Launch Ready API security Checklist for AI-built SaaS app: Ready for first 100 users in bootstrapped SaaS?.

What "ready" means for a bootstrapped SaaS trying to reach the first 100 users

For an AI-built SaaS app, "launch ready" does not mean perfect. It means a stranger can sign up, verify their email, use the core workflow, and not expose your data, your customers data, or your admin keys in the process.

For the first 100 users, I would define ready as this: no critical auth bypasses, zero exposed secrets, SPF/DKIM/DMARC passing, SSL enforced everywhere, p95 API latency under 500ms on the main user flows, monitoring alerts working, and a rollback path that does not depend on luck. If any of those are missing, you do not have a launch problem only. You have a support load problem, a trust problem, and possibly a breach problem.

For bootstrapped SaaS, the business risk is simple. One bad deployment can break onboarding for days, one leaked key can create an invoice you did not plan for, and one broken email setup can kill activation before the user ever logs in. This checklist is built for founders who want to get to 100 users without spending weeks guessing where the weak spots are.

Quick Scorecard

| Check | Pass criteria | Why it matters | What breaks if it fails | | --- | --- | --- | --- | | HTTPS everywhere | All app pages and APIs force SSL with no mixed content | Prevents credential theft and browser warnings | Login friction, insecure sessions | | Secrets hygiene | No API keys in code, logs, or client bundles | Stops data leaks and billing abuse | Account takeover, vendor charges | | Auth hardening | Protected routes require valid session or token checks | Blocks unauthorized access to customer data | Data exposure, support escalations | | Role checks | Admin actions require explicit authorization | Prevents privilege escalation | Users editing or deleting other users data | | Rate limiting | Login and API endpoints are rate limited | Reduces brute force and abuse risk | Credential stuffing, cost spikes | | CORS policy | Only trusted origins can call sensitive APIs from browser apps | Prevents cross-site abuse from random domains | Token theft paths, data leakage | | Email deliverability | SPF, DKIM, and DMARC all pass | Makes signup and reset emails reliable | Users never verify accounts | | Monitoring | Uptime alerts and error tracking are live | Lets you detect failures before users do | Silent downtime, slow incident response | | Deployment safety | Production deploy has rollback and environment separation | Reduces launch risk from bad releases | Broken app after deploy | | Logging discipline | Security events are logged without secrets or PII dumps | Helps investigate issues safely | Blind incident response or leaked logs |

The Checks I Would Run First

1) Authentication is actually enforced on every sensitive route

Signal: I look for any endpoint that returns user data without checking session validity or token claims. In AI-built apps, this usually shows up as one forgotten server action or one public API route that was copied from a demo.

Tool or method: I test with an expired token, no token at all, and a token from another user. I also inspect middleware, route guards, and backend authorization checks instead of trusting only frontend redirects.

Fix path: Move auth checks to the server side first. Then add explicit allowlists for public routes like landing pages and health checks. If the app has admin functions, I separate them into role-based permissions now rather than later.

2) Secrets are not leaking into GitHub, client code, or logs

Signal: I search for `API_KEY`, `SECRET`, `PRIVATE_KEY`, service tokens, webhook signing keys, and `.env` values in code history and build artifacts. If anything sensitive is visible in the browser bundle or pasted into logs, that is a launch blocker.

Tool or method: Use GitHub secret scanning if available. Run a repo-wide search plus a build inspection of bundled frontend assets. Check runtime logs for accidental request body dumps.

Fix path: Move all secrets to environment variables on the server only. Rotate anything that may have been exposed already. If there is any doubt about exposure duration, assume compromise and replace it before launch.

A simple pattern helps here:

## server-only
OPENAI_API_KEY=...
STRIPE_SECRET_KEY=...
DATABASE_URL=...

## never expose these to frontend bundles

3) Rate limits exist on login, signup, password reset, and expensive APIs

Signal: If someone can hammer login 500 times in a minute or trigger expensive AI calls repeatedly without friction, your costs will climb fast and abuse will follow.

Tool or method: I send repeated requests with a script or an API client like Postman/curl. I check whether failed logins slow down after repeated attempts and whether expensive endpoints have per-user limits.

Fix path: Add per-IP and per-account throttles on authentication endpoints. Put usage caps on AI-heavy routes. For bootstrapped SaaS with first 100 users coming from ads or cold outreach, this matters because one bot can waste more than your monthly hosting budget.

