Launch Ready cyber security Checklist for AI-built SaaS app: Ready for customer onboarding in marketplace products?.

What "ready" means for an AI-built SaaS app selling into marketplace products

For this kind of product, "ready" does not mean "the app runs on my laptop." It means a customer can sign up, verify email, enter the product through a marketplace flow, and complete onboarding without exposing data, breaking auth, or triggering support.

I would call it ready only if these are true:

• The app is deployed on production infrastructure with SSL on every public endpoint.
• DNS, redirects, and subdomains are correct, including auth callback URLs.
• Email deliverability is working with SPF, DKIM, and DMARC passing.
• No secrets are exposed in code, logs, build output, or client-side bundles.
• Marketplace onboarding flows do not break on mobile, slow networks, or edge cases.
• Uptime monitoring is active and alerting the right person.
• There are no critical auth bypasses, open admin routes, or public write endpoints.
• Core pages load fast enough to support conversion: LCP under 2.5s on mobile is the target I use for launch readiness.

If any one of those fails, you do not have a launch-ready customer onboarding path. You have a demo that can lose customers, leak data, or get rejected by a marketplace review team.

This checklist is for founders shipping an AI-built SaaS app into marketplace products and wanting the security and deployment basics handled fast.

Quick Scorecard

| Check | Pass criteria | Why it matters | What breaks if it fails | |---|---|---|---| | HTTPS everywhere | All public URLs redirect to HTTPS with valid certs | Protects login and onboarding traffic | Browser warnings, failed auth callbacks | | DNS correct | Root, www, app, api, and auth subdomains resolve correctly | Marketplace flows depend on exact hostnames | Broken redirects and sign-in loops | | Email authentication | SPF, DKIM, DMARC all pass | Stops inbox spam placement and spoofing | Onboarding emails land in spam | | Secrets protected | Zero exposed API keys or private tokens | Prevents account takeover and billing abuse | Data leaks and unexpected spend | | Auth locked down | No critical auth bypasses or public admin routes | Protects customer accounts and tenant data | Full compromise of user records | | CORS and callbacks set | Only approved origins and redirect URIs allowed | Prevents token theft and cross-site abuse | OAuth failures or token leakage | | Rate limiting active | Login and signup endpoints throttled | Reduces brute force and bot abuse | Credential stuffing and support load | | Monitoring enabled | Uptime checks plus alerts for errors and downtime | Detects outages before customers do | Silent failures during onboarding | | Deployment verified | Production build matches expected env vars and routes | Stops broken release surprises | Blank pages or failed checkout/signup | | Handover complete | Runbook covers rollback, access list, alerts, owners | Keeps ops from collapsing after launch | Slow incident response |

The Checks I Would Run First

1. Public attack surface check

Signal: I want to know exactly what the internet can reach. If I find admin panels, debug routes, staging hosts, or old subdomains exposed publicly, that is a launch blocker.

Tool or method: I would inspect DNS records, crawl public routes, check robots.txt only as a hint not a defense layer, review Cloudflare zones if present, and scan for common leaked paths like /admin, /api/debug, /healthz, /swagger.json.

Fix path: Remove unused hosts from DNS. Put admin tools behind authentication plus IP allowlists where possible. Disable debug endpoints in production. If staging must exist, isolate it with separate auth and no production data.

2. Secret exposure check

Signal: I look for API keys in source control history, frontend bundles, environment dumps in logs, Vercel or Netlify previews, CI output files, and error reports. One exposed secret is enough to fail this check.

Tool or method: Search the repo history with secret scanners such as git-secrets or trufflehog. Inspect browser source maps if they are published. Review logs for tokens accidentally printed by the AI-generated code.

Fix path: Rotate every exposed key immediately. Move secrets to server-side environment variables only. Strip secrets from client code. Add pre-commit scanning so the same mistake cannot ship again.

3. Authentication flow check

Signal: I test signup login logout password reset magic links OAuth callbacks session expiry invite links and tenant switching if the app is multi-tenant. A marketplace onboarding flow often fails at the callback stage because one URL is wrong.

Tool or method: Walk the full journey in an incognito browser on desktop and mobile widths. Test slow network conditions too. Verify callback URLs exactly match provider settings such as Google Clerk Auth0 Supabase or custom OAuth.

Fix path: Lock redirect URIs to an allowlist. Set secure HttpOnly cookies where possible. Make session expiration predictable. Add clear error states when tokens expire instead of dumping users onto blank screens.

4. Email deliverability check

Signal: Onboarding emails must arrive in inboxes not spam folders. If SPF DKIM or DMARC fail then password resets invites receipts verification emails can get delayed or blocked entirely.

Tool or method: Check DNS records against your mail provider's requirements using tools like MXToolbox or your provider's own validator. Send real test emails to Gmail Outlook and iCloud accounts.

Fix path: Publish SPF DKIM DMARC records correctly at DNS level. Use one verified sending domain only. Set a DMARC policy that starts at p=none during validation then tighten later after monitoring results.

