K-9 Mail vs Nine (2026): which should you pick?
As of Nov 13, 2026, K-9 Mail grades higher than Nine: 2.8 against 2.4 out of 4.0.
Checked Nov 13, 2026 · graded Nov 13, 2026 by ToolGPA
K-9 Mail grades higher on the free plan and features. Nine grades higher on platforms. They get the same grade on value for money and ease of use.
Price, platforms and features side by side. The table says where each price was read and when.
Nine
Exchange ActiveSync email, calendar and tasks app for phones
Free trial · from $14.99 one-time
Which one is for you
Pick K-9 Mail if
- Fits if you read several mailboxes on one Android phone
- Works for people who want GPG and open-source code
Look elsewhere if
- Not for you if you use iPhone or a computer, as it is Android only
- Watch out: the site's banner says Thunderbird for Android is the future of K-9 Mail
- Skip it if you need a new address, since it is a client for existing mailboxes
- Tight if you want setup done for you, as you add your own account details
Pick Nine if
- Fits if your work mailbox runs on Exchange or Office 365 and you read it on a phone
- Works for people who want to pay once for a mail app
Look elsewhere if
- Skip it if you want calendar and tasks from an IMAP mailbox, as those need ActiveSync
- Skip it if you need a desktop or web app too
- Watch out: the price comes from the Google Play listing, which also shows in-app purchases
- Watch out: Nine Work, the enterprise edition, was Android-only, with iOS described as coming
- Watch out: Play lists a different developer name from the vendor site
How we grade them
| 2.8GPAK-9 MailGood | 2.4GPANineFair | |
|---|---|---|
| Value for money | AFree to download under the Apache 2.0 licence, with no paid plans, and a donate link. | A$14.99 once is well under a year of what the typical email app charges per month ($7.95), and there's no subscription to keep paying. |
| Free plan and trial | AThe full app is free from Google Play, F-Droid, GitHub or Amazon. | CA two-week trial and then you buy the licence. The Google Play listing doesn't say whether the trial wants a card. |
| Features | BPush IMAP, GPG and PGP/MIME, a unified inbox, identities and message tools. The listing shows no gap in the core job of a mail client, though it provides no address of its own. | CExchange ActiveSync with mail, calendar, contacts and tasks, plus widgets and folder push. The gap is that IMAP accounts get mail only, so it's an Exchange tool first. |
| Ease of use | CNo store rating on record. You add your accounts and server settings yourself. | CNo store rating on record. You connect each account, and for a company mailbox that can mean device-management settings. |
| Platforms and integrations | DAndroid only: no iPhone, desktop or web version is listed. | CAndroid and iPhone only, with Exchange, Office 365, Intune and AirWatch as the connections. No desktop app and no web version. |
| Best for | an open-source Android email client | Exchange mail on an Android or iPhone |
The GPA is the average of the five grades: an A is 4 points, an F is none. The full reasons are on each tool's page: K-9 Mail and Nine. How we grade
Where they differ
- K-9 Mail is open source, according to its own site.
- Nine can be bought with a one-time purchase.
- Nine also covers tasks and calendar.
In commonAndroidEmail client
At a glance
| K-9 Mail | Nine | |
|---|---|---|
| Pricing | Free | Free trial |
| Starts at | Free | $14.99 one-time license |
| Free plan | Free to download from Google Play, F-Droid, GitHub Releases or Amazon; no paid plans are listed. | None |
| Free trial | None listed | 2-week free trial before buying a license |
| iOS | ||
| Android | ||
| Made by | K-9 Mail | JiranSoft |
| Price read from | k9mail.app | play.google.com |
| Checked | Nov 13, 2026 | Nov 13, 2026 |
Worth knowing
K-9 Mail
- Android only; no iOS, desktop or web version is listed.
- The site's banner says Thunderbird for Android is available now and calls it the future of K-9 Mail.
- It is a client for existing mailboxes and does not provide an email address.
Nine
- IMAP accounts sync email only; calendar, contacts, tasks and notes need ActiveSync.
- The price comes from the app's Google Play listing, whose wording may be out of date, and the listing also shows in-app purchases.
- Nine Work, the enterprise edition, was Android-only with iOS products described as coming.
- Play lists NextIntelligence.ai as the developer, while the vendor site is branded JiranSoft.
Key features
K-9 Mail
- Push IMAP
- The feature list names push IMAP support, so new messages can arrive without polling on servers that allow it.
- GPG and PGP/MIME
- The site lists GPG and PGP/MIME support for signing and encrypting messages.
- Unified inbox and identities
- A unified inbox, per-account notifications and multiple identities are listed, along with signatures and BCC to self.
- Message handling tools
- Listed tools include message flagging, keyboard shortcuts, attachment saving and emoji support.
- Several ways to install
- The download page offers the Play Store (with a beta channel), F-Droid, GitHub Releases and Amazon.
Nine
- Exchange ActiveSync
- Direct Push sync with Exchange Server 2003 SP2 through 2019, Office 365 and Exchange Online, with modern authentication for Office 365.
- Email, calendar, contacts and tasks
- Calendar and contacts tie into the phone's stock apps, with task and notes sync on supported Exchange versions.
- Security features
- The listing names S/MIME, client certificates, IRM, SSL and a global address list for corporate accounts.
- Device-only data
- The listing says Nine has no server for user data, connecting directly to the user's server and storing data on the device.
- Widgets and folder push
- Widgets for unread count, shortcuts, email list, tasks and calendar agenda, plus per-folder push notifications.
Plans
K-9 Mail
Free$0
Open source under the Apache License 2.0; the site has a donate link.
Nine
Nine license$14.99
one-time per license
Full app after a 2-week trial, as stated on the Google Play listing.
Common questions
Which is cheaper, K-9 Mail or Nine?
As of Nov 13, 2026, K-9 Mail is free, and Nine starts at $14.99 one-time license.
Which has a free plan, K-9 Mail or Nine?
As of Nov 13, 2026, only K-9 Mail has a free plan. Nine does not, though it has a free trial.
Which platforms do K-9 Mail and Nine run on?
As of Nov 13, 2026, only Nine lists an iOS app. Both list an Android app. A platform missing from a listing is one its maker's pages did not mention.
More comparisons
How this page was made
- The verdict at the top follows a fixed rule. When both tools are in the same category and either is in our top three for it, the verdict follows that ranking: the higher-placed tool is our pick. The top three weigh who each tool suits as well as its grades, so a pick can go against the GPA. Otherwise the page does not pick one and says which grades higher: the higher GPA first; on a tie, the one with a free plan, then the one that starts cheaper in dollars a month, counted the same way for both; if they are still level, what the choice depends on.
- The grades are our own, from each tool’s review or report card. The GPA is their average.
- Prices, plans and platforms come from each tool’s listing. The table above says where each price was read and when.
- The differences and the answers to the questions are worked out from those listings.