Email clients
The email client market is not a features race — it's a trust race around reliable delivery. The winner is the one where deletion deletes, push actually pushes, and sending is guaranteed. Every other layer — privacy, AI, unified inbox — only has value on top of a working foundation, and it's exactly that foundation that gets shattered by updates across the category.
Three findings
Core reliability: delivery, sync, sending
The foundation that keeps collapsing across the market: deleted messages come back, actions fail to sync, emails get stuck in Outbox, and sending only works while the app is open. Users do not forgive email for breaking the basic contract — "I did something and it stuck." This is the number-one driver of churn in the entire category.
Deleted emails keep rising from the dead14
The single most widespread pain in the category: a user deletes, archives, or sorts emails into folders, and after the next sync they surface right back in the inbox — sometimes instantly, sometimes an hour later. People end up deleting the same email three to six times before giving up and switching to an app where deletion actually sticks.
Can't send emails, can't delete emails, can't move emails. Everything keeps popping back into my inbox. What's going on.
it fails at deleting emails and deleted emails keep coming back to your inbox
when emails are moved to different folders they sometimes end up back in the inbox next time it's opened
Emails take a minute to open — the client is slower than the web12
Opening a message, refreshing the list, hitting send — every action takes seconds or even minutes. Users drift back to the web interface or to Gmail itself because the third-party client is slower than the underlying service it sits on top of.
Emails load only when you open the app and you have to wait while it's doing this. I have tried everything and I can't get around this. 2 minutes wasted every time
The product (Proton mail) is good, but the app is absolutely terrible. It never refreshes, doesn't update, gets frozen, it's practically useless.
i am tired of white screens, emails cross loading, waiting for ages for the list to load or for the app to fetch new emails
An update broke the app they loved12
A recurring pattern across the category: "used it for years — the latest update killed it." A new UI hides familiar features, resets settings, breaks search and sync. Bluemail and Yahoo take the hardest hit: loyal users of five to ten years leave waves of 1-star reviews after redesigns.
fixing that which is not broken and calling it progress seems to be the wisest thing AI or anyone can seemingly come up with to only further complicate that which is simple
the layout since the update is horrible. no option to return to old layout.
This app turned from one of the best out there to borderline the worst one. the new version is bug ridden, full of ai bloatware
Emails don't send or arrive without supervision11
Messages get stuck in Outbox, "Sent" turns out to be a lie, and sending only works while the app is open. For anyone using email professionally, this destroys trust: you can't rely on a message actually having left your hands.
constantly says it's sent mail then I find out later it never sent, you MUST NOT go off the app at all otherwise emails will not send
this app keeps it in the outbox, then sends it again the next time I open the app
all my emails are failing to send unless I babysit them through the sending process
Sign-up wall: banned before you send your first email10
A pain unique to privacy-first services: when creating an account, your IP gets flagged for "abuse prevention," the captcha loops endlessly, manual approval takes 24–48 hours — and that approval requires you to send an email from the account that isn't approved yet. People leave for Proton before they've read a single message.
My account needs to be approved by me sending an email from my tuta account — but I can't send any emails without my account being approved. genius logic guys
Couldn't let me create an account. Said "Your ip address is temporarily banned" when I just opened the app.
Created an account and then it keeps saying the login credentials are incorrect...
Accounts keep dropping — constant re-authentication10
Outlook, Hotmail, and Google accounts regularly "lose credentials," forcing users to re-enter passwords across three mailboxes — often after an update or just every couple of days at random. It kills the fundamental expectation of "log in once and it works."
it keeps asking me to reauthenticate my Hotmail accounts on a regular basis. Real pain
Keeps logging out of Outlook even after several updates that claim to have addressed this issue.
It disconnects my email accounts almost every time I open the app.
Monetization and trust: paywalls, ads, bait-and-switch
Where money meets trust. Basic features — blocking, search, an extra address — get locked behind expensive subscriptions; free tiers turn out to be traps; ads take over the entire screen; and store ratings are inherited from an older free version. The gap is an honest micro-tier and transparent pricing before you commit.
