Port 993, any provider, up to 120 mailboxes
IMAP Email Client: IMAP Mail Client and Email Software in One Inbox
If it speaks IMAP, it connects. Gmail, Yahoo, iCloud, AOL, Zoho, Fastmail and any company domain arrive on one board, in a browser tab, with a model reading each message and tagging it before you get there.
Nothing installed · Same session on every machine · Archiving synced back
The short answer
An IMAP email client is any program that reads your mail over the Internet Message Access Protocol on port 993, leaving messages on the provider server so every device sees the same mailbox. Almost every client is one: Thunderbird, eM Client, Apple Mail, Mailbird and Outlook all speak IMAP, and picking between them on protocol support alone is pointless because they all support it. The real difference shows up once you connect the fifth mailbox. Most clients merge accounts into one list and stop there, which turns five piles into one larger pile. Inboxes is a web based IMAP client: connect up to 120 mailboxes with an app password, read them on one board in a browser tab, and have a model assign each message a category (Important, Newsletter, Notification, Spam, or Other), plus a spam verdict, before you open it. Archive and junk decisions push back to the IMAP server, so your phone shows the same state.
Last updated August 2026
What the protocol does and does not decide
IMAP support is table stakes, so it is a bad way to choose a client
People search for an IMAP email client because IMAP is the word their provider used. It is worth two minutes to know what the protocol actually guarantees, because it rules out far less than it sounds like it does.
IMAP means the server keeps your mail. The client shows you what is on the server and writes changes back. Read a message on a laptop and it is read on your phone. Move it to a folder and the folder moves everywhere. This is the whole reason IMAP replaced POP3 for normal use, and it is why a client can be swapped out without losing anything: the mail was never in the client.
IMAP allows many clients on one mailbox at once. This is written into the protocol design, and it is why you can have a phone, a laptop and a web client all connected to the same address without any of them fighting. It also means adding a new client is a low risk thing to try. Nothing is migrated and nothing is removed.
Port 993 with TLS is the modern default. Port 143 is the older plaintext port, sometimes upgraded through STARTTLS. Every provider worth connecting to offers 993, and a setup guide that tells you to use 143 unencrypted is out of date rather than offering you a choice.
What IMAP does not do is organize anything. The protocol moves messages and folder state. It has no opinion about what a message is or whether it matters. Every bit of triage you have ever done, and every rule you have ever written, sits above the protocol in the client. So when someone with eight mailboxes asks for the best IMAP client, protocol support answers none of the actual question.
And IMAP is now where the Microsoft exception lives. For a decade, IMAP plus a password worked everywhere. That is no longer true. Microsoft finished retiring basic authentication for Exchange Online in April 2026, and Microsoft states it will fully remove basic authentication from Outlook.com as well and rely only on OAuth. Google, Apple, Yahoo and the independents still issue app passwords. Microsoft is the one you have to check first, and the section on limits below is blunt about what that means for us.
Eight IMAP clients, compared
Every one of these speaks IMAP, so compare them on what happens next
The columns that separate these are where the client runs, whether it merges accounts into one list rather than stacking folder trees, and whether anything sorts the merged list for you. Only the last column is close to empty.
