Stop worrying about spam folders and missed connections. Letterbox is your reliable SMTP service built for developers, marketers, and teams who need every message to land where it counts — the inbox.
lightweight, developer-friendly SMTP solution that integrates seamlessly into your stack.
Built-in support for popular frameworks.
Sandbox mode for testing without sending live emails.
Detailed logs and real-time delivery status.
Scalable from side project to production.
Ensure your app's emails land where they should — fast, secure, and trackable.
High deliverability for transactional & system emails.
SPF, DKIM & DMARC authentication out of the box.
Uptime and performance monitoring dashboard.
Webhooks for real-time user interaction tracking.
Built to handle millions of emails without breaking a sweat — performance, reliability, and control at scale.
Optimised SMTP infrastructure for bulk email delivery.
Adaptive throttling to meet ISP requirements.
Dedicated IPs and warm-up assistance.
Enterprise-grade SLAs and 24/7 support.
Our pricing is crafted to scale with you — giving your business the reliability, support, and deliverability you need, without overpaying for what you don’t need.
Up to 50,000 emails
Shared IP pool
SMTP & API access
Basic email analytics (opens, bounces)
SPF/DKIM configuration help
7-day log retention
Email-only support
Up to 500,000 emails
High-performance shared IPs
Advanced analytics
Webhooks and event tracking
30-day log retention
Premium support (email + chat)
Dedicated onboarding specialist
2M+ emails/month
Dedicated IPs with automated warm-up
Inbox placement monitoring & reputation tools
Priority queueing and smart rate-limiting
90-day log retention
24/7 priority support (chat, email, phone)
SLA-backed deliverability & uptime guarantees
Whether you’re sending thousands or millions, top-performing companies rely on Letterbox for consistent, high-impact email delivery.
Trusted by 87,000+ users worldwide 
