Honest comparisons with the email clients we respect.

How we approach a comparison

Comparison pages on the open web tend to be one of two things: an affiliate funnel that flatters the writer’s product into a strict superset of every other product, or a thin matrix of green ticks and red crosses that hides the judgement calls behind a checkbox. We’d like to write neither.

Each page under /mail/<client>-alternative/ is written in the first person. Where the other client is better, we say so plainly. Where Epistles is the right pick, we say that too, and we say for whom, because no email client is right for everyone. We don’t claim parity on a feature we haven’t shipped. The rough rule we follow: if a Newton, Spark, or Superhuman user read our page about their current client and came away thinking we were unfair to it, we’d rewrite the page.

One sentence of positioning, said once, then we let the comparisons speak for themselves: Epistles exists because no other client unified all five of the providers we use, on all five of the platforms we use, with local-first storage and a zero-knowledge vault for the credentials that move between devices. If that sentence describes a problem you have, the pages below are for you.

Comparisons with other email clients

Seven pages, written and live. They’re the comparisons readers ask for most often.

Epistles vs Newton Mail

Newton was the unified, keyboard-aware, multi-account client a generation of power users loved without qualification, and it shut down twice. The page names the four things Newton got right, the parts Epistles already inherits, the parts we still owe its old users (snooze, send-later, richer sender profiles), and where we deliberately go further (local-first, zero-knowledge sync, Linux as a first-class build). It’s a love letter, not a takedown.

Epistles vs Mimestream

Mimestream is the most polished Gmail-API-native Mac client we’ve used, and if you live entirely in Gmail and entirely on macOS, it’s an excellent choice. The page is honest about that. Where Epistles answers a different question is the multi-provider matrix (Gmail, Microsoft 365, Fastmail, ProtonMail, IMAP) and the cross-platform one (macOS, Linux, iOS, Android shipping today). Same Gmail-API protocol underneath; different scope.

Epistles vs Spark Mail

Spark is a multi-account client too, with team features (shared drafts, comments) we don’t have. The architectural difference is that Readdle’s servers fetch a portion of incoming messages to power push notifications, hold team-feature data, and keep account tokens. Epistles is local-first with a zero-knowledge vault that holds only opaque credential ciphertext. If team collaboration is your priority, Spark. If server-side mail data gives you pause, ours.

Epistles vs Superhuman

Superhuman is $33 a month, with a real human onboarding call, an AI-summarisation surface, and a famously fast keyboard model. Epistles is $35 a year, with no AI, no concierge, and a keyboard model in the same tradition. If the AI features and the white-glove onboarding are the draw, Superhuman is the honest answer. If the price gap matters, or if you need Linux, Android, Fastmail, Proton, or IMAP in the same client, this is where we land.

Epistles vs Canary Mail

Canary picked AI as a productivity multiplier, and built a multi-account, multi-platform client around that thesis. Epistles deliberately doesn’t have AI features because local-first and zero-knowledge are real architectural constraints. We don’t send your mail to a model provider, and we have no plans to. If AI summaries and writing assistance are the draw, Canary. If the model-in-the-middle gives you pause, ours.

Epistles vs Thunderbird

Thunderbird is the closest in spirit on Linux: open source, cross-platform, long-lived, multi-account, with Thunderbird for Android (formerly K-9) shipping today. The differences are native protocols (we use Gmail API, MS Graph, JMAP, Proton with OpenPGP rather than IMAP for everything), iOS today, and a Cloud Vault for cross-device credential sync. Our source isn’t open yet; theirs has been for two decades. The page is honest about that asymmetry.

Epistles vs Mailbird

Mailbird is the most polished Windows-first multi-account client, with deep third-party app integrations (Slack, Asana, etc.) docked into the mail chrome. Epistles is a different kind of cross-platform: Mac, Linux, iOS, and Android today, with native protocols and a zero-knowledge Cloud Vault. Email is the job here, not a hub. If Windows is your daily driver and you want app integrations in the mail window, Mailbird. If the inbox lives everywhere your phone does, ours.

Using specific email providers in Epistles

These pages are about getting the best out of a particular email service, in a client that also holds your other accounts. Each one is a different shape of question, and a different answer.

Use Gmail in Epistles

Gmail is the service. Epistles is a client that speaks Gmail’s native API rather than flattening to IMAP, so labels stay labels, categories stay categories, server-side filters stay editable, and aliases behave the way Gmail intends. Plus your Outlook, Fastmail, Proton, and IMAP accounts in the same window.

