Launch Ready API security Checklist for founder landing page: Ready for app review in marketplace products?.

What "ready" means for a founder landing page that needs app review

For a marketplace product, "ready" does not mean "the page looks good in my browser." It means the landing page can survive app review, send users to the right place, protect secrets, and not create support or security incidents on day one.

I would call it ready when all of these are true:

• The domain resolves correctly on desktop and mobile.
• SSL is live with no mixed content warnings.
• Redirects are intentional and tested.
• Email authentication passes SPF, DKIM, and DMARC.
• The page loads fast enough to avoid losing reviewers and users. I want LCP under 2.5s on mobile.
• No API keys, tokens, or private endpoints are exposed in client code.
• Forms only send data through approved endpoints with rate limiting and validation.
• Cloudflare or equivalent protection is active for caching and DDoS defense.
• Monitoring is in place so you know if the page or checkout path breaks.
• The handover is documented so you can maintain it without guessing.

If any of those are missing, you do not have a launch-ready asset. You have a draft that can cost you review delays, broken onboarding, support tickets, and wasted ad spend.

Quick Scorecard

| Check | Pass criteria | Why it matters | What breaks if it fails | |---|---|---|---| | Domain setup | Primary domain resolves with correct A/AAAA/CNAME records | Reviewers and users must reach the right page | Broken access, wrong brand URL | | HTTPS | SSL valid on all routes with no mixed content | Prevents browser warnings and trust loss | Checkout drop-off, blocked assets | | Redirects | 301s are intentional and loop-free | Keeps SEO and review links stable | Infinite loops, lost traffic | | Email auth | SPF, DKIM, DMARC all pass | Needed for transactional and support email deliverability | Emails land in spam or fail entirely | | Secrets handling | Zero exposed keys in frontend or repo history | Protects billing APIs and admin systems | Account takeover, leaked spend | | API security | Authenticated endpoints enforce authorization and validation | Prevents data exposure in marketplace flows | Unauthorized access or data leaks | | Rate limits | Form/API abuse is throttled | Stops spam and credential stuffing | Support overload, bot abuse | | Performance | LCP under 2.5s and CLS under 0.1 on mobile | Reviewers bounce fast when pages feel slow | Lower conversion and failed review UX | | Monitoring | Uptime alerts + error tracking active | You need to know before customers do | Silent outages and delayed fixes | | Handover docs | Deployment steps and rollback are documented | Lets you maintain without re-breaking prod | Repeat incidents during updates |

The Checks I Would Run First

1. Domain resolution and redirect chain

Signal: the root domain loads the intended landing page in one hop or less from both `www` and non-`www`.

Tool or method: I check DNS records in Cloudflare or your registrar, then test redirects with `curl -I` from multiple regions. I also verify subdomains like `app.`, `api.`, or `checkout.` if your marketplace uses them.

Fix path: I remove accidental chains like `http -> https -> www -> /home -> /`. One clean canonical route reduces review friction and avoids weird SEO behavior.

2. SSL validity and mixed content

Signal: browser shows a secure lock icon on every page state, including forms and embedded assets.

Tool or method: I use Chrome DevTools Security tab plus an SSL checker. Then I inspect console errors for mixed content from images, fonts, scripts, or iframe embeds.

Fix path: move all asset URLs to HTTPS, renew certificates if needed, and force HTTPS at the edge. If third-party scripts still load over HTTP anywhere, I remove them or replace them before launch.

3. Secrets exposure audit

Signal: no API keys, private tokens, webhook secrets, Firebase config leaks with write access, or admin URLs exposed in frontend bundles.

Tool or method: I scan the repo history, built JS bundles, environment files, source maps, CI logs, and browser network calls. I also search for public keys that look harmless but can still trigger costly actions.

Fix path: rotate anything exposed immediately. Move sensitive values into server-side environment variables only.

A simple pattern I expect:

## Example only
NEXT_PUBLIC_ keys stay public
STRIPE_SECRET_KEY stays server-side only

If a key starts doing real work from the browser side, that is a launch blocker.

4. API authorization boundaries

Signal: every protected endpoint checks who the user is and what they are allowed to do.

