector or tighten DMARC on a staging domain to verify quarantine workflows and human review of high-risk return requests.

Introduce a new selector, sign with both old and new until pass rates stabilize in inbound logs, then retire the old key without disrupting parsing pipelines.

Ingest rua data into dashboards by storefront and vendor, track pass rates and aligned sources, and promote transactional streams to p=quarantine then p=reject.

Create alerts for SPF permerror, DKIM fail spikes, or DMARC reject surges that could impact order confirmations or returns processed via webhooks.

Quarterly rotation with documented selectors and rollback plans reduces key exposure while keeping signature verification stable for your inbound API.

Route high-risk messages to manual review when SPF and DKIM both fail, and block webhook-triggered refunds until trust is established.

Gate supplier onboarding so invoices and shipping notices must pass SPF or DKIM before entering parsing and AP or WMS workflows.

Allow limited exceptions for critical vendors and addresses, with expiration and logging, so shipments are not delayed while SPF or DKIM is fixed.