ChainMail
Full PIM suite vs focused email client
eM Client is often described as "the best Outlook alternative" — and for good reason. It's a full personal information manager (PIM) with email, calendar, contacts, tasks, and notes all built in. It supports Gmail, Outlook.com, Exchange, iCloud, and generic IMAP. It connects to Gmail via IMAP (with some Google-specific calendar/contacts integration).
ChainMail takes a different approach: it does one thing — email — and builds it specifically for Gmail. It connects through Google's official Gmail API instead of IMAP, which means labels, search, and sync work the way Gmail actually works rather than through protocol translation.
The question is whether you need a full Outlook replacement with calendar and contacts, or a lightweight, private, Gmail-optimized email client.
Where ChainMail wins
Native Gmail API vs IMAP
eM Client connects to Gmail via IMAP. While it handles this better than most clients (it has decent label support), it still runs into the fundamental IMAP-to-Gmail translation issues: search is limited to IMAP capabilities, some label operations behave differently, and Gmail categories don't map cleanly.
ChainMail uses the Gmail API directly. Full Gmail search syntax works (from:boss has:attachment larger:5M after:2026/01/01). Labels work as labels, not folder approximations. Categories, importance markers, and read/unread state all sync accurately.
Privacy and simplicity
ChainMail is local-first with no telemetry, no analytics, and no intermediate servers. Your email goes directly from Google to your machine. There's nothing else running — no calendar sync, no contact sync, no task database — just email.
eM Client is also a local application (not cloud-processed like Spark), which is good. But it's a much larger application with more moving parts — calendar sync, contact sync, task management, and since version 10, cloud-based AI features. More surface area means more potential privacy considerations.
AI drafting with your own API key
ChainMail's AI drafting lets you bring your own API key from OpenAI, Anthropic, Google Gemini, Mistral, and other providers. Your email content goes directly from your machine to the AI provider you chose — ChainMail never touches it.
eM Client added AI features in version 10, but they're processed through eM Client's own cloud service. You don't get to choose your AI provider or use your own key.
Lighter footprint
ChainMail is a focused email client. It starts fast, uses less memory, and doesn't load calendar, contacts, and tasks modules you might not need. If you just want email in a desktop window, ChainMail gives you that without the overhead of a full PIM suite.
More affordable
ChainMail starts at $1/month, $10/year, or $35 for a lifetime license. eM Client's free version limits you to 2 email accounts with a "Free license" watermark on outgoing messages. eM Client Pro costs $49.95 for a one-time license (single major version). Upgrades to future major versions cost extra.
Where eM Client wins
Calendar, contacts, and tasks
This is eM Client's biggest advantage. It has a full calendar with Google Calendar sync, a contacts manager with Google Contacts sync, tasks, and notes — all in one window. If you're replacing Outlook entirely and need everything in one app, eM Client is a much more complete solution. ChainMail is email-only.
Multi-provider support
eM Client handles Gmail, Outlook.com, Exchange/EWS, iCloud, and generic IMAP/POP3 accounts in one unified view. ChainMail is Gmail-only. If you manage email across multiple providers, eM Client is the more flexible choice.
PGP encryption
eM Client has built-in PGP/GPG encryption support for signing and encrypting emails. ChainMail doesn't currently support email encryption beyond what Gmail provides (TLS in transit).
Import tools
Migrating from Outlook? eM Client can import PST files, EML files, and mailbox data from other clients. It also supports drag-and-drop migration. ChainMail doesn't need import tools (your email is already on Gmail's servers), but if you have local archives to preserve, eM Client handles that.
More mature, cross-platform
eM Client has been around since 2007 and runs on both Windows and macOS. It has a large user base, regular updates, and a comprehensive feature set refined over nearly two decades. ChainMail is newer, currently in beta, and Windows-only (Mac planned).
| Feature | eM Client | ChainMail |
|---|---|---|
| Gmail API integration | ✕ IMAP | ✓ Native Gmail API |
| Gmail labels (true labels) | Partial (decent IMAP mapping) | ✓ |
| Gmail search operators | Limited (IMAP search) | ✓ Full Gmail syntax |
| Non-threaded message view | ✓ | ✓ |
| AI email drafting | ✓ Cloud-processed | ✓ BYOK, local |
| Smart templates with variables | Basic templates | ✓ Variables + attachments |
| Calendar | ✓ Full Google Calendar sync | ✕ |
| Contacts | ✓ Full Google Contacts sync | ✕ |
| Tasks & Notes | ✓ | ✕ |
| PGP encryption | ✓ | ✕ |
| Multiple email providers | ✓ Gmail, Exchange, IMAP | ✕ Gmail only |
| Platforms | Windows, macOS | Windows (Mac planned) |
| PST/EML import | ✓ | ✕ |
| Privacy (no telemetry) | Local app (AI is cloud-based) | ✓ Fully local, BYOK AI |
| Price (lifetime) | $49.95 (single version) | $35 (all updates) |
| Free tier | 2 accounts, watermark | 7-day free trial |
| Dark mode | ✓ | ✓ |
Who should pick ChainMail?
- Gmail-only users who just want email — if you don't need calendar, contacts, or tasks in your email client, ChainMail is lighter and more focused
- Privacy-first users — ChainMail's BYOK AI drafting and zero-telemetry architecture keeps your data between you and Google
- People who want native Gmail search — full Gmail query syntax works because ChainMail uses the Gmail API, not IMAP
- Budget-conscious users — $35 lifetime with all updates vs $49.95 for a single major version
- Users who want AI choice — pick your own AI provider and API key instead of being locked to one vendor
Who should stick with eM Client?
- Users replacing Outlook entirely — if you need email + calendar + contacts + tasks in one app, eM Client is a full PIM suite
- Multi-provider users — if you have Gmail, Exchange, and iCloud accounts that need to coexist
- Users who need PGP encryption — eM Client has built-in PGP support
- macOS users — eM Client runs on Mac today; ChainMail is Windows-only for now
- Users migrating from Outlook with local archives — eM Client's PST import tools make the transition smoother
Frequently Asked Questions
Is ChainMail cheaper than eM Client?
Yes. ChainMail's lifetime license is $35 and includes all future updates. eM Client Pro is $49.95 for a single major version — upgrading to the next major version (e.g., v10 to v11) costs extra. ChainMail also offers $1/month and $10/year plans.
Does eM Client use the Gmail API?
No. eM Client connects to Gmail via IMAP for email. It does use Google's APIs for calendar and contacts sync, but email itself goes through IMAP, which limits search capabilities and label handling compared to ChainMail's native Gmail API connection.
Can I switch from eM Client to ChainMail?
Yes. Your email is stored on Gmail's servers, so there's nothing to migrate. Sign in with your Google account in ChainMail and everything syncs automatically. Note that calendar, contacts, and tasks won't carry over because ChainMail is email-only — those stay accessible through Google's web apps or other PIM tools.
Does eM Client have a free version?
Yes, but it's limited to 2 email accounts and adds a "Free license" watermark to your outgoing emails. ChainMail offers a 7-day free trial with no watermarks or limitations.
Which is better for a team migrating from Outlook to Google Workspace?
It depends. If your team needs calendar and contacts in the same desktop app, eM Client is the closer Outlook replacement. If your team just needs a familiar desktop email layout connected to Gmail (and they'll use Google Calendar in the browser), ChainMail offers a simpler, cheaper, more Gmail-accurate experience.