Migrating from Mailgun:
Escape the Legacy Tax
Mailgun was great in 2014. In 2026, it is suffering from "Interface Rot" and "Support Decay." You are paying enterprise rates for legacy software.
Mailgun has become a legacy provider with decaying support and a complex, outdated UI. Modern developers are switching to Transmit + SES for better security (IAM vs API Keys) and 90% cost savings.
- Mailgun support tickets often go unanswered for days, leaving you stranded during outages.
- Their pricing model is opaque and punished by 'Overage' multipliers.
- Migrating suppression lists and reputation to AWS SES is easier than you think.
- Transmit provides a modern, 'Vibe Coding' friendly interface for the same underlying email standards.
01. The Support Vacuum
The number one reason users leave Mailgun isn't even price. It's fear.
Fear that if something goes wrong on a Friday night, nobody will answer the phone. Mailgun's support has been hollowed out by private equity acquisitions.
Transmit takes a different approach. We are engineers. When you open a ticket, you aren't talking to an outsourced Tier 1 agent reading a script. You are talking to the team that built the platform.
02. API Keys are Legacy Security
Mailgun, like SendGrid, relies on Long-Lived Static API Keys. You generate a key `key-12345...` and paste it into your production environment variables.
If that key leaks, your reputation is destroyed.
Transmit uses AWS IAM Roles. We don't want your keys. We want a temporary, revocable permission to send on your behalf. This is zero-trust architecture.
- Mailgun: Hardcoded secrets. High risk.
- Transmit: `sts:AssumeRole`. credential rotation is handled automatically by AWS.
03. The Migration Path
How to move without losing reputation
Export Suppression List
Don't email people who bounced on Mailgun. Export your `bounces` and `complaints` tables.
Verify Domain on SES
Add 3 CNAME records to your DNS. Takes 5 minutes.
Import Bounces to Transmit
Upload your Mailgun suppression CSV to Transmit. We will automatically block sends to those users.
04. The Data Rescue Operation
Before you cancel, you must extract your suppression data. Mailgun makes this UI hard to find, but the API is open. Run this immediately:
Upload this `json` file during your Transmit onboarding to ensure you don't damage your new AWS reputation.
Legacy vs Modern Architecture
Legacy (Mailgun)
- Support Vacuum (Days to reply)
- Static API Keys (Security Risk)
- Opaque "Overage" Pricing
Modern (Transmit)
- Engineer-to-Engineer Support
- IAM Roles (Zero Trust)
- Pass-through AWS Pricing
Securing the Landing
Escaping Mailgun is only half the battle. Once you land on AWS SES, ensure your infrastructure is secure and your delivery is transparent.