Launch Ready API security Checklist for AI-built SaaS app: Ready for investor demo in marketplace products?.

Launch Ready API security Checklist for AI-built SaaS app: Ready for investor demo in marketplace products?

"Ready" for an investor demo is not "it works on my machine." For an AI-built SaaS app in a marketplace context, ready means a stranger can sign in, connect a payment or marketplace account, hit the core API flows, and not expose data, break auth, or fall over under light real-world traffic.

If I were self-assessing this product, I would want four things true before I put it in front of investors:

• No exposed secrets in code, logs, or client-side bundles.
• No critical auth bypasses or broken object-level authorization.
• Core API requests return a p95 under 500ms on normal demo load.
• Domain, email, SSL, and monitoring are live so the product looks and behaves like a real company.

For this service context, Launch Ready is the 48-hour sprint I would use to get the foundation safe and presentable: domain, email, Cloudflare, SSL, deployment, secrets, caching, DDoS protection, SPF/DKIM/DMARC, uptime monitoring, and a handover checklist.

Quick Scorecard

| Check | Pass criteria | Why it matters | What breaks if it fails | |---|---|---|---| | Auth | Every protected route and API returns 401/403 correctly | Prevents unauthorized access | Data leaks, investor demo embarrassment | | Authorization | Users only access their own records | Stops cross-account data exposure | Marketplace trust failure | | Secrets | Zero secrets in repo, frontend bundle, or logs | Protects keys and tokens | Account takeover, billing abuse | | Input validation | All API inputs are validated server-side | Blocks malformed and malicious requests | Broken flows, injection risk | | Rate limiting | Sensitive endpoints have limits per IP/user/token | Reduces abuse and brute force | Demo outage, cost spikes | | CORS/CSP | Only approved origins can call APIs; CSP is set | Limits browser-based attacks | Token theft, script injection | | Email auth | SPF, DKIM, DMARC all pass | Keeps mail out of spam and spoofing down | Lost invites, failed verification emails | | SSL/redirects | HTTPS enforced with clean redirects | Protects sessions and trust signals | Browser warnings, SEO damage | | Monitoring | Uptime alerts and error tracking are active | Detects failures before investors do | Silent downtime during demo | | Performance | p95 API under 500ms; LCP under 2.5s on key pages | Keeps the demo fast and credible | Slow clicks, dropped conversions |

The Checks I Would Run First

1. Authentication coverage

• Signal: I look for any endpoint that returns data without a valid session or token.
• Tool or method: Postman or curl against every protected route with no token, expired token, and another user's token.
• Fix path: Enforce auth at the middleware layer first. Then add tests that fail if any protected route returns 200 without identity.

2. Object-level authorization

• Signal: A user can guess another record ID and still read or update it.
• Tool or method: Try swapping IDs in URL params and request bodies across users in staging.
• Fix path: Check ownership on every object fetch and mutation. Do not rely on frontend hiding buttons.

3. Secret exposure scan

• Signal: API keys appear in Git history, client bundles, environment dumps, or error logs.
• Tool or method: Search repo history with git grep plus secret scanners like Gitleaks or TruffleHog.
• Fix path: Rotate anything exposed immediately. Move all sensitive values to server-side env vars and revoke old tokens.

4. CORS and browser trust

• Signal: Any origin can call your authenticated API from a browser.
• Tool or method: Inspect response headers and test from a random origin with fetch requests.
• Fix path: Allow only known domains. If you need multiple environments, list them explicitly.

5. Rate limiting on high-risk endpoints

• Signal: Login, password reset, invite creation, webhook handlers, and search endpoints accept unlimited requests.
• Tool or method: Send repeated requests with a simple script or Postman runner.
• Fix path: Add per-IP and per-user limits. Put stricter limits on auth endpoints than read-only ones.

6. Email deliverability setup

• Signal: Verification emails land in spam or fail authentication checks.
• Tool or method: Check SPF/DKIM/DMARC with MXToolbox or Google Admin tools if available.
• Fix path: Publish correct DNS records before launch. For investor demos tied to marketplace onboarding flows this is non-negotiable.

example.com TXT "v=spf1 include:_spf.google.com ~all"
_dmarc.example.com TXT "v=DMARC1; p=quarantine; rua=mailto:dmarc@example.com"

Red Flags That Need a Senior Engineer

1. You cannot explain where secrets live If nobody can say where production keys are stored and rotated from end to end, I would not ship it myself.

2. Auth works only because the frontend hides links That is not security. It means one direct request can bypass the UI entirely.

3. Marketplace webhooks are unverified If Stripe-like events or partner callbacks are accepted without signature checks, anyone can forge state changes.

4. The app has no meaningful logs If an investor clicks through something breaks and you cannot trace the request ID quickly enough to diagnose it within minutes of failure.

5. You have already seen one "small" leak One exposed key usually means more hidden issues in env handling, deployment config, or client-side bundling. That is when DIY becomes expensive.

DIY Fixes You Can Do Today

1. Rotate every production secret you can list Start with database credentials, third-party API keys, webhook secrets, JWT signing keys if they were ever shared broadly.

2. Delete secrets from the repo history if they were committed Removing the file is not enough. Revoke the old value first because Git history still has it.

3. Turn on HTTPS-only redirects Make sure all HTTP traffic goes to HTTPS at the edge so nobody sees mixed-content warnings during the demo.

4. Add basic environment separation Keep dev and prod credentials separate. A founder mistake I see often is one shared Supabase/Firebase/Stripe sandbox setup being used too widely.

5. Test three bad cases manually Try:

• no token,
• expired token,
• another user's ID.

If any of those succeed where they should fail with 401 or 403 then your launch risk is real.

Where Cyprian Takes Over

If your checklist shows gaps across security plus launch infrastructure then Launch Ready is the fastest path I would recommend instead of piecing together random fixes over several weekends.

Here is how failures map to deliverables:

| Failure area | What I fix in Launch Ready | Timeline | |---|---|---| | Domain not configured correctly | Domain setup plus DNS records plus redirects plus subdomains | Within 48 hours | | Email failing deliverability checks | SPF/DKIM/DMARC setup and validation | Within 48 hours | | SSL warnings or mixed content issues | Cloudflare + SSL + forced HTTPS + caching rules | Within 48 hours | | Secrets scattered across codebase | Environment variables cleanup plus secret handling review | Within 48 hours | | No production deployment path | Production deployment hardening and handover checklist | Within 48 hours | | No uptime visibility | Monitoring setup with alerting basics enabled | Within 48 hours | | Weak edge protection for public launch traffic | Cloudflare DDoS protection plus safe caching defaults | Within 48 hours |

For an AI-built SaaS app in a marketplace segment I would treat these as minimum acceptance criteria before handoff:

• Zero exposed secrets confirmed by scan.
• No critical auth bypasses found in manual testing.
• SPF/DKIM/DMARC passing for outbound mail.
• p95 API latency under 500ms for core demo flows.
• Uptime monitoring active with alerts going to at least one real inbox or phone number.

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 Roadmap: https://roadmap.sh/cyber-security
• OWASP API Security Top 10: https://owasp.org/www-project-api-security/
• 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.*