Quick Verdict
Spark Mail is the best email client if you juggle multiple accounts across different providers. Made by Readdle (the team behind PDF Expert and Documents), Spark supports Gmail, Outlook, iCloud, Yahoo, and any IMAP account in a single unified inbox — plus has solid AI triage, smart drafts, and cross-platform apps that actually work on every OS.
What It Is
Spark is a cross-platform email client that's been around since 2015 and added AI features in 2023-2025. It's the only major email client that treats multi-account use as a first-class citizen: your Gmail work, iCloud personal, and Outlook side-project all live in one unified inbox, with separate lanes and shared AI features.
Key Features
- Unified multi-account inbox: Gmail, Outlook, iCloud, Yahoo, Exchange, any IMAP.
- Smart Inbox: auto-categorizes into Personal, Notifications, Newsletters, Pinned.
- AI draft + rewrite: compose with AI assist; rewrite tone and length.
- Cross-platform apps: iOS, Android, Mac, Windows, Web — all feature-complete.
- Shared drafts and team inboxes: on paid plans.
- Send later, snooze, reminders: standard productivity features.
Pricing
Spark is free for individuals with basic AI, $5/month for Premium (unlimited AI + advanced features), and $8/user/month for Teams. Cheaper than Shortwave, and the free tier is substantially usable.
Pros & Cons
Pros: Best multi-account experience in any email app. All major providers supported. True cross-platform parity. Solid free tier. Team inboxes actually work.
Cons: AI features are less sophisticated than Shortwave or Superhuman. Less keyboard-dense than power-user tools. Gmail-specific features (labels, multiple inboxes) don't port perfectly.
Who Should Use It
Spark is ideal for users with 2+ email accounts across different providers, teams that want shared email features, and anyone who works across iOS, Android, Mac, and Windows and needs the same experience everywhere. Not the right choice for single-Gmail power users (use Shortwave or Superhuman).
Verdict
Spark Mail earns our Best Multi-Account Client pick. It's not the flashiest AI email client, but it's the most practical for the millions of people who juggle personal and work email across different providers.