Automate Your Deliveries with
Transactional SMTP
No inboxes. No webmail. Just pure, high-volume sending infrastructure. Perfect for password resets, OTPs, invoices, and app notifications. Ensure your critical emails hit the inbox instantly.
Built for Apps, Engineered for Scale.
Integrate seamlessly with your existing stack. Let our infrastructure handle the heavy lifting while you focus on building.
Plug & Play Integrations
Connect your applications in minutes with standard SMTP relay credentials. No complex API endpoints required to get started.
Bulletproof Deliverability
We strictly enforce email authentication protocols and maintain high IP reputation so your critical alerts always reach the inbox, not the spam folder.
Complete Visibility
Never guess if an email arrived. Monitor your application's sending health in real-time with comprehensive logs and bounce reports.
High-Volume Delivery, Simple Pricing.
Choose the perfect relay plan for your application. No hidden fees, just lightning-fast automated email delivery.
Relay Starter
Perfect for small apps sending basic notifications and password resets.
- 10,000 Emails / month
- 100 Emails / hour
- Standard SMTP Relay
- SPF, DKIM & DMARC
- TLS / SSL Encryption
- Basic Delivery Reports
- Reputation Monitoring
- Standard Port Access
- Advanced Bounce Reports
- Dedicated IP Address
Relay Pro
The sweet spot for growing CRMs, ERPs, and active e-commerce stores.
- 100,000 Emails / month
- 500 Emails / hour
- Premium SMTP Relay
- SPF, DKIM & DMARC
- TLS / SSL Encryption
- Advanced Delivery Reports
- Reputation Monitoring
- Real-Time SMTP Logs
- Detailed Bounce Reports
- Dedicated IP Address
Relay Scale
For enterprise-level applications requiring massive, instantaneous throughput.
- 1,000,000 Emails / month
- Unlimited Emails / hour
- Enterprise SMTP Relay
- SPF, DKIM & DMARC
- TLS / SSL Encryption
- Advanced Delivery Reports
- Reputation Monitoring
- Real-Time SMTP Logs
- Detailed Bounce Reports
- Dedicated IP Included
Connects to Everything. Instantly.
Whether you are powering a WHMCS billing system, a WooCommerce store, or a custom application, integrating S4Hosting's Transactional SMTP takes less than 60 seconds.
Complete Sending Visibility.
Never guess if your critical alerts arrived. Get real-time insights, granular SMTP logs, and immediate bounce classifications right in your dashboard.
Real-Time SMTP Logs
Track every single connection attempt, authentication process, and delivery status as it happens. Perfect for rapid troubleshooting and app debugging.
Delivery & Bounce Reports
Monitor your inbox placement rates. We automatically classify hard bounces vs. soft bounces so you can keep your list clean and reputation high.
Queue & Reputation Monitoring
We actively monitor your sending reputation and rate limits. If a recipient server slows down, our intelligent queues hold and retry your emails automatically.
- 🟢 Live Reputation: Excellent
- 🟢 Active Queues: 0 Pending
- 🟢 Anti-Abuse Shield: Active
Frequently Asked Questions
Everything you need to know about our Transactional SMTP infrastructure, limits, and sending policies.
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