DuoDiscover
Spark Mail
Unified inbox from Readdle with message and inbox side by side when unfolded
Spark Mail is built for iPhone Duo (it uses the fold, Split View or the outer display) as of .
About this app
Spark Mail is an email client from Readdle that brings Gmail, Outlook, iCloud, Yahoo, AOL and any IMAP account into one unified inbox. Its Smart Inbox puts messages from people ahead of newsletters and notifications, which are grouped below. Everyday tools include marking emails as done, setting them aside for later, muting threads, scheduled sending that works even when the device is off, and Smart Search with Smart Folders. Gatekeeper lets users screen first-time senders, and priority senders can be pinned to the top. Spark +AI can summarize long threads, draft and rephrase replies, adjust tone and translate messages. The app also connects calendars, links to tools such as Notion, Asana and Things, and offers team features including shared drafts, private comments, message assignment and shareable links to individual emails. Spark is free to download, with paid plans for its premium and team features. Version 3.20.1, released on October 22, 2026, is Readdle's iPhone Duo update. The developer says the inbox and an open message can be shown side by side, the same actions are available whether the phone is closed, open or partly folded, and unfolding gives more room for reading, writing, search and calendar.
Features
- Unified inbox for Gmail, Outlook, iCloud and IMAP accounts
- Smart Inbox grouping newsletters and notifications
- Gatekeeper for screening new senders
- Scheduled send, snooze and mute
- Spark +AI summaries, drafting and translation
- Built-in calendar
- Inbox and message side by side on unfolded iPhone Duo
How it uses iPhone Duo
Readdle's release notes for Spark 3.20.1 say the app is ready for iPhone Duo from launch day. On the unfolded display, the inbox and the open message can appear side by side. Readdle says the same actions and content are available whether the phone is closed, open or partially folded, and that unfolding gives more space for reading, writing, search and the calendar. DuoDiscover has not yet tested it on an iPhone Duo.
Compatibility
| Tier | Built for Duo |
|---|---|
| Uses the fold | Yes |
| Category | Productivity |
| Price | Free + IAP |
| Verified | · developer statement |
| Added |
What the tiers mean: Understanding iPhone Duo app compatibility ›
Developer
Spark Mail is developed by Readdle Technologies Limited.
Official website: sparkmailapp.com
Get the app
Discuss Spark Mail in r/iPhoneduoapp ›
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Spark Mail on iPhone Duo: FAQ
Is Spark Mail optimized for iPhone Duo?
Yes. Spark Mail is Built for Duo (Made for iPhone Duo): it uses the fold, Split View or the outer display. Verified on October 22, 2026 (developer statement).
What does Spark Mail look like on iPhone Duo unfolded and folded?
Readdle's release notes for Spark 3.20.1 say the app is ready for iPhone Duo from launch day. On the unfolded display, the inbox and the open message can appear side by side.
How much does Spark Mail cost?
Spark Mail costs Free + IAP on the App Store.
