Best Mailspring Alternatives in 2026

If you are looking for the best Mailspring alternatives in 2026, the honest starting point is that Mailspring is not dead. Its maintainers say active development resumed in 2025, and the current release line ships accessibility, vCard and calendar work (checked on getmailspring.com, August 2026). What sends people looking is usually one of three things: a slow patch cadence over the years, Pro features locked behind a subscription, or questions about how the sync engine handles their mail.

This page compares maintained clients you can switch to, and it is precise about which parts of Mailspring are actually open source, because that is the reason a lot of people chose it. We list eight options across Windows, macOS and Linux, say plainly where each one wins, and name the one we build.

The short answer: our top picks#

For most people leaving Mailspring on Windows or a Mac, AI Emaily is our top pick. It is an AI-native client that triages your inbox and drafts replies in your voice, and it asks for your approval before it sends anything. We build it, so treat this as the disclosed recommendation it is.

If your reason for using Mailspring was that it is free, open source and runs on Linux, AI Emaily is not your answer: there is no Linux build. In that case Thunderbird is the honest top pick, because it is free, open source, and native on Windows, macOS and Linux.

How we compared#

We did not run a twelve-app bake-off, and we are not going to claim one. We compared these clients on documented capabilities — the things that actually decide whether a client replaces Mailspring for you.

• Platforms — does it cover the desktop you are on, and Linux specifically?
• Open source — is the code readable under a real open license, or closed?
• Sync model — does your mail move through a vendor's servers, or stay between your machine and your provider?
• AI and automation — does it just display mail, or does it triage, draft and act?
• Packaging — free tier, paid subscription, one-time license, or a trial?

Which parts of Mailspring are actually open source?#

Here is the precise answer, because it is the thing most pages get vague about. Mailspring's Electron user interface and its C++ sync engine are both open source under the GPL-3.0 license, per the LICENSE file and the README in the Foundry376/Mailspring repository (checked August 2026). The README also states the sync engine runs locally on your computer and that Mailspring does not send your email credentials to the cloud.

Mailspring Pro is the paid layer on top: read receipts, link tracking, send-later, follow-up reminders, templates, contact enrichment and mailbox insights, unlocked by a monthly subscription and a Mailspring ID. Some of those features reach the vendor's servers to work. So the client and its sync are genuinely open and local, while a subset of the paid conveniences are the part that is not purely local. If a marketing summary you see calls the license something other than GPL-3.0, the LICENSE file in the repository is the source that settles it.

Mailspring alternatives at a glance#

Here are the eight, ranked. Verify the current tier and privacy terms on each vendor's own page before you commit — packaging in this category moves often, and several of these facts are dated below for that reason.

1. AI Emaily — the inbox worked, not just displayed#

We build AI Emaily, so read this as the disclosed pick it is. Where Mailspring shows you a fast, tidy inbox and leaves the work to you, AI Emaily is built to do the work: an agent reads incoming mail, sorts it, and drafts replies in your voice, then waits for your approval.

The voice comes from a Personal Context brain you set up and per-client profiles you control — not from scraping your past sent mail. You choose how much autonomy it has: Manual, Copilot (it drafts, you approve every send), or a gated Autopilot. Every action is undoable and written to an audit log, so nothing happens to your mailbox that you cannot see and reverse. It connects Gmail, Outlook and standard IMAP, including iCloud, Fastmail, Proton, Yahoo and Zoho, and it does not train models on your mail.

Now the honest limits, because they matter for a Mailspring switch. There is no Linux build. AI Emaily runs on the web, a downloadable macOS app (Apple Silicon only, not the Mac App Store), a Windows installer, a native iOS app, and an Android PWA. The desktop app is a real downloadable application built as an Electron shell around the web client, so it will not match a native client on memory footprint or a full local offline archive. And there is no permanent free tier: it is a 7-day free trial on the paid plans, card required, and $0 if you cancel before day 7. If free-forever is the requirement, pick Thunderbird below.

2. Thunderbird — the free, open-source pick that runs on Linux#

Thunderbird is the closest like-for-like replacement for what drew people to Mailspring: a free, open-source desktop client under the Mozilla Public License, native on Windows, macOS and Linux, and now with an Android app too. It is maintained by the Thunderbird project and funded by donations, not a subscription.

It is the honest top pick for anyone whose real requirement is the license and the platform reach — especially Linux users, who AI Emaily cannot serve. The interface is more utilitarian than Mailspring's, but recent releases have modernised it, and add-ons cover a lot of ground. An AI feature called Assist is in development inside Thunderbird Pro, but it is beta rather than shipping in the free desktop client as of August 2026 — so treat Thunderbird as a strong client you attach AI to, not an AI client. If you want free, open, local and Linux-friendly, stop here.

3. eM Client — the polished paid desktop client#

eM Client is the move if you liked Mailspring's modern feel but want something more complete and more actively supported. It runs on Windows and macOS as a full desktop PIM — mail, calendar, contacts, tasks and notes — with iOS and Android apps as lighter companions.

It carries a free tier for personal, non-commercial use with a small cap on connected accounts, and a paid Pro license that lifts the cap and enables commercial use; Pro has historically been sold as a one-time lifetime purchase as well as a subscription. It is not open source, and it includes a built-in AI writing assistant rather than an agent that acts on your inbox. Verify the current free-tier limits and license options on emclient.com, because eM Client has adjusted them across versions. For a reader who wants a refined, do-everything desktop client without the AI-agent layer, this is the strongest pick on the list.

