How I Would Fix emails landing in spam in a Lovable plus Supabase automation-heavy service business Using Launch Ready.

How I Would Fix emails landing in spam in a Lovable plus Supabase automation-heavy service business Using Launch Ready

The symptom is usually simple: your signup, onboarding, invoice, or automation emails are "sent" but never get seen. In an automation-heavy service business, that means missed leads, delayed delivery, broken customer trust, and more support tickets than you planned for.

The most likely root cause is not "email content" alone. It is usually a sender identity problem: bad DNS auth, sending from the wrong domain, weak reputation, or Supabase/email provider settings that do not match the domain setup. The first thing I would inspect is the full sending path: the exact From address, the SMTP or email API provider, and whether SPF, DKIM, and DMARC are aligned on the live domain.

Triage in the First Hour

1. Check one real message header from a spammed email.

• Look for SPF pass/fail.
• Look for DKIM pass/fail.
• Look for DMARC pass/fail and alignment.

2. Inspect the sending account in your email provider.

• Confirm the verified domain.
• Confirm the From address matches that domain.
• Confirm there are no sandbox or trial limits still active.

3. Review Supabase auth and automation flows.

• Check password reset, magic link, welcome email, invoice email, and notification triggers.
• Confirm which function or edge function sends each message.

4. Open DNS records for the domain.

• Verify SPF TXT record.
• Verify DKIM CNAME or TXT records.
• Verify DMARC TXT record.
• Check for duplicate SPF records or conflicting mail records.

5. Check Cloudflare settings if it sits in front of the app.

• Make sure mail-related DNS records are not proxied when they should be DNS-only.
• Confirm no redirect rules are interfering with verification links.

6. Inspect logs in Supabase and your mail provider.

• Look for 4xx/5xx delivery errors.
• Look for rate limits, blocked recipients, or authentication failures.

7. Test one fresh send to Gmail and Outlook.

• Use a new seed inbox if possible.
• Compare inbox placement versus spam placement.

A fast diagnosis flow looks like this:

Root Causes

1. SPF is missing or wrong.

• Confirm by checking the message header for `spf=fail` or `softfail`.
• Also confirm there is only one SPF record per domain. Multiple SPF TXT records often break validation.

2. DKIM is not signing correctly.

• Confirm by checking `dkim=fail` in headers.
• Then verify that the selector in DNS matches what your provider expects.

3. DMARC is too strict before alignment is correct.

• Confirm by checking `dmarc=fail` or quarantine/reject policies with poor alignment.
• If you recently changed domains or providers, this is a common break point.

4. You are sending from a mismatched domain or subdomain.

• Example: app emails come from `no-reply@gmail.com` while your product uses a branded domain.
• Or Supabase is configured with one sender domain while your automation tool uses another.

5. Reputation is damaged by volume spikes or bad lists.

• Confirm by looking at bounce rates, complaint rates, and sudden send bursts after launch.
• Automation-heavy businesses often trigger many messages at once, which can look suspicious to mailbox providers.

6. Links, redirects, or content look risky to filters.

• Confirm by reviewing subject lines, URL shorteners, tracking domains, repeated phrases, and broken links in templates.
• If Cloudflare redirects or preview links are inconsistent, spam filters can penalize that pattern.

The Fix Plan

I would fix this in layers so I do not create a bigger outage while trying to improve deliverability.

1. Lock down the sender identity first.

• Use one branded sending domain only for production mail if possible.
• Make sure every automated email uses the same verified From address and reply-to strategy.

2. Repair DNS authentication in this order:

• SPF: authorize only the actual sending service(s).
• DKIM: enable signing with 2048-bit keys if available.
• DMARC: start with `p=none`, collect reports, then move to `quarantine`, then `reject` once alignment is stable.

3. Separate transactional mail from marketing mail.

• Transactional messages should come from a dedicated subdomain like `mail.yourdomain.com`.
• Do not mix cold outreach with password resets and onboarding emails on the same stream.

4. Audit Supabase automations end to end.

• Trace every trigger: signup hook, database webhook, edge function, cron job, workflow step.
• Remove duplicate sends and retry loops that may be blasting recipients multiple times.

5. Clean up templates and links.

• Keep HTML simple and mobile-safe.
• Use one primary CTA per email where possible.
• Replace suspicious redirect chains with direct HTTPS links on your branded domain.

