ImprovMX doesn't host your inbox. We offer advanced[1] email forwarding to your existing inbox (Gmail, Outlook, etc.), with the option to send via SMTP.

Fastmail is a paid hosted mailbox service: they provide the inbox, so you receive, read, and send mail in Fastmail.

Your choice largely depends on if you need a hosted inbox or prefer to use your existing inbox.

ImprovMX
Fastmail
Customer Support
Live Human & AI Chatbot Support
Email support via ticket submission
Free plan
Free forwarding for one domain. Paid plans for scale.
Paid service only (after 30-day trial)
Mailbox hosting
No mailbox hosting, forwards to existing inbox.
Hosted mailbox with contacts plus calendar
API
API to manage forwarding, domains and aliases
API manages mailbox
CLI/MCP
Offers an official CLI.[2]
Does not offer a CLI nor MCP.
Apps
Just a web app.
Web and mobile apps
Setup
Must setup DNS records for forwarding and sending
Easy inbox creation, but a hassle to migrate
Advanced Forwarding
Webhooks
Inbound emails can fire webhooks requests
No webhook support
Logging/Analytics
Offers detailed mail logs and log retention > 7 days
No mail log view—troubleshooting is difficult
Compliance
ImprovMX is GDPR compliant
Fastmail is GDPR compliant
2. ImprovMX's CLI is built for terminal workflows, automation, and ai coding tools like Claude Code and OpenAI Codex.
Questions? Reach out to us, we love chatting about email service providers.

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