SSL Certificate & Domain Expiry Monitor
Add your domains once and get alerts before SSL certificates or domain registrations expire, with a monthly summary you can forward to clients.
Economics
- Pricing example
- $4/month for 25 domains; $15/month for 250 domains (agency)
- Daily math
- $20/day is about $600/month, e.g. 75 users x $4 + 20 agencies x $15 = $600/month.
- Target if you hit the daily math
- Target: $600 / month at about 95 paying users
Audience and urgency
Audience: Freelance web developers and small agencies managing many client domains, and IT admins at SMEs.
Urgency: An expired certificate or domain takes a client's website or email offline, and the agency usually gets the blame. Renewal emails often go to an old inbox or get filtered as spam.
MVP scope
- ✓ Bulk-add domains; check certificate expiry via a TLS handshake and domain expiry via RDAP
- ✓ Daily checks with alerts at 30, 14, 7 and 1 days by email and Telegram
- ✓ Client tags and a monthly summary email or PDF per client
- ✓ Flags for certificate name mismatch and incomplete certificate chains
- ✓ Stripe tiers by number of domains
Omitted features
- - Do NOT build full uptime or page-content monitoring in Day 1
- - Do NOT auto-renew domains or connect to registrar accounts
- - Do NOT scrape WHOIS where RDAP data is available
Suggested stack
- Frontend
- Next.js + Tailwind CSS
- Backend or API
- Scheduled Node worker (small VPS, Fly.io or Cloud Run job) + Postgres
- Payments
- Stripe Billing
- Hosting
- Vercel for the app; Fly.io or Cloud Run for the daily checker
Repository metadata
- Blueprint ID
ssl-domain-expiry-monitor- Category ID
dev_tools- Monetization ID
micro_subscription
Day-one distribution
Channels
- Reddit r/webdev and r/sysadmin
- WordPress and web agency communities
- A free one-off 'check my domains' page that shows expiry dates without signup
Reddit strategy
Share the free checker page with a short note on why renewal emails get missed.
Cold outreach or directory hook
Offer agencies a free month on the 250-domain plan if they import their client list during the trial.
Search keywords
ssl expiry monitor, domain expiry alert, check ssl certificate expiration date bulk
One-shot master prompt
Build an "Expiry Monitor" SaaS with Next.js, Tailwind CSS, Postgres and a Node worker. Core requirements: 1. Domain management: add one or bulk-paste many, assign client tags, and see a table with SSL expiry date, issuer, days left, domain expiry date, registrar and status colour. 2. Worker runs daily: open a TLS connection on port 443 (Node tls module) to read the certificate's validTo, subject names and chain validity; query domain expiry via RDAP (using the IANA bootstrap file to find each TLD's RDAP server). Record errors without crashing the batch. 3. Alerts at 30, 14, 7 and 1 days by email (Resend) and Telegram bot, one per threshold, plus alerts for name mismatch or chain errors. 4. Monthly summary per client tag as an email and a PDF the user can forward. 5. Stripe Billing tiers ($4 for 25 domains, $15 for 250). A public /check page lets anyone check up to 5 domains without signing up.
Comparable products
Published 2026-10-08.
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