What is imapsync?

imapsync is a command-line utility developed by Gilles Lamiral, designed to synchronize emails between two IMAP servers. It’s an extremely powerful and reliable tool used by thousands of system administrators, email providers, and tech-savvy users around the world.

Whether you’re moving to a new hosting provider, consolidating inboxes, or running regular backups, imapsync gets the job done.

---

How does imapsync work?

In simple terms, imapsync connects to a source IMAP account and a destination IMAP account, and copies all messages from one to the other — including folders, flags, and metadata.

It’s smart enough to only copy what’s missing, making it great for incremental syncs or retrying interrupted transfers.

---

Basic commands to use imapsync manually

Once installed, the basic syntax of imapsync looks like this:

imapsync \
–host1 old.mailserver.com –user1 [email protected] –password1 secret1 \
–host2 new.mailserver.com –user2 [email protected] –password2 secret2

Here’s what each parameter means:

• –host1 / –host2: source and destination IMAP server addresses
• –user1 / –user2: the email account usernames
• –password1 / –password2: passwords

💡 Full documentation and download: https://imapsync.lamiral.info/

Why imapsync is so powerful

• ✅ Mature and battle-tested over many years
• 💾 Handles large inboxes and attachments without issues
• 🔁 Supports incremental syncs (ideal for retries)
• 🔐 Works with SSL, TLS, and modern authentication
• 🧠 Robust error handling and detailed logs

And best of all, it just works.

The developer, Gilles Lamiral, has done a fantastic job building and maintaining this tool, making it an essential resource for anyone handling email infrastructure.

---

How IMAPly uses imapsync under the hood

At IMAPly.com, we believe in building on solid foundations.

That’s why we chose to integrate imapsync as the core engine behind our migration platform. But instead of asking our users to manually run complex CLI commands, we built an automated layer around it that handles everything:

---

Going beyond the CLI: What IMAPly adds

Here’s what IMAPly adds on top of imapsync:

✅ Web-based interface	No need for command-line — upload your accounts file
🔐 Password validation	Tests IMAP logins before attempting migration
🚀 Parallel migrations	Uses Docker Swarm to run multiple jobs simultaneously
📊 Real-time progress tracking	Monitor transfers live with ETA and status updates
♻️ Retry logic & error recovery	Automatically retries failed syncs
📄 Reports & logs	Get clear feedback on what happened during the sync

In other words, IMAPly wraps the power of imapsync into a scalable, user-friendly system — ideal for web hosts, sysadmins, and SaaS platforms.

---

Final thoughts

If you enjoy working on the command line and love control, imapsync is an amazing tool that gives you everything you need. We highly recommend it.

If you want something that works out of the box — with dashboard, batch support, error handling, and no shell scripting — then IMAPly builds on top of imapsync to make migrations easy for everyone.

Try IMAPly for free while we’re in beta: https://imaply.com

And once again:

Thank you to Gilles Lamiral for building such an incredible open-source foundation. 🙌

Introduction

Migrating email accounts between servers is often a necessary but daunting task — especially when you’re dealing with thousands of messages, attachments, and multiple users. If your current provider isn’t cutting it, or you’re consolidating systems, a secure and efficient IMAP migration is essential.

In this post, we’ll break down the key concepts, common pitfalls, and best tools (including IMAPly) to make your migration process seamless.

---

Why IMAP Email Migrations Matter

IMAP (Internet Message Access Protocol) allows users to access emails stored on a remote mail server. It’s widely used by email providers like Gmail, Outlook, Zimbra, Roundcube, and many others.

But what happens when:

• You’re moving to a new hosting provider?
• Your organization is consolidating mail servers?
• You need to migrate hundreds of accounts without losing a single email?

That’s where a robust IMAP migration strategy becomes critical.

---

Common Challenges with IMAP Transfers

Migrating IMAP accounts isn’t as simple as copying files. You might face:

• ✉️ Lost or duplicated emails
• 🐌 Slow transfers when dealing with large mailboxes
• 🔐 Authentication errors
• 🧩 Different folder structures across providers
• 🛑 Downtime or access issues during migration

To overcome these, automation and smart queuing are essential.

---

Key Features to Look for in an IMAP Migration Tool

When evaluating migration tools, look for:

• ✅ Secure transfer protocol (SSL/TLS support)
• 🚀 Parallel migrations to handle hundreds of accounts at once
• 🕒 Progress tracking and estimated time remaining
• 🔄 Full folder and label replication
• 🧠 Retry logic for unstable connections

That’s exactly what IMAPly was built to handle.

---

Step-by-Step: How IMAPly Makes Email Migration Simple

1. Upload your email accounts list via an easy-to-use spreadsheet format
2. Select your source and target servers – we support Gmail, cPanel, Zimbra, Outlook, and custom IMAP
3. IMAPly creates a secure tunnel using encrypted connections (SSL/TLS)
4. Migrations run in parallel
5. Real-time feedback is displayed so you can monitor progress
6. Get a detailed report once your transfer is done

💡 IMAPly uses imapsync under the hood, enhanced with a real-time overlay system — so you don’t need to modify the original tool to get advanced monitoring.

---

Final Tips for a Smooth Transition

• Make sure IMAP access is enabled on both source and destination servers
• If using Gmail, generate an App Password or use OAuth2
• Schedule your migrations outside business hours for less disruption
• Don’t delete old accounts until you’ve confirmed full transfer

---

Conclusion

Migrating IMAP email accounts doesn’t have to be a nightmare. With the right tool and a clear process, you can move thousands of mailboxes securely and efficiently — without downtime or data loss.

Whether you’re a sysadmin, business owner, or just managing a team’s move, IMAPly can save you hours of manual work and give you peace of mind.