All three apps put your email in a native-feeling Mac window, and all three can show several accounts in one inbox. Where they differ is in which accounts they support, what runs on someone else’s server, and how you pay. Apple Mail, which comes with every Mac, is the baseline any of them has to beat.
Short version: if you work with a team and want shared inboxes, shared drafts and an AI assistant, or you need the same app on iPhone, Android and Windows, Spark is the stronger choice. If every account you have is Gmail and you want an app that uses Gmail’s own labels, filters and aliases, Mimestream is built for exactly that. If you have several IMAP mail accounts and want a one-time purchase that needs no account and no sync service, Oxid Mail is the one to try, bearing in mind it is still in beta and has no Google or Microsoft sign-in yet: each account needs a password or an app password.
At a glance
| Oxid Mail | Spark | Mimestream | |
|---|---|---|---|
| Price | $39 one-time, one Mac | Free; Plus $10/month or $99/year; Pro $20/month or $199/year, per user | $49.99/year or $4.99/month, 14-day trial |
| Accounts | Multiple IMAP accounts that sign in with a password or app password; no Google or Microsoft sign-in (OAuth) yet; changes written back over IMAP | IMAP, iCloud, Exchange, Outlook, Yahoo, Google | Gmail only, through the Gmail API |
| Platforms | Mac | iOS, Android, Mac, Windows | Mac (macOS 12 or later) |
| Unified inbox | Inbox, Sent, Archive and Trash across every account | Yes | Yes, optional |
| Undo send, scheduled send, snooze | Undo send and snooze; scheduled send only while Oxid Mail is open; snooze applies on this Mac only | Yes | Undo send and snooze; scheduled send not listed on its features page as of October 2026 |
| AI assistant | Optional; a built-in model (a separate download) or your own Ollama, on your Mac | Spark +AI, via Azure OpenAI Service | Not listed on its features page as of October 2026 |
| Mail data on the vendor’s servers | None: no Oxid account and no sync service; it talks to your mail servers directly | Some, for notifications, Send Later and team features | No intermediary sync service; connects straight to Gmail |
| Team features | None | Shared inboxes, shared drafts, comments, delegation | Group plan for billing and seats |
Where your mail goes
This is the biggest practical difference, and each vendor documents it.
Spark keeps your mail on your provider’s server (Gmail, Outlook and so on) rather than its own, but it does use its own cloud for several features. Its privacy page says that for Gmail, Outlook and Yahoo it stores an application-specific token, and for AOL, Exchange and custom IMAP accounts “this access token is your email login and password.” To send notifications it stores the subject and part of each message, encrypted, and deletes it four hours after the notification. Send Later and the team features also store messages on its servers, which are hosted by Google in the US. When you use Spark +AI, your prompt and the relevant email content go to Azure OpenAI Service, which Spark says does not train on it and keeps it for no more than 30 days.
None of that is unusual for a cross-platform app with push notifications and shared inboxes; it’s how those features work. It’s a trade you may well be happy to make.
Mimestream says it “only stores your data and tokens on your device” and connects directly to the Gmail API “without going through any intermediary sync service” (mimestream.com). Its privacy policy adds that the app does send some device and account details, such as your email address and notification settings, to its own servers.
Oxid Mail has no account and no sync service: it connects straight to your own mail servers, and your mail isn’t stored anywhere else. Search and the optional AI assistant both run on your Mac. Read, star, archive and delete actions are written back to your mail server over IMAP, and if the connection drops they’re replayed once it returns. The app does make a few other connections: a licence check to oxidapps.com, a lookup of your domain’s mail settings when you add an account (including Mozilla’s public settings database), and the download of the optional AI model. None of these sends your mail.
Because there is no server, a scheduled message goes out only while Oxid Mail is running. If your Mac is asleep or the app is closed at the scheduled time, it waits until you open it again. Spark and Apple Mail don’t have that limit.