4. Mailbird — Windows-first, now on Mac#

Mailbird spent years as a Windows-first client known for a clean unified inbox and a wall of app integrations. Since October 2024 it also ships a macOS build, and as of 2026 one license covers both platforms, so a Windows-and-Mac household is not buying twice.

It is paid software with a free trial rather than a permanent free tier, and packaging has shifted over time between subscription and lifetime options — check getmailbird.com for the current split before you buy. It is closed source, and its AI is a writing assistant, not an agent. There is no Linux build and no mobile app, so it is the wrong answer if either matters. But if you are a Windows or Mac user who liked Mailspring's tidy inbox and wants deeper third-party integrations plus privacy-hub features like pixel-tracker blocking, Mailbird is the natural upgrade.

5. Spark Mail — cross-platform, with a team option#

Spark, from Readdle, is a cross-platform client across Windows, macOS, iOS and Android with a smart inbox that groups and prioritises mail, plus an AI compose feature. It has a free tier and a paid Premium tier, and it adds shared drafts and a light shared-inbox layer for teams — something Mailspring never offered.

The thing to check before you move a mailbox is the sync model. Spark uses its own infrastructure to power some features, which is a different shape from a client that talks only to your provider. Readdle publishes a privacy page and a privacy-focused setup, and it is worth reading before you connect an account. If you want a modern, good-looking client that works everywhere and gives you a taste of team collaboration, Spark is a solid pick; if a fully local sync path is a hard requirement, weigh it against Thunderbird.

6. Canary Mail — AI plus encryption#

Canary Mail leans into two things Mailspring does not: a built-in AI assistant and end-to-end encryption. It runs on macOS, Windows, iOS and Android, and its packaging is a Free tier plus Growth and Pro+ paid tiers (verified against its pricing page in July 2026 — confirm current terms before buying).

The AI can summarise threads, draft replies and help you triage, and the encryption support appeals to people who want privacy features in the client itself rather than bolted on. It is closed source. For a reader who wanted more from Mailspring than a tidy inbox — specifically AI help and encryption — Canary covers both in one cross-platform app. As always, the exact tier limits move, so read the current plan page before you decide.

7. Shortwave — AI-native, but Gmail only#

Shortwave is an AI-native client built by former Google engineers, with strong semantic search, AI summaries and AI-assisted triage. It runs on the web, macOS, Windows, iOS and Android. The catch for a Mailspring refugee is the scope: Shortwave is built for Gmail and Google Workspace, so it is not a general IMAP client the way Mailspring is.

Packaging is the other thing to verify. Older reviews describe a free plan, but a check of the vendor's pricing page in July 2026 showed paid tiers with a trial and no free plan — so confirm current terms on shortwave.com rather than trusting a review. If you live entirely in Gmail and want AI baked into the client, Shortwave is one of the best in the category. If you connect Outlook or arbitrary IMAP accounts, it is the wrong tool, and AI Emaily or Thunderbird will fit better.

8. Apple Mail — free and native, if you are all-Apple#

If you are entirely on Apple hardware, the built-in Apple Mail is the zero-cost, fully native option Mailspring's Electron app can never be. It runs on macOS and iOS/iPadOS, it is free, and recent versions add Apple Intelligence features — message summaries, priority messages and smart replies — on supported devices.

There is no Windows, Linux or Android version, and it is closed source, so it only makes sense if every device you use is made by Apple. It is not an agent: the AI is summarisation and suggestions, not triage-and-act. But for an Apple-only user who wanted Mailspring mainly for a clean, free client and does not need cross-platform reach, Apple Mail is the simplest answer, and it costs nothing.

Is Mailspring still maintained in 2026?#

Yes, as of August 2026. After a stretch of slow releases that pushed a lot of users to look elsewhere, Mailspring's maintainers state that active development resumed in 2025, and the current release line added accessibility improvements, vCard support and calendar updates. The Foundry376/Mailspring repository shows ongoing commit activity.

So "is Mailspring dead" is the wrong question — it is not. The better questions are whether the patch cadence is fast enough for you, whether you are comfortable with Pro sitting behind a subscription, and whether you want AI inside the client. If the answers are yes, yes and no, you may not need to switch at all. If any answer is no, the eight options above cover the exits. Check getmailspring.com for the current release date before you decide.

How to choose for your situation#

Our recommendation, stated plainly: if you are on Windows or a Mac and the thing you actually want is less time in your inbox rather than a nicer place to spend it, try AI Emaily. The agent triages, drafts in your voice and asks before it sends. We build it. If your requirement is free, open and Linux, we are not your tool, and Thunderbird is.

• You want free, open source, and Linux: Thunderbird. Nothing else on this list matches all three.
• You want the inbox triaged and drafted for you, and you are on Windows or Mac: AI Emaily — with the caveats that it is paid after a 7-day trial and has no Linux build.
• You want a polished, complete desktop client without an AI agent: eM Client, or Mailbird if you are on Windows and Mac and love integrations.
• You live entirely in Gmail and want AI in the client: Shortwave.
• You want AI and encryption in one cross-platform app: Canary Mail.
• You are all-Apple and want free and native: Apple Mail.
• You want to keep Mailspring but were worried it was abandoned: it is being maintained again — re-check the changelog first.