What Is the OBM Engine?

The OBM Engine is the core sending infrastructure behind Mission Inbox. It handles:

• Email delivery and routing
• IP management and warmup
• Real-time event tracking via webhooks
• Automatic scaling based on volume
• Pre-send spam filtering via MI Shield integration

API Specifications

Integration takes under 5 minutes. Full API documentation is available in the dashboard.

Rate Limiting & Throttling

Mission Inbox applies intelligent rate limiting to protect sender reputation:

• Automatic throttling based on IP warmup stage
• Volume caps per hour and per day (configurable)
• Smart queuing for high-volume sending
• Configurable throttling per API key

Infrastructure Per API Key

Each API key gets dedicated infrastructure:

• Dedicated IP addresses
• Separate sending infrastructure
• Protected sender reputation
• Automatic warmup and optimization
• No cross-contamination between API keys

This is critical for platforms that serve multiple customers — each customer's API key operates on isolated infrastructure.

Two Sending Methods

Method 1: SMTP Mailboxes (Starter + Pro)

• Standard SMTP protocol
• Works with any email client or sales engagement platform
• Included in both Starter ($199/month) and Pro ($599/month) plans
• 30 mailboxes included in Starter, discounted mailboxes on Pro

Method 2: API Sending via OBM Engine (Pro Only)

• RESTful API with SDKs
• Programmatic email sending
• Webhook event tracking
• Sandbox testing environment
• Requires Pro plan ($599/month)
• Built for developers and platforms

Scaling Behavior

• 100 emails/month — Works with zero configuration
• 100K emails/month — Automatic scaling, no changes needed
• 1M emails/month — Same infrastructure, same latency
• 100M+ emails/month — Enterprise scale, contact sales for custom setup

No infrastructure changes required at any volume. Pay only for what you use.

White-Label Option

Developers can white-label the OBM Engine to power email features inside their own SaaS product. This means the end user sees the developer's brand, not Mission Inbox.

Monitoring & Analytics

• Real-time delivery logs
• Detailed analytics dashboard
• 30-day log retention (standard)
• 100% tracking on every email
• API-first monitoring and debugging
• Custom reporting via API endpoints

API Sending Pricing

Who Uses API Sending

• Developers building email into applications
• Platforms providing email infrastructure to their users
• SaaS companies sending transactional emails, notifications, and user communications
• Startups that need to scale without worrying about infrastructure
• Enterprises requiring programmatic email at 50M+ scale

Updated on: 27/02/2026