4) CORS is locked down to known origins only

Signal: A wildcard CORS policy on authenticated APIs is usually too loose for production unless you truly understand why it is safe. If any site can call your browser-accessed API with credentials allowed broadly, that needs review.

Tool or method: Inspect server CORS config directly. Test requests from unauthorized origins in a browser-like context.

Fix path: Allow only your production domain and required subdomains. Separate public unauthenticated endpoints from private authenticated ones. If you need multiple environments or marketing domains later," add them deliberately instead of opening everything now.

5) Email deliverability passes before you invite users

Signal: Signup confirmation emails land in spam or never arrive at all. That usually means SPF/DKIM/DMARC are missing or misaligned.

Tool or method: Send test emails through Gmail and Outlook accounts. Check DNS records with your provider's validation tools. Confirm DMARC reports are being received if configured.

Fix path: Set SPF to authorize only your sender. Enable DKIM signing through your email provider. Set DMARC policy to at least `quarantine` once alignment is stable. For first-time founders who depend on magic links or password resets," bad email setup can make the product look broken even when the app works fine.

6) Monitoring catches failures before users do

Signal: You should know within minutes if signup fails," if webhook processing breaks," or if uptime drops below target. If you only notice issues when someone posts on X or emails support," you are already behind.

Tool or method: Verify uptime monitoring hits both homepage and key app endpoints every few minutes. Trigger a test alert by taking down a staging endpoint briefly." Confirm error tracking captures exceptions with enough context but without leaking secrets.

Fix path: Set alerts for availability," elevated 5xx rates," failed jobs," payment webhook failures," and auth errors." Add one dashboard that shows launch health in plain language so you do not need to dig through five tools during week one."

Red Flags That Need a Senior Engineer

If you see any of these," I would stop DIYing this part and bring in Launch Ready instead of shipping blind:

1. You have no idea which environment variables are safe to expose versus server-only. 2. Your app uses AI tools that can read user input but has no prompt injection defense. 3. You cannot explain who is allowed to see admin data versus customer data. 4. Your deployment process has no rollback plan if login breaks after release. 5. You already found one secret in git history," browser code," or shared screenshots.

The reason is simple." These are not cosmetic issues." They create real business damage: failed onboarding," support tickets," broken trust," wasted ad spend," chargebacks," downtime," and possible data exposure."

DIY Fixes You Can Do Today

1. Turn on HTTPS redirects everywhere Force all traffic through SSL." Make sure `http://` always lands on `https://` with one canonical domain."

2. Review every `.env` value Separate frontend-safe values from server-only secrets." If you are unsure about one value," keep it server-side until reviewed."

3. Check DNS records for email Verify SPF,DKIM,and DMARC pass before sending transactional mail." This alone often fixes "my signup email never arrived" complaints."

4". Limit dangerous endpoints manually Even basic throttling on login,password reset,and AI-heavy routes reduces abuse immediately." Start with conservative limits rather than none."

5". Add uptime monitoring tonight Monitor homepage,status page,and core API health every 1-5 minutes." A free tool is enough for day one if it sends alerts reliably."

Where Cyprian Takes Over

Here is how checklist failures map to delivery:

| Failure area | What I fix in Launch Ready | Timeline | | --- | --- | --- | | Domain misconfigurations | DNS setup,directs,and subdomains across prod paths" |- Day 1 | | SSL issues / mixed content |- Cloudflare + SSL enforcement + redirects |- Day 1 | | Weak email deliverability |- SPF/DKIM/DMARC alignment |- Day 1 | | Secret exposure risk |- Environment variables,secrets cleanup,and handover notes |- Day 1-2 | | Broken deployment flow |- Production deployment verification + rollback notes |- Day 2 | | Missing monitoring |- Uptime monitoring,error visibility,and alert routing |- Day 2 | | Cache / performance basics |- Cloudflare caching rules,DDoS protection,- static asset handling |- Day 2 | | Handoff gaps |- Production checklist so you know what was changed |- End of sprint |

If I find exposed secrets,no auth checks,wildcard CORS on private APIs,bad email alignment,and no monitoring at the same time,I treat that as launch-blocking." That combination turns early growth into avoidable incidents."

References

• 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 Docs - SSL/TLS overview: https://developers.cloudflare.com/ssl/
• Google Workspace - SPF,DKIM,and DMARC basics: https://support.google.com/a/topic/2752442

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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.*