Unified inbox apps for Gmail, compared
Last reviewed
Disclosure: Postbox — this website — is one of the six options below. It is listed last and its limitations are stated in the same table as everyone else’s. Nothing here is sponsored and there are no affiliate links.
The short verdict
- Choose Thunderbird if you want the most capable option at no cost, have non-Gmail accounts, or need offline access. It is free and open source.
- Choose eM Client if you are coming from the discontinued Postbox desktop client and want your accounts and settings carried across.
- Choose Mailbird if you want a polished paid Windows or Mac client across mixed providers.
- Choose Shift if what you want is each account in its own workspace rather than one merged list. Note it has repositioned as a customisable browser rather than an email tool specifically.
- Stay with Gmail’s account switcher if you have two or three accounts and mostly read them. It costs nothing and there is nothing to install.
- Choose Postbox if every account is Gmail, you reply from several of them daily, you move between machines, and you do not need offline access.
The comparison
| Option | Pricing model | Runs as | Providers | Combined list | Offline |
|---|---|---|---|---|---|
| Thunderbird | Free, open source | Desktop | Any IMAP or POP | Yes | Yes |
| eM Client | Free tier, paid licence | Desktop | Any IMAP or POP | Yes | Yes |
| Mailbird | Paid licence | Desktop | Any IMAP or POP | Yes | Yes |
| Shift | See vendor | Desktop browser | Gmail, Outlook and web apps | No — a Space per account | No |
| Gmail account switcher | Free | Browser | Google only | No — one at a time | Partial |
| Postbox | Free, no paid tier | Browser | Gmail and Workspace only | Yes | No |
Pricing is given as a model rather than a figure on purpose. Every vendor here changes its prices more often than this page is reviewed, and a stale number would make the accurate rows look unreliable too. Follow each link for the current price. Shift reads “see vendor” because it has repositioned as a browser and its tiers no longer map cleanly onto the others.
Why these criteria
- Providers decides most choices on its own. If one account is Outlook, the Gmail-only options are out before anything else is considered.
- Combined list is the thing people mean by “unified inbox”, and not every tool marketed that way actually provides one — Shift and Gmail’s switcher both show accounts separately.
- Offline separates desktop from browser, permanently. A browser app fetches mail on demand; there is no version of it that works on a plane.
- Runs as matters if you move between machines. A desktop client has to be installed and configured on each one.
Where Postbox loses
Worth stating plainly, since this is our page. Postbox does not do offline. It does not support Outlook, Yahoo, iCloud or any IMAP mailbox — Gmail and Google Workspace only. It has none of the power features the desktop clients have built over a decade: no smart folders, no templates, no add-ons, no local archive. It is maintained by one person, with no uptime guarantee.
There is also a live constraint on access. Gmail’s read and send permissions are restricted scopes that require Google verification and a third-party security assessment; until that completes a deployment runs in Google’s Testing mode, where only listed test users can connect and access expires every seven days. That is explained in how it works.
How this was put together
Facts about each option come from that vendor’s own current public documentation, linked in the table above, and from Google’s help pages for the account switcher. Nothing here is drawn from a third-party traffic or ranking estimate, and no vendor was contacted or consulted. Claims about Postbox come from its own source code and are documented on how it works and privacy and security.
Competitor facts change. This page carries a reviewed date at the top, and the intent is to re-check every option quarterly; if the date is old, treat the table as a starting point and confirm against the vendor links.
Common questions
What is the best free way to read several Gmail accounts in one place?
Thunderbird is the strongest free desktop option: unlimited accounts, a real unified inbox and offline access, at no cost. Postbox is the free option that needs no installation. Gmail’s own account switcher is free too but shows one account at a time.
Which option works with Outlook and other non-Gmail accounts?
The desktop clients do. Thunderbird, eM Client and Mailbird all connect any IMAP mailbox, including Outlook, Yahoo and iCloud. Postbox does not — it connects Gmail and Google Workspace accounts only.
Which option works offline?
Only the desktop clients. Thunderbird, eM Client and Mailbird keep a local copy of your mail, so you can read and draft without a connection. Postbox and Shift both render mail in a browser and fetch it on demand, so both need a connection.
What should I use now that the Postbox desktop client is discontinued?
eM Client is the successor its own vendor points to, and its setup wizard imports Postbox accounts, settings and contacts. Thunderbird is the free client Postbox was originally built from. Neither is related to this website, which shares only the name.
Postbox · Managing multiple Gmail accounts· What is a unified inbox?· The discontinued Postbox client·