Building a Warmup Engine for AWS SES
The AWS SES 'Sandbox' is a catch-22 for new developers. Transmit automates the reputation-building process, moving from 0 to 1M emails without the manual overhead of legacy gatekeepers.
- ISPs junk sudden traffic spikes; warmup mimics natural growth.
- Postmark requires manual approval for 300k+; Transmit uses automated logic.
- Real-time SNS feedback monitoring for <0.1% complaint rates.
- Exponential ramp-up curves are baked into the 'Glass Box' pipeline.
Amazon SES is arguably the most powerful and cost-effective email service on the planet. But for new domains, it presents a catch-22: you need a reputation to send volume, but you need volume to build a reputation.
The Sandbox Reality
Every new SES account starts in a "Sandbox." Even after you get production access, AWS doesn't just let you blast 100,000 emails. Your quota starts low and increases based on your health metrics. But ISPs like Gmail and Outlook are even stricter. If they see a sudden spike from a domain they've never seen before, they junk it.
bounceRate and complaintRate in real-time. If AWS SES signals a failure, the governor instantly throttles the campaign to protect your domain reputation. Legacy providers like Postmark force you to wait for a support ticket; we let the logic lead.Under the Hood
The engine is built using Cloudflare Workers and a distributed KV store to track daily counters with sub-millisecond latency. Every time a message is sending, we check the global warmup state for the domain.
By automating this process, Transmit users can focus on writing content, while the infrastructure handles the delicate dance of sender reputation.
Technical Prerequisites
Warmup is only effective if your infrastructure is sovereign. Ensure your connection layer is secure before ramping up volume.