Tool or method: I test as an anonymous user, a normal user, and a forged user session. Then I try object ID tampering on marketplace records like listings, bookings, payouts, or messages.

Fix path: add server-side authorization checks on every sensitive route. Do not trust hidden form fields or client-side role flags. If one user can read another user's marketplace data by changing an ID in the URL or request body, that is a serious production risk.

5. Email deliverability setup

Signal: SPF includes your sending provider; DKIM signs mail; DMARC policy exists at least at `p=none` for monitoring before tightening later.

Tool or method: I use MXToolbox-style checks plus actual test sends to Gmail and Outlook. Then I inspect headers to confirm authentication passes end-to-end.

Fix path: publish DNS records correctly and wait for propagation before launch. If app review depends on confirmation emails or invite flows but those emails land in spam, your funnel breaks even though the site "works."

6. Edge protection and monitoring

Signal: Cloudflare is active with caching where safe, DDoS protection enabled, uptime monitoring configured on key URLs.

Tool or method: I verify response headers like `cf-cache-status`, test bot protection behavior lightly against form endpoints if relevant as part of abuse defense assessment only within your own property boundaries , then set alerts on uptime plus error rate.

Fix path: cache static assets aggressively but never cache personalized responses by accident. Add alerts for downtime above 2 minutes so you catch problems before app reviewers do.

Red Flags That Need a Senior Engineer

1. You have multiple environments but no clear deployment process.

• That usually means one bad push can break production during review week.

2. Your frontend talks directly to third-party APIs with secret-bearing keys.

• That creates immediate leakage risk if the bundle is inspected.

3. You rely on client-side checks for permissions.

• If roles are enforced only in React state or hidden fields, they can be bypassed.

4. Your forms have no validation beyond "required" fields.

• That invites spam submissions,, bad data quality,, and downstream support load.

5. You cannot explain where rollback happens if deploy day goes wrong.

• Without rollback discipline,, app review delays turn into multi-day revenue loss.

If any two of those are true,, buy help instead of patching blindly.

DIY Fixes You Can Do Today

1. Check your domain from both versions:

• Open `yourdomain.com` and `www.yourdomain.com`.
• Confirm both land on one canonical URL with HTTPS only.

2. Review your environment files:

• Delete any `.env` file from git history if it was committed.
• Move secret values out of frontend variables unless they are truly public by design.

3. Turn on basic Cloudflare protections:

• Enable SSL/TLS full mode where appropriate.
• Turn on caching for static assets.
• Add WAF rules only after testing so you do not block real users by mistake.

4. Test your email reputation:

• Send one message to Gmail and one to Outlook.
• Verify SPF/DKIM/DMARC pass in headers before asking reviewers to click confirmation links.

5. Add uptime monitoring:

• Watch `/`, `/pricing`, `/signup`, `/login`, or whatever route matters most.
• Set alerts to email plus Slack so failures are visible within minutes,.

These fixes will not make a weak architecture safe,, but they will catch obvious launch blockers early.

Where Cyprian Takes Over

This is where Launch Ready saves time compared with DIY guesswork:

| Failure found | What I do in Launch Ready | Timeline | |---|---|---| | Broken DNS or wrong canonical domain | Fix records,, redirects,, subdomains,, propagation checks | Within first 6 hours | | SSL issues or mixed content warnings | Repair certificate setup,, force HTTPS,, clean asset URLs | Same day | | Exposed secrets || rotate keys,, remove leaks,, lock down env vars || Same day | | Weak email deliverability || configure SPF/DKIM/DMARC,, test inbox placement || Same day | | Missing Cloudflare protection || enable edge caching,, DDoS protection,, safe rules || First 24 hours | | Unmonitored production || set uptime monitoring,, error alerts,, handover checklist || First 24 hours | | Deployment uncertainty || ship production build,, validate release flow,, document rollback || By hour 48 |

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 roadmap: https://roadmap.sh/cyber-security
• Cloudflare docs on DNS and SSL/TLS: https://developers.cloudflare.com/dns/
• OWASP API Security Top 10: https://owasp.org/www-project-api-security/

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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.*