Here is the minimum pattern I expect:

v=spf1 include:_spf.yourmailprovider.com -all

That line alone is not enough by itself. It must match your actual mail provider setup and be paired with DKIM signing plus DMARC policy.

5. CORS CSRF and callback trust check

Signal: If your frontend can call any backend origin freely you may have created a data exposure path. If state changing requests do not require CSRF protection then session-based apps become easier to abuse.

Tool or method: Review CORS headers in production responses. Test whether unauthorized origins can read API responses. Confirm POST PUT PATCH DELETE routes require proper auth plus anti-CSRF controls when cookies are used.

Fix path: Allow only known origins such as your app domain and marketplace domains you actually need. Never use wildcard CORS with credentials enabled. For cookie sessions add CSRF tokens or same-site protections based on architecture.

6. Production observability check

Signal: I need evidence that you will know about outages before customers complain in Slack or leave bad reviews inside the marketplace product ecosystem.

Tool or method: Verify uptime monitoring hits login landing page checkout webhook health endpoint if needed plus critical APIs every minute from more than one region. Confirm error logging captures stack traces without leaking secrets.

Fix path: Add uptime alerts to email Slack SMS or PagerDuty depending on severity budget. Track p95 latency for onboarding APIs with a target under 500ms where practical for core reads. Log request IDs so support can trace failed sessions quickly.

Red Flags That Need a Senior Engineer

1. The app has working auth but no clear tenant isolation.

• That means one bug could expose another customer's workspace data.

2. The build depends on environment variables nobody can explain.

• That usually means hidden coupling between frontend backend email providers payments and deployment settings.

3. The marketplace callback flow was "fixed" by trial and error.

• That often breaks again after the next deploy because nobody documented the contract.

4. Secrets were pasted into frontend code during testing.

• This is how AI-built apps accidentally ship private keys into public bundles.

5. The founder cannot describe rollback if deployment fails.

• If there is no rollback plan then every release becomes a business risk window.

DIY Fixes You Can Do Today

1. Rotate any key you even suspect might be exposed.

• Do this before anything else if you used AI-generated code across multiple tools.

2. Turn on Cloudflare proxying for public web traffic.

• Enable SSL mode correctly force HTTPS set basic WAF rules where appropriate and block obvious bot noise early.

3. Audit your DNS records line by line.

• Check root domain www app api mail sender subdomains auth callbacks MX TXT CNAME records against actual providers.

4. Send test emails from three inbox providers.

• Use Gmail Outlook and Apple Mail to confirm inbox placement link rendering unsubscribe behavior and sender identity consistency.

5. Open your app on mobile over slow 4G simulation.

• If onboarding breaks when images load late buttons shift or forms reset then customers will drop off fast.

Where Cyprian Takes Over

If your checklist shows gaps across deployment security email delivery DNS SSL secrets monitoring or handover then Launch Ready is the fastest fix path I would recommend over piecemeal DIY work.

| Failure found | Deliverable | |---|---| | Wrong DNS or broken redirects | DNS cleanup root www app api subdomain mapping redirect rules | | Missing SSL or mixed content issues | HTTPS enforcement certificate validation Cloudflare setup | | Weak protection at edge layer | Cloudflare configuration caching DDoS protection basic WAF hardening | | Bad sender reputation setup | SPF DKIM DMARC records validated against real mail provider | | Exposed secrets risk | Environment variable audit secret removal rotation guidance | | Unmonitored production release | Uptime monitoring alert setup owner routing runbook notes | | Broken deployment process | Production deployment verification plus handover checklist |

My timeline is simple:

• Hour 0 to 8: audit current state identify blockers verify domains email providers hosting access.
• Hour 8 to 24: fix DNS SSL redirects Cloudflare edge config secrets handling mail authentication.
• Hour 24 to 36: validate production deployment confirm onboarding journey test key paths across devices.
• Hour 36 to 48: add monitoring finalize handover document rollback notes access list next steps.

If you want customer onboarding ready for marketplace products without dragging this out for weeks I would take this route instead of ad hoc fixes that create more cleanup later than they save now.

Delivery Map

References

• roadmap.sh code review best practices: https://roadmap.sh/code-review-best-practices
• roadmap.sh API security best practices: https://roadmap.sh/api-security-best-practices
• roadmap.sh cyber security: https://roadmap.sh/cyber-security
• OWASP Top Ten: https://owasp.org/www-project-top-ten/
• Cloudflare SSL/TLS documentation: https://developers.cloudflare.com/ssl/

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Take the next step

If this is a problem in your product right now, here is what to do next:

• [Use the free Cyprian tools](/tools) - estimate cost, score app risk, check launch readiness, or pick the right service sprint.

• [Book a discovery call](/contact) - I will tell you honestly whether you need a sprint or if you can DIY the next step.

*Written by Cyprian Tinashe Aarons - senior full-stack and AI engineer helping founders rescue, launch, automate, and scale AI-built products.*