Swipe to see all columns →
| IMAP client | Where it runs | Accounts merged into one list | Sorts the merged list | Cost |
|---|---|---|---|---|
| Inboxes | Browser tab, any operating system | Yes, 5 to 120 IMAP accounts by plan | Yes, AI category and spam verdict per message | $29 a month flat |
| Thunderbird 153 | Desktop, Windows, macOS, Linux | Yes, Unified Folders | No, manual rules only | No license fee, open source |
| eM Client | Desktop, Windows and macOS | Yes, real unified inbox | No, manual rules only | Free tier 2 accounts, personal use only; Personal 29.95 EUR a year |
| Mailbird | Desktop, Windows and macOS | Yes, unified inbox on paid | No, manual rules only | Free tier 1 account; 4.03 EUR a user a month billed yearly |
| Apple Mail | Desktop and mobile, Apple devices only | Yes, All Inboxes | Partly, Mail Categories on recent versions | Included with the device |
| Spark | Desktop and mobile, no Linux | Yes, unlimited accounts on the free tier | Partly, a priority inbox | Free tier; Plus 8.25 EUR a user a month billed yearly |
| Canary Mail | Desktop and mobile, 2 devices on the free tier | Yes, unified inbox | Partly, AI features on paid | Free tier; Growth $3 a month billed yearly |
| Outlook | Desktop, web and mobile | No, one account at a time in the main view | Partly, a focused inbox | Included with Microsoft 365, or ad supported |
Read the last two columns together and the field splits cleanly. Merging accounts is solved almost everywhere and has been for years, so it is not worth paying for on its own. Sorting the merged result is solved almost nowhere, because it needs something reading the messages rather than matching a rule you wrote. Prices verified August 2026. The longer nine app breakdown, including where we recommend something other than ourselves, is in the roundup of the best apps for multiple email accounts.
The case for running IMAP from a server
Six things a web based IMAP client does that a desktop one cannot
The IMAP connection has to be made from somewhere. Desktop clients make it from your machine, which is why they work on a plane and why the setup only exists on that machine. Making it from a server trades one of those for the other.
The setup exists once
Connect eight mailboxes on a Tuesday and they are connected on every machine you sign into. A desktop client that holds eight accounts holds them on that computer, and the second computer is an afternoon of app passwords all over again.
It runs on whatever you own
Windows, macOS, a Linux box, a Chromebook, a borrowed machine in a hotel. Most desktop clients skip Linux, several skip Windows, and ChromeOS cannot run any of them without turning on a container first.
The mailbox is never on the laptop
A desktop client keeps years of mail in a local profile, which is exactly what you do not want on a machine that gets lost. Nothing is cached to disk here, so a stolen laptop is a password reset rather than a disclosure.
Search runs server side
Searching across eight mailboxes at once is work, and on a desktop client it is your laptop doing it against a local index that has to stay built. Here it happens away from your machine, so a cheap one performs the same as a fast one.
Sorting happens on arrival, not on open
A server side client is already connected when mail lands, so each message is read and categorized before you look. A desktop client only sees a message once you open the program, which is why its rules feel like a queue you process.
Nothing to update
When a provider changes an authentication requirement, and 2026 has been a year of that, a hosted client is updated centrally. A desktop client waits for a release, and an unmaintained one quietly stops connecting.
Connecting a mailbox
Four steps from an IMAP host name to a sorted board
Nothing is installed and nothing is migrated. IMAP leaves your mail where it is, so connecting a mailbox here changes nothing about how it behaves anywhere else.
// 01
Generate an app password
With two step verification on, Gmail, Yahoo, AOL and iCloud all issue a scoped credential instead of accepting your account password over IMAP. Each takes about a minute in account security settings, and this is where most first setups stall.
// 02
Add the address
Common providers are detected, so the IMAP host and port 993 fill themselves in and you paste the credential. A company domain takes one extra field, usually mail.yourdomain.com, which your host publishes in the control panel.
// 03
Repeat, and everything merges
Each mailbox becomes part of one time ordered stream, tagged with the account it arrived on. Threads stay intact, and search runs across every connected account at once rather than one at a time.
// 04
AI sorts before you look
A model reads each message and assigns it a category of Important, Newsletter, Notification, Spam, or Other. Archive and junk decisions push back over IMAP, so your phone and the provider webmail show the same state.
Quick reference
IMAP server settings for the providers most US mailboxes sit on
Every one of these is port 993 with SSL. What varies is the host name and whether the provider will accept a password at all, which in 2026 is the part that actually decides your options.
