The right replacement depends on what you want your inbox to do differently. If you work alone and want speed or AI help, pick a smart email app. If several people answer the same mail, pick a shared team inbox, and if privacy matters most, move your mail to a private host. Here are nine options, unranked.
Your inbox is where the deals, the follow-ups and the awkward chasers all live. Polymail built its pitch on that, so leaving it isn't a small decision: you're changing the place you spend most of your working day. Below are nine email apps and inbox tools in no particular order, starting with the full list and then how they differ.
Nine inbox tools from A to Z
Alphabetical, not ranked. Each line reflects how the vendor describes its own product.
Canary Mail
Best for: People juggling several addresses who want all their accounts in one inbox, with AI and a calendar built in, according to the vendor.
Fastmail
Best for: Individuals and small businesses wanting their own fast, private email hosting and calendar, rather than an app sitting on top of another provider.
Mailbird
Best for: Desktop users on Windows or Mac pulling Gmail, Outlook, Exchange and IMAP accounts into a single workspace; the vendor names a free plan.
Mimestream
Best for: Mac owners who run their mail through Gmail and want a native macOS app made for it, rather than a browser tab.
Missive
Best for: Small teams that share email: the vendor says you can see who's doing what and talk behind the scenes without changing how you work.
Shortwave
Best for: Anyone happy to hand inbox chores to AI; the vendor says its agent organises, writes, searches and schedules from a prompt, and names a free plan.
Spark
Best for: Busy professionals who want important mail pulled to the top and the rest cleared quickly, which is how the vendor frames its app.
Superhuman
Best for: Executives and heavy email users wanting AI help in the inbox and beyond; the vendor now pitches itself as a suite for everywhere you work.
Tuta
Best for: Privacy-minded users and businesses wanting encrypted, ad-free email; the vendor highlights quantum-resistant encryption and names a free plan.
Email apps compared in one table
| Tool | Kind of tool | Good for |
|---|---|---|
| Canary Mail | Multi-account email app | Several accounts and a calendar in one inbox |
| Fastmail | Email hosting | Private email and calendar for you or your business |
| Mailbird | Desktop email client | Gmail, Outlook and IMAP accounts on Windows or Mac |
| Mimestream | Native Mac Gmail client | Gmail users who work on a Mac |
| Missive | Shared team inbox | Teams handling customer email together |
| Shortwave | AI email assistant | Sorting, writing and searching mail by prompt |
| Spark | Focused email app | Seeing what matters first and clearing the rest |
| Superhuman | AI productivity suite | Heavy email users who want AI across their work |
| Tuta | Encrypted email | Private, ad-free mail with strong encryption |
Three kinds of inbox tool
These tools aren't all doing the same job, and that's the first thing to sort out. Some sit on top of the email account you already have. Some replace your mail provider altogether. And one is built for a team rather than a person.
Apps on top of your existing accounts
Canary Mail, Mailbird and Spark pull your existing accounts into one place, so you keep your address and change only the window you read it in. Mimestream goes narrower: it's a native Mac app for Gmail only, which is great if that's your setup and a dead end if it isn't.
AI-first inboxes
Shortwave and Superhuman both put AI at the centre. The first leans on prompts to sort, write and search your mail, while the second now talks about AI help across all your work, not only email. If you write a lot of replies, these are the ones to try first.
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Shared inboxes and private mail hosts
Missive is built for teams that answer the same mailbox together, with internal chat around each thread. Fastmail and Tuta are different again: they're mail providers, not apps, so moving to them means changing where your email lives. The first leads with speed and privacy for individuals and businesses, and the second puts encryption at the heart of its pitch.
What the switch does to your daily routine
Polymail's own page describes it as a control centre for getting work done, with tracking, follow-ups and scheduling inside email for founders and operators. That's the thing to test in any replacement: how it changes your daily inbox routine, and which mail accounts and devices it supports.
If you rely on open tracking, follow-up reminders or send-later, check each shortlisted tool's feature list for those exact jobs before you move. Then check the devices. A tool that's lovely on a Mac is no help if half your day happens on an Android phone, and a desktop client won't follow you to a borrowed laptop. Tools in this category split by who they're built for and how much you set up yourself, so run the same week of real email through each before you decide.
My advice for founders and operators changing email apps
Start with the problem, not the shiny feature. If you're missing follow-ups, you need reminders and a clear view of what's waiting on someone else. If you're drowning in volume, you need sorting and faster replies, which is where the AI-first tools earn their place. If a colleague keeps answering the same customer as you, a shared inbox will fix more than any personal app.
Keep the rest of your email setup in mind as you choose. Your signature, your templates and any automated sequences all need a home after the move; my guides to email signature software and email automation tools cover both sides. And don't change provider and app in the same week unless you have to. One change at a time makes it far easier to see what's working.
Moving your mail without losing a thread
- List every account and device you read email on today.
- Note the follow-ups, reminders and scheduled emails you have waiting, and finish or copy them before you switch.
- Export your templates and signature so you can rebuild them in the new tool.
- Connect one account first and live with it for a few days before adding the rest.
- Check that sent mail, labels and folders look right on your phone as well as your computer.
- Only then remove the old app and its access to your accounts.
Do you make email apps or inbox tools? Tool makers can ask to be considered for a featured place on this list.
Want your tool on this list? Featured spots and reviews here are paid partnerships. Here's how to partner with me.
Frequently asked questions
What's the difference between an email app and an email provider?
An email app is the window you read mail in, and it works with accounts you already have. A provider hosts your mail and your address, so changing provider means moving where the mail lives.
Can I keep my email address if I change email apps?
Yes. An email app connects to your existing account, so your address stays the same. You'd only need a new address, or to move a custom domain, if you change provider.
Is email tracking allowed?
Rules on tracking pixels and privacy vary by country. Check the guidance from your data protection regulator, and tell recipients in your privacy notice if you track opens.
Do AI email assistants read my messages?
To sort or draft replies, they need access to your mail. Read each vendor's privacy and security pages to see how your data is processed and stored before you connect an account.
What's a shared inbox?
It's one mailbox, such as a support or sales address, that several people answer together. Good shared inboxes show who's handling each thread so two people don't reply to the same customer.
How long does it take to switch email apps?
Connecting an account takes minutes. Rebuilding your templates, signatures, filters and habits takes longer, so plan for a week or two of overlap.