Accounts and features
Mimestream’s focus on Gmail is a strength if Gmail is all you use. It works with Gmail labels, server-side filters, aliases, templates and calendar invitations, and blocks tracking from over 75 services (features). It doesn’t support other providers.
Spark covers the widest range of providers and adds a lot on top of the basics: a Smart Inbox that sorts mail, screening of new senders, follow-up reminders, and translation (sparkmailapp.com). The paid plans add team collaboration, including shared inboxes for addresses like sales@, shared drafts and 10 GB of team file storage per member (pricing). For teams, that’s a real reason to choose it.
Oxid Mail is aimed at one person with several IMAP mailboxes. Besides the unified Inbox, Sent, Archive and Trash, it has send-as identities with a signature for each, cross-account guards when sending, and per-account colours, ordering and a pause switch. It doesn’t yet support Google or Microsoft sign-in, so a Gmail account needs an app password, and a Microsoft 365 account that only allows modern sign-in won’t work at all. It’s in beta, so expect rough edges that Spark and Mimestream, both long established, are less likely to have.
And Apple Mail?
Apple Mail is free, supports most providers and already does a lot: it can schedule a send, undo a send, and remind you about a message later. It also has All Inboxes and Smart Mailboxes that span accounts, built-in Google and Exchange account types, and Apple Intelligence summaries and Smart Reply on Macs that support it. If it already works for you, you may not need any of these apps. People usually look elsewhere for a unified view that behaves the way they want, for per-account identities, or for team features.
Price
Spark’s free plan covers unlimited accounts and its Smart Inbox, so you can use it for nothing. Plus costs $10 a month or $99 a year per user, and Pro costs $20 a month or $199 a year (pricing). Mimestream is $49.99 a year or $4.99 a month, covering up to five devices and family sharing (pricing).
Oxid Mail costs $39 once, for one Mac, with no renewal. That’s less than one year of Mimestream or Spark Plus. It’s also part of the $99 Value Pack, which includes 12 Oxid apps.
Which should you choose?
- Choose Spark if you work in a team, want shared inboxes and AI drafting, need the same app on iPhone, Android or Windows, need Google or Microsoft sign-in, want scheduled mail to go out while your Mac is off, or are happy with its free plan.
- Choose Mimestream if every account you have is Gmail and you want labels, filters and aliases to work the Gmail way.
- Choose Oxid Mail if you have several IMAP accounts that accept a password or app password, want your mail handled on your Mac with no account or sync service, and prefer paying once. Try it with the beta caveat in mind.
- Stay with Apple Mail if it already does what you need, including built-in Google and Exchange sign-in, send later and Remind Me.
Questions
What is a good Spark Mail alternative for Mac?
If every account you have is Gmail, Mimestream is built for that. For several IMAP accounts, Oxid Mail is $39 once and needs no account or sync service. It is still in beta and has no Google or Microsoft sign-in yet, so each account needs a password or app password.
Spark vs Mimestream: which is better?
Spark covers the widest range of providers, runs on iOS, Android, Mac and Windows, and adds team features and an AI assistant, with a free plan. Mimestream is Gmail only, works with Gmail labels, filters and aliases, and costs $49.99 a year or $4.99 a month.
Is there a Mimestream alternative that isn't Gmail only?
Spark supports IMAP, iCloud, Exchange, Outlook, Yahoo and Google. Oxid Mail works with multiple IMAP accounts that sign in with a password or app password; a Gmail account needs an app password, and a Microsoft 365 account that only allows modern sign-in won't work.
Which Mac email app keeps my mail private?
Oxid Mail has no account and no sync service: it connects straight to your mail servers, and search and the optional AI assistant run on your Mac. Mimestream connects directly to the Gmail API without an intermediary sync service. Spark stores some data on its servers for notifications, Send Later and team features.
Does Oxid Mail support scheduled send?
Yes, but only while Oxid Mail is open. Because there is no server, if your Mac is asleep or the app is closed at the scheduled time, the message waits until you open it again. Spark and Apple Mail don't have that limit.