Use Microsoft 365 in Epistles

Microsoft 365 is the service. Epistles speaks MS Graph natively, the forward-compatible API. Microsoft is blocking EWS for Exchange Online starting October 2026, with full retirement April 2027; any third-party client still on EWS faces a forced rewrite. Epistles is already on the right side of that line, plus push via OWA SignalR, plus your other accounts in the same window.

Use Fastmail in Epistles

Fastmail is the service, and they invented JMAP, the modern protocol that IMAP should have become. Fastmail’s own desktop app is a wrapper around the web app; Epistles is a real native JMAP client on Mac, Linux, iOS, and Android, plus your other accounts.

Use Proton Mail in Epistles, no Bridge

Proton Mail is the service. Until now, third-party clients required Proton Bridge (a separate desktop app, not available on iOS or Android, paid-tier only). Epistles is the first third-party client to support Proton accounts directly, with no Bridge and no extra software, on Mac, Linux, iOS, and Android. The OpenPGP keys live in your OS keychain only and never touch the Cloud Vault, by design.

Comparisons coming soon

The pages below are scheduled but not yet written. Until each one ships, here is the honest two- or three-sentence framing we’d give you over email if you wrote in to ask.

Epistles vs HEY (coming)

HEY is a different thesis entirely: a workflow rebuild on a fresh domain, with the Imbox / Feed / Paper Trail vocabulary and the Screener up front. People who love that vocabulary love it deeply, and we’d send you there if it sounded right. Epistles is the other answer, the one for people who want their existing Gmail, Fastmail, and Microsoft 365 accounts as they are, in a client that doesn’t ask them to learn new nouns for an inbox.

Epistles vs Airmail (coming)

Airmail’s Mac integration runs deep, and its plugin system has unusual third-party hooks we don’t replicate. Update cadence has been slow since the 2020 subscription pivot, and that’s a fair question to ask. Epistles is in active development with a public changelog, ships on Linux and Android in addition to Mac and iOS, and stores everything locally in SQLite.

Epistles vs Apple Mail (coming)

Apple Mail is built into the operating system, free, and well-tuned for iCloud and Gmail accounts. For a Mac-and-iPhone user with one or two mailboxes, it’s genuinely fine. Where Epistles fits is multi-provider depth on the providers Apple Mail flattens to IMAP (Microsoft 365 via MS Graph, Fastmail via JMAP, ProtonMail via its own protocol), and platforms beyond the Apple side (Linux, Android).

Epistles vs Spike (coming)

Spike turns email into a chat-style timeline, with messages collapsed into conversational bubbles and the headers tucked away. Some people love it and their love is real. Epistles is the opposite design choice: traditional editorial email, with subjects, signatures, threads, and a composition surface that treats a long email as a long email.

Clients we considered and didn’t list

A few products you might expect to see here don’t have a page on the roadmap, for plain reasons.

• Outlook (the client itself, on Mac and Windows). The audience for “should I switch from the Outlook app to a third-party client” is largely solved by the existing Microsoft and Mimestream comparisons; a dedicated page would mostly recapitulate them.
• Inbox by Google. Google retired it in 2019. People still search for replacements, and our Newton page covers most of that audience already; a dedicated Inbox page would be addressing a six-year-old absence with thinner traffic than it earns.
• Mailspring. An honest case: Mailspring is open source, cross-platform, and we read its source while building parts of our own feature set. The audience overlap is real but small, and we’d rather cite it in the engineering blog than pretend our products are in head-to-head competition.
• Edison Mail. Edison’s 2020 disclosure that they monetised user inbox data through their analytics arm is a public matter of record; we don’t want a page whose argument writes itself.
• Polymail. Update cadence has been quiet for years, and we don’t want to litigate that without solid signal that the team is still active. If the project picks back up, we’ll add a page.

If we’re missing one

If the client you’re weighing isn’t on this page, write to us at [email protected] and tell us which one and why. The roadmap above is informed; it isn’t fixed. A few of the comparisons we ended up writing first were prompted by readers asking for them.

Or, if you’ve read enough, the rest of the site is back at epistles.com. Early access is open on macOS, Linux, iOS, and Android, fifteen-day trial, no card up front, three accounts on the free tier afterwards.