Security

Platform edge

Public traffic hits Render web services with Render’s built-in edge: automatic DDoS protection (L3/L4 and platform L7), managed TLS certificates, HTTP→HTTPS, and an optional static edge cache. We do not operate a third-party CDN or WAF zone; DNS for *.eturns.app points directly at Render.

Authentication

• Every Shopify webhook is HMAC-SHA256 verified before any side effect, using constant-time compare. Mismatch returns 401.
• Customer Account API session tokens are verified before any customer action; the sub claim is the source of truth and the body customer_id is ignored in production.
• Merchant admin routes verify the App Bridge session token; a JTI revoke list rejects logged-out tokens.
• OAuth install uses an HMAC-signed state cookie with nonce binding (HttpOnly, Secure, SameSite=Lax, scoped to /auth).

Authorization & data isolation

• Row-Level Security is enforced on every shop-scoped Postgres table via FORCE ROW LEVEL SECURITY and a per-request shop_id GUC.
• The application connects via a non-privileged role (no SUPERUSER, no BYPASSRLS).
• Shop access tokens are encrypted at rest (AES-256-GCM via Supabase Vault).
• Supabase Storage uses private buckets with short-TTL signed URLs that include a random token.

AI autonomy gates

• Confidence + dollar thresholds gate every autonomous action. Default $200 — no autonomous action above that without merchant approval.
• The never-auto-block principle: no block-customer action is exposed to the AI tool catalog. Merchants decide; the AI surfaces signals.
• Every model call goes through the Vercel AI Gateway — no direct calls to xAI, OpenAI, or Google.
• No raw PII is sent to the models — case facts use sentinel IDs and structured fields.
• Per-shop AI cost cap (circuit breaker) prevents runaway spend.

Audit & idempotency

• Every AI decision writes a row to agent_decisions with model, prompt hash, context summary, tool calls, action, dollar amount, and reasoning trace. 7-year retention.
• Every webhook is deduplicated on (topic, shop_id, payload_id); duplicate Shopify retries are no-ops.
• Financial routes (approve, inspect, refund) require an Idempotency-Key header.
• Every state transition and merchant action is recorded in audit_log_entries.

Rate limiting

Two inbound layers behind Render’s edge: an Express coarse IP rate limit on /api/admin, /webhooks, and /customer, and a shop-scoped Redis-backed limiter keyed on (shop_id, action_class, plan_tier). OTP, upload, financial, and admin-write action classes fail closed when Redis is unavailable — those surfaces never degrade to unlimited.

Supply chain

• Secret scan with gitleaks on every push.
• High+ CVEs block the build via pnpm audit:ci.
• Weekly dependency audit job.
• Trivy filesystem + IaC scan.
• Dependabot version PRs.

Content Security Policy

A per-surface CSP is applied to every customer-facing route. Violations are reported to /api/csp-report, which is itself rate-limited per IP to prevent report flooding.

Reporting a vulnerability

If you believe you have discovered a security incident or vulnerability, contact contact@eturns.app. We will provide notices of security incidents as required by applicable law.