"Free" turns out to be a paywall at the door11
Spike dropped its free tier and now pushes a subscription the moment you open the app; Aqua Mail and Tuta advertise "free" but let you add only one account or ask for a card upfront. Users feel bait-and-switched and write "scam" — while the store rating still reflects the old free version.
just to change to fully paid ai email client. meanwhile still retaining all the ratings from the previous version. this is a scam
No longer free even with one email account. I can't access anything because it takes me straight to a subscription payment page.
wasted half an hour to set the damn thing up and then it asked for money, if you want to sell something, do it up front
Search is either broken or locked behind a paywall8
Proton has been missing in-app search for years; Tuta's indexing takes hours and doesn't survive a restart; Bluemail and Yahoo broke search in an update. Finding last year's receipt for a warranty claim is genuinely painful. A core feature, still unresolved.
After much more than a decade it's still not possible to search your mail in the app
Indexing emails takes literal hours and is not done in the background. It is not persistent between devices.
you can no longer search for emails which is a big part of my business. it says nothing found
All-or-nothing pricing — no room for one honest inbox8
A pricing gap: a user wants one or two small things (auto-empty trash, remove signature, one extra address), but the only option is an expensive bundle with VPN, storage, and AI they don't want. A direct, repeated ask for a cheap micro-tier — "99 cents for what I actually need" — goes unheard.
You need another tier for users like me who just want auto empty trash and removal of signatures. I don't want more storage, addresses or any of the other stuff (or vpn). Maybe 99¢ would do.
I bought the app for like $5 in 2017. Now they're charging TWICE that per MONTH!!
Gatekeeper is an interesting feature but more expensive than I'd like to pay, but you guys are using a third of my screen to lead me to a subscription paywall
Full-screen ads before you can read a message8
Mainly an Aqua Mail and Yahoo problem: unskippable video ads that sometimes run pornographic or Temu banners, playing for up to two minutes between every action. A professional user can't read a work email without waiting out an ad — app deleted immediately.
worst email app ever. full screen Temu scam ads in your face for a forever 1-2 minutes between every single action you take on this app with no way to close them
when I started seeing pornographic adverts on this app I was furious. Especially because I use this app in a professional capacity.
Full screen ads that won't go away are NEVER acceptable!
Experience and positioning: privacy, AI, screen size, onboarding
The differentiation layer. Proton's and Tuta's privacy stance creates devoted users, but archive recovery and registration walls push people away. Forced AI, gamification, stretched UI on large screens, and clunky onboarding are easy ways to lose — or, conversely, to stand out through restraint and honesty.
Unified inbox — the whole reason people install the app14
The one value that earns consistent praise: all mailboxes in one place, no account-switching. Edison, Bluemail, and Canary retain users on exactly this — "one screen for Gmail, Outlook, Yahoo, and iCloud." Outlook still hasn't shipped a proper unified inbox.
Easy to use, well designed email app. Works much better than Outlook. It also has a unified inbox, which Microsoft still hasn't figured out.
love having all my mailboxes in one place and can open only one at a time if I want
I have tried many email apps. This one stand out. It was easy to use. It even got all the gmail folder. I combined with other emails. View all emails in one app.
Notifications go silent — you only know mail arrived by opening the app13
Push notifications randomly stop working, arrive hours late, or never come at all. The most basic promise of an email client — "tell me when something arrives" — breaks down, and users miss things that matter. For apps that run without Google services (Tuta, Proton) this is a structural weakness.
I am not getting new email notifications. I have to open the app each time to check for new emails. I think it's a basic feature.
I am not getting notifications and have tried everything but for me to see new emails I have to open the app
push notifications will spontaneously stop working and the only way to get them back is to reinstall the app
Privacy — the one thing people endure everything else for12
Proton's and Tuta's clean, surveillance-free approach creates genuine fans: no ads, no tracking, "de-Googling." It's the only axis on which users forgive weak search and slow sync. A strong brand narrative that competitors can't easily copy.
