Spark Alternatives in 2026: Pick by Why You're Leaving

The right Spark alternative depends on what pushed you away. If it was the price of Spark's AI plans, Apple Mail and Thunderbird cost nothing. If it was mail passing through Readdle's servers, Thunderbird says it collects no personal data and Proton Mail encrypts the whole inbox. If it was the missing Linux or browser version, Thunderbird and Proton both cover that.

Spark is a good app, and plenty of people should stay. This page sorts out who those people are, then walks through four other options, what each one costs today and what you give up by moving.

What Spark does well

Spark's free plan is generous. According to Spark's pricing page, Free includes the Smart Inbox, unlimited email accounts, Smart Notifications and a calendar, at $0. The Smart Inbox, as Spark describes it, sorts new mail into personal, newsletter and notification categories and places mail from real people first.

Gatekeeper is Spark's other standout. Spark's Gatekeeper page says it screens a new sender and lets you accept or block future mail from them, down to a whole domain.

Spark runs on four platforms. Spark's download help lists Mac (macOS 13 or later), Windows (64-bit Windows 10 or later), iPhone and iPad (iOS 16.4 or later) and Android (Android 10 or later), and the pricing FAQ says a subscription bought on iOS also works on Mac, Windows and Android.

Teams get the most out of it. Spark for Teams offers shared threads, private comments inside a thread, drafts written together in real time and shared inboxes where email can be assigned. If your team answers customers out of one inbox, Spark is likely the better fit than anything else on this page, all of which are picked with individuals in mind.

The usual reasons to leave Spark

Three complaints come up most often in write-ups about switching away from Spark, and each one points to a different app.

Spark's AI now sits behind a paid quota

Spark +AI is off by default and runs on a monthly quota, per Spark's pricing page. Free users get a limited preview and can't buy more once it's used. Plus costs $10 per user a month, or $99 a year, and adds Spark +AI and 40 AI Meeting Notes a month. Pro costs $20 per user a month, or $199 a year, and adds unlimited Meeting Notes, Autopilot, Auto-Drafts and read statuses. For someone who only wanted a tidy inbox, that's a lot of plan for features they may never open.

Some of your mail passes through Spark's servers

Most of your mail stays on your device, and Spark is open about the rest. Spark's app privacy policy says recent emails are kept on its systems for four hours, Send Later emails until they're sent, and emails shared by link until the link or account is deleted. Login credentials are stored as a token. AI features may use third-party AI providers, which can keep inputs for up to 30 days for abuse monitoring, and the policy says Spark doesn't use your data to train any AI model. Whether that's acceptable is a personal call. Some people want no middle layer at all.

No Linux, no browser

Spark's download help lists Mac, Windows, iOS and Android, and nothing else. If you work on a Linux machine or need to check mail from a borrowed computer, Spark can't follow you there.

Which Spark alternative fits your reason

Apple Mail: the free choice if every device you own is Apple

Apple Mail comes with every Mac, iPhone and iPad, so there's nothing to install or pay for. On the Mac, Apple's Mail guide says Mail sorts incoming messages into Primary, Transactions, Updates and Promotions, which covers much of what Spark's Smart Inbox did.

For privacy, Apple Mail has a setting Spark doesn't match one for one. With Protect Mail Activity turned on in Mail → Settings → Privacy, Apple says your IP address is hidden from senders and remote content is downloaded privately in the background when a message arrives, rather than when you open it.

The catch is the platform. Apple Mail doesn't run on Windows or Android, so anyone who left Spark for a Windows laptop or an Android phone needs a different answer. Apple's Writing Tools in Mail rely on Apple Intelligence, which Apple's guide notes isn't available in all languages or regions.

Best for: people fully on Apple hardware who mostly used Spark for sorting and want the simplest swap.

Thunderbird: free and open source, including on Linux

Thunderbird is the answer for Linux, and a strong one everywhere else. Thunderbird's site calls it "free forever" and open source, funded by user donations, with downloads for Windows, macOS and Linux and a mobile app on Android through Google Play and F-Droid.

It handles several accounts in a unified inbox or separately, and keeps mail, calendars and contacts in one app. On privacy, the project says it doesn't collect personal data, sell ads in your inbox or train AI on your private conversations.

The gap for a Spark user is the iPhone: Thunderbird's site lists no iOS app today. Pair it with Apple Mail on the phone and your mail stays in sync anyway, because both read from your provider's server.