Swipe to see all columns →
| Provider | IMAP server | Port | Credential a third party client needs |
|---|---|---|---|
| Gmail and Google Workspace | imap.gmail.com | 993, SSL | App password, with 2 step verification on |
| Yahoo Mail | imap.mail.yahoo.com | 993, SSL | App password, required |
| AOL Mail | imap.aol.com | 993, SSL | App password, required |
| iCloud Mail | imap.mail.me.com | 993, SSL | App specific password, required |
| Zoho Mail | imap.zoho.com | 993, SSL | Account password, or an app specific password with 2FA on |
| Fastmail | imap.fastmail.com | 993, SSL | App password, required |
| Your own domain, typical host | mail.yourdomain.com | 993, SSL | The mailbox password from your control panel |
| Outlook.com and Hotmail | outlook.office365.com | 993, SSL | OAuth. Microsoft says it will fully remove basic authentication |
| Microsoft 365 work or school | outlook.office365.com | 993, SSL | OAuth only. Basic authentication retired April 2026 |
| Proton Mail | 127.0.0.1, through Proton Bridge | 1143, local | Bridge credential, and Bridge needs a paid plan |
Settings checked against provider documentation in August 2026. ISP mailboxes from Comcast, AT&T, Cox and similar do offer IMAP but change host names more often than the big providers, so read the current support page rather than a settings list you found. The full walkthrough, including where each app password is generated and what to do when a connection is refused, is in the guide to IMAP settings for Gmail, Outlook, Yahoo and iCloud.
Who this pays off for
Where a hosted IMAP client earns its price
One or two mailboxes need none of this, and Thunderbird costs nothing. These are the situations where merging accounts stops being the problem and the volume itself becomes the problem.
Consultants and agencies
A personal address, a company domain, a billing alias and one mailbox per client engagement. They have to stay separate for the client and arrive interleaved for you, and that is exactly what IMAP plus one board gives you.
Anyone running a company domain
Mailboxes on a host that gives you cPanel and IMAP but no decent webmail. The protocol is fine, the interface is the problem, and swapping the interface is the one change IMAP makes genuinely cheap.
Bookkeepers and accountants
Receipts, invoices and bank notices land across several addresses and get looked for again months later. Receipts and payment confirmations land in Notification with a summary and tags attached on arrival, which beats searching four mailboxes at quarter end.
People who left a desktop client behind
A working Thunderbird profile on a machine you no longer use daily. Because IMAP left every message on the server, nothing has to be exported, and connecting somewhere else costs an app password rather than a migration.
Linux and ChromeOS users
Most polished desktop clients ship Windows and macOS builds and stop. Thunderbird is the honest recommendation on Linux and we say so, but a browser tab is the only route that treats every operating system the same.
Ecommerce sellers and support desks
Orders on one address, supplier mail on another, marketplace notifications on a third. The order that needs answering today is buried under notifications that never do, and no IMAP folder rule has ever fixed that.
Where we lose
Four limits to check before you switch anything
The first one rules us out for some people entirely, so it goes first rather than last.
We authenticate with a username and password, not OAuth, so Microsoft mailboxes are a problem. Microsoft finished retiring basic authentication for Exchange Online in April 2026, which means a managed Microsoft 365 work or school mailbox will not connect to us. Microsoft has also stated it will fully remove basic authentication from Outlook.com and rely only on OAuth, so personal Outlook.com and Hotmail addresses should be treated as at risk rather than safe. If your main mailbox is a Microsoft one, Outlook itself or Thunderbird are the honest answers and we would rather you knew that now. Gmail, Yahoo, AOL, iCloud, Zoho, Fastmail and own domain mailboxes all still issue app passwords and connect normally.
There is no offline mode. The IMAP connection is made from a server, which is what makes the setup portable and keeps your mail off the laptop, and it is also why closing the lid on a plane leaves you with nothing. A desktop IMAP client keeps a local archive and reconciles later. If you work for hours without a connection on a regular basis, that is a real reason to stay on Thunderbird or eM Client.
No calendar, no contacts, no tasks. IMAP is a mail protocol and this is a mail client. eM Client and Outlook are full suites with CalDAV and CardDAV alongside. If the goal is one window holding your whole week, the comparison is not really with us.