Proton provides everything I need in an email client, without all the invasive bits
No ads, no unnecessary AI, no unwanted noise.
I have come to "de-g00gle" recently to protect my privacy and not have my emails used for training AI, and Tuta Mail fits the bill perfectly
Forced AI: the button won't go away and it hijacks replies11
A permanent AI button stuck in the toolbar, an assistant that pops up every time you reply, and in some cases an app that sends messages with its own signature without asking. A large and vocal group of users explicitly writes "we don't want AI, give us a working email app" — and leaves over a feature they never asked for.
the app sent an email with a Canary signature automatically, without my permission. This is by far the worst email app I’ve ever used.
Why is there now an AI button that I can't get rid of in the bottom menu while reading email? WE DON'T WANT AI.
I don't need AI, just a working email client!
The spam filter doesn't learn — you block it, it comes back10
Marking something as spam doesn't stick: the same sender lands in the inbox again and again, sometimes dozens of times. Aqua loses users to eM Client specifically over this; Bluemail stopped filtering altogether after an update. A filter that actually remembers is a real, unaddressed need.
Aquamail doesn't save your spam/junk rules so what ever you mark as spam/junk will not get rejected next time so you'll have to do it manually everytime
it no longer filters emails for spam, and I can't block any emails, domains, etc. My inbox is now flooded with garbage
I keep marking emails as spam, but I still continue getting the same types of messages over and over
Account recovery equals losing your emails forever7
The dark side of end-to-end encryption: forget or reset your password and old emails are encrypted and gone for good. Recovery methods (old device, key file) are not built for ordinary people. The real fear of losing years of email keeps many people from switching to a private service.
now my old emails are encrypted and because the recovery methods are "use a prior device or remember your old password or upload a recovery key/file" i now cannot access my old emails. these are not regular person methods of recovery.
Useless Password Recovery That DOESN'T WORK
My concern about Tuta is that account recovery depends mainly on a recovery code, which is secure but risky if it is lost.
Two more findings — with the breakdown and review quotes.
7 opportunities
Ideas users ask for themselves — each backed by proven demand.
10 apps
The fastest-growing players — Proton and Tuta — win on a privacy and "de-Googling" narrative, but stumble on silent push notifications, slow sync, registration walls, and irreversible encryption of archived mail. The universal aggregators (Spark, Edison, Bluemail, Canary) hold users with a unified inbox but monetize basics (sender blocking, search) and routinely alienate loyal users with redesigns and forced AI. Aqua, Spike, and Yahoo push people away with full-screen ads, bait-and-switch paywalls, and gamification — leaving a clear opening for a client that is honest, fast, and predictable.
Spark MailReclaim your time and focus with Spark — the AI-powered email app loved by millions.
Edison MailHave you ever looked at your overflowing inbox and groaned?
Proton MailProton Mail's all-new encrypted email app protects your communications and has everything you need to easily manage your inbox.
Canary MailCanary is the AI email app made to help you do more with your conversations.
BluemailBlue Mail is a free, secure, beautifully designed, universal email app, featuring smart and elegant user experience and capable of managing an unlimited number of mail accounts from various providers.myMailHave you ever looked at your overflowing inbox and groaned?
Spike EmailSpike is the AI-powered email client that upgrades your inbox.
Aqua MailFAST AND SECURE email app for android
Looking for a reliable email app for android to manage all your emails from one place?
Tuta MailPROTECT YOUR PRIVACY WITH TUTA MAIL FOR FREE: SECURE, PRIVATE AND ENCRYPTED EMAIL
Take control of your communications with Tuta Mail - the world's most secure email service trusted by over 10 million users worldwide.
Yahoo MailYAHOO MAIL: THE SMART INBOX DESIGNED TO SIMPLIFY YOUR LIFE
Yahoo Mail is the ultimate smart inbox and advanced email organizer, built to simplify your life and get more done in less time.