Best for: Linux users, Windows users who want no subscription, and anyone who prefers software with its code in the open.

Proton Mail: when privacy means changing email providers

Proton Mail is a different kind of move. Spark, Apple Mail and Thunderbird are apps that read the email account you already have; Proton is an email service with its own addresses. Proton says it uses end-to-end and zero-access encryption so it can't see your inbox on any plan, and that the company is headquartered in Switzerland.

Proton's free tier, per its pricing page, has one address and 150 messages a day. Mail Plus is $4.99 on the one-month option or $47.88 billed every 12 months, and Proton Unlimited is $12.99 on the one-month option or $119.88 every 12 months. Easy Switch, included on every plan, imports mail from Gmail, Yahoo and Outlook. Paid plans can use Proton Mail Bridge to read Proton mail in a desktop client such as Thunderbird.

Proton's download page lists apps for iPhone, Android, Mac and Windows plus a browser version, with Linux in beta. That covers both of Spark's platform gaps at once.

The cost is the address. Everyone who writes to your old Gmail or Outlook keeps writing there until you tell them otherwise.

Best for: people whose reason for leaving Spark is privacy, and who are ready to change the address they hand out.

Merlin: an assistant that reads your Gmail, not a mail app

Merlin is our app, and it doesn't replace Spark as a mail client. Merlin runs on macOS, connects to your Google accounts and works next to whatever mail app you use, Apple Mail included.

What Merlin does with email is triage and follow-through. Its Inbox Watcher reads new Gmail and, when something is urgent or important, posts a line or two in chat saying who wrote and what they need, while newsletters and promotions stay quiet. Sign-in codes arrive in chat within seconds. A Daily Digest at 8 AM covers important email and the day's calendar across every connected account. A reply you ask Merlin to write waits in chat for your changes and your approval before anything is sent.

The limits matter for someone leaving Spark:

• Mac only. There's no Windows, Android or iPhone app, and Merlin's notifications don't go to your phone.
• Gmail only. Merlin's email features need a connected Google account; you can link up to five on a paid plan. Mail on Outlook, iCloud or other providers isn't covered.
• No screening or shared inbox. Merlin can't create Gmail filters, and it has no sender screening like Gatekeeper and no shared team inbox.
• Not the privacy pick. Merlin reads your mail through Google's permission, and its routines run on Merlin's servers so they keep working while your Mac sleeps. If servers were your reason to leave Spark, Merlin doesn't solve that.

On the free tier you get two Google accounts and a monthly allowance of 5,000 credits, used up task by task. Paid plans start with Pro at $29 a month, with 20% off billed annually (a one-time lifetime plan is also offered; see Merlin's pricing), and add a Merlin email address of its own and meeting transcription.

Best for: people whose mail is in Gmail, who work on a Mac, and who were paying for Spark's AI mainly to know which emails need them.

Spark and its alternatives side by side

How to choose

• You work in a team that shares an inbox: stay on Spark, or check any replacement for shared drafts and assignment before moving.
• You're all Apple and want to stop paying: Apple Mail, with Protect Mail Activity on.
• You're on Linux or Windows and want free: Thunderbird, plus your phone's own mail app on iPhone.
• You want your provider unable to read your mail: Proton Mail, and plan time to tell people your new address.
• You live in Gmail on a Mac and mostly want to know what matters: a free mail app plus Merlin.

Leaving Spark without losing mail

Your messages don't live in Spark. Spark's storage help says the content of the emails you send and receive is stored on your email account's server, so any app you switch to sees the same mail. The month of mail Spark caches for offline reading can't be saved or moved, and doesn't need to be.

1. Clear what Spark is holding. Scheduled Send Later emails and team items are stored on Spark's servers, per the same help page. Send them, or recreate them in your new app.
2. Set up the new app with the same accounts and confirm your folders came across. If you're going back to Gmail on the web, Gmail labels are where your sorting lives.
3. Remove your data from Spark. On Mac and Windows, open Spark Settings, select the first section in the sidebar, click Remove your data and type "Remove" to confirm, as Spark's removal guide describes. Android and iOS have the same option under Settings.
4. Cancel the subscription where you bought it. The same guide says a Stripe subscription is canceled automatically when you remove your data, but App Store and Google Play subscriptions have to be canceled yourself.