There is no permanent no cost tier. Plans start at $29 a month flat, with 5 mailboxes on the entry plan and up to 120 on the largest. Thunderbird has no license fee at all, eM Client covers two accounts at no cost for personal use, and Spark covers unlimited accounts on its free tier. Every one of those will merge your IMAP accounts into one list. The case for paying starts when the merged list is itself the thing you cannot get through.
FAQ
Questions people ask about IMAP email clients
What is an IMAP email client?
An IMAP email client is a program that reads your mail over the Internet Message Access Protocol, leaving the messages on the provider server rather than downloading and removing them. Because the server stays the source of truth, the same mailbox looks identical in every client you connect, and a message you archive on a laptop is archived on your phone.
What is the best IMAP email client?
It depends on how many mailboxes you have. For one or two accounts on a desktop, Thunderbird and eM Client both do the job and Thunderbird has no license fee. Once you are past four or five accounts across different providers, the useful question stops being which client merges them and becomes which one sorts what arrives.
Is Gmail an IMAP client?
No. Gmail is a mail provider with a web interface, and it exposes IMAP so other clients can read it. Gmail itself cannot connect to an outside IMAP server. It could pull outside mail over POP, but Google is closing that setting to new users after early 2026, with existing users supported into January 2027.
What is the difference between IMAP and POP3?
IMAP keeps mail on the server and syncs state both ways, so reads, moves and deletions match across every device. POP3 downloads copies to one machine and, in its default setup, removes them from the server. IMAP is the right choice for anyone who reads the same mailbox on more than one device, which is nearly everyone.
What port does IMAP use?
Port 993 with implicit TLS is the standard, and it is what essentially every provider expects today. Port 143 is the older plaintext port, sometimes upgraded with STARTTLS. If a setup guide tells you to use 143 without encryption, treat that as a mistake rather than an option.
Do I need an app password for IMAP?
With Gmail, Yahoo, AOL and iCloud, yes. Once two step verification is on, those providers stop accepting your normal account password over IMAP and issue a scoped credential instead. It takes about a minute in account security settings, and a rejected password at setup is almost always this and not a typo.
Is there a web based IMAP client?
Yes. A web based IMAP client runs the protocol connection on a server and shows you the result in a browser tab, so nothing is installed and the same session follows you between machines. That is what Inboxes is. The trade is that it needs a connection, where a desktop client keeps a local archive.
Can Outlook connect over IMAP?
Outlook the program still speaks IMAP, but Microsoft mailboxes are now the exception on the other side. Microsoft finished retiring basic authentication for Exchange Online in April 2026, and says it will fully remove basic authentication from Outlook.com too and rely only on OAuth. Third party clients that authenticate with a password are affected.
Is IMAP secure?
Over port 993 with TLS, the connection itself is encrypted end to end between client and server, so nothing on the network can read it. What IMAP does not do is encrypt the message at rest on the provider server. If that matters for your work, the protocol is not the layer that solves it.
How do I find my IMAP settings?
Most providers publish them on a support page, and the pattern is predictable: imap.provider.com on port 993 with SSL. Gmail is imap.gmail.com, Yahoo is imap.mail.yahoo.com, iCloud is imap.mail.me.com. For a company domain, ask whoever runs the mail, or check your hosting control panel under email accounts.
Can I use IMAP with multiple accounts?
Yes, and that is the protocol strongest argument. IMAP allows several clients on one mailbox at once, and nothing stops one client holding many mailboxes. Whether those accounts appear as one merged list or as separate folder trees is a choice each client makes, and it varies more than people expect.
Does an IMAP client work offline?
A desktop IMAP client does, because it keeps a local copy and reconciles when the connection returns. A browser based one generally does not, since the connection to the mail server is made from a server rather than from your machine. If you regularly work for hours with no signal, that difference decides the choice.
Related
Keep reading
If it speaks IMAP, it belongs on one board
Connect every mailbox you own with an app password and let a model tag each message before you read it. Nothing installed, nothing migrated, and your mail stays on the server where it already is.