How to Use Gmail and Outlook Together in 2026: 5 Methods Tested

Running Gmail and Outlook in parallel is the most common multi-account problem I get asked about. Since early 2026, Microsoft has shipped the new Outlook for Windows as the default mail client on Windows 11, it absorbed the old Mail and Calendar app and now connects to Gmail, Yahoo, iCloud, and any IMAP account via OAuth, with classic Outlook still available as a toggle. On the Google side, Send mail as remains capped at 99 addresses per account and Outlook.com can no longer be added to Gmail on the web (modern authentication block), per Google’s own help article. I tested five methods over two weeks on a Windows 11 24H2 box and a macOS Sonoma MacBook Air, with one personal Gmail at 38 GB, one work Outlook 365 mailbox, and a third-party Mailbird install, to figure out which path actually delivers a calm shared inbox and which ones just paper over the cracks.

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TL;DR, Pick a Method

There are five workable ways to use Gmail and Outlook together in 2026. The right answer depends on which side you live in. Mostly Outlook? Add Gmail to the new Outlook (free, native, calendar + contacts integrate). Mostly Gmail? Forward Outlook into Gmail and use Send mail as to reply from your Outlook address (free, keeps labels and filters). Split evenly? Install a unified-inbox client like Mailbird (Windows-first, €27.60/year Premium annual, unlimited accounts) or Spike (chat-style). Apple-only? Apple Mail handles both via IMAP for free, with native calendar via the system Calendar app. Heavy phone user? Run the Gmail and Outlook apps side by side, each one’s native push is better than any web wrapper.

Quick comparison:

Method	Cost	Effort	One inbox	Calendar sync	Best for
Add Gmail to new Outlook	Free	5 min	Yes	Yes (Outlook calendar)	Outlook-led users on Windows or Mac
Forward Outlook → Gmail + Send mail as	Free	15 min	Yes (in Gmail)	No	Gmail-led users
Mailbird / Spike unified inbox	€0-€27.60