6. Reduce burst risk during recovery.

• Throttle high-volume automations for 24 to 72 hours if reputation is poor.
• Warm up gradually instead of resending everything at once.

7. Set up monitoring before you call it done.

• Track bounce rate, complaint rate, delivery errors, open trends where available, and inbox placement tests on Gmail and Outlook accounts.

If I need to inspect DNS quickly from terminal or CI logs:

dig txt yourdomain.com
dig txt _dmarc.yourdomain.com
dig txt selector._domainkey.yourdomain.com

That gives me a fast read on whether the live records match what Supabase and your email provider expect.

Regression Tests Before Redeploy

Before I ship anything back into production, I want clear pass/fail checks.

• Send test emails to at least 3 inboxes:

1. Gmail 2. Outlook/Hotmail 3. One third-party mailbox if available

• Verify message headers show:
• SPF pass
• DKIM pass
• DMARC pass
• Alignment between From domain and authenticated domain

• Test all critical automation paths:

1. New signup welcome email 2. Password reset 3. Magic link login 4. Invoice or receipt email 5. Internal notification email

• Check for duplicate sends:
• Trigger each event once and confirm only one message arrives.

• Validate mobile rendering:
• Open on iPhone-sized viewport and desktop Gmail view.
• Confirm CTA buttons work without zooming or layout breakage.

• Review failure handling:
• If the email provider times out, does Supabase retry safely?
• If retries happen, do they avoid duplicate customer emails?

Acceptance criteria I would use:

• Zero SPF/DKIM/DMARC failures on test messages sent from production config.
• No duplicate automated emails across five repeated test runs per flow.
• Inbox placement improved from spam to inbox on at least two major providers before full rollout.
• Bounce rate under 2 percent during retest window if list quality is healthy enough to measure it accurately.

Prevention

This problem comes back when teams treat email as an afterthought instead of part of production infrastructure.

1. Add code review checks for every mail-related change.

• Any change touching sender config, templates, retries, cron jobs, or webhook handlers needs review before deploys go live.

2. Treat secrets as production assets.

• Store SMTP/API keys only in environment variables or secret managers.
• Rotate leaked keys immediately if they ever appear in Lovable exports or shared screenshots.

3. Add basic observability. - Track send count, bounce count, complaint count, and provider error codes daily.

4. Keep API security tight around automations because this stack can be abused fast:

• Authenticate every admin-only trigger
• Validate inputs before sending any email
• Rate limit public forms and webhooks
• Log safely without exposing tokens or personal data
• Use least privilege for service roles in Supabase

5. Set UX expectations properly.

• Tell users when verification emails may take up to 60 seconds
• Show resend states clearly
• Provide fallback help when inboxes do not receive mail

6. Watch performance too because slow systems get messy under load:

• Queue bursty automations instead of firing everything inline
• Avoid retry storms
• Profile p95 latency on send endpoints so spikes do not cascade into duplicates

When to Use Launch Ready

Use Launch Ready when you need me to fix this without turning it into a two-week guessing game.

It fits best if you have:

• A Lovable-built front end connected to Supabase
• Automation-heavy flows already live or about to go live
• Emails that must work for onboarding, billing, alerts, reminders, or internal ops
• A founder deadline where broken deliverability means lost revenue within days

• Domain setup cleanup
• Email authentication review: SPF/DKIM/DMARC
• Cloudflare DNS checks
• Production deployment verification
• Environment variables and secrets audit
• Uptime monitoring setup
• Handover checklist so your team knows what changed

What you should prepare before I start: 1. Access to Supabase project settings and logs 2. Access to your domain registrar and Cloudflare account 3. Access to your email provider dashboard 4. A list of all automated email types currently live 5. One example of an email that landed in spam plus its full headers if available

If you want me to move fast without breaking production again later, book here: https://cal.com/cyprian-aarons/discovery

References

1. Roadmap.sh API Security Best Practices: https://roadmap.sh/api-security-best-practices 2. Roadmap.sh QA: https://roadmap.sh/qa 3. Roadmap.sh Cyber Security: https://roadmap.sh/cyber-security 4. Google Postmaster Tools Help: https://support.google.com/mail/answer/9981691 5. RFCs for SPF/DKIM/DMARC overview via Cloudflare Learning Center: https://www.cloudflare.com/learning/email-security/dmarc-dkim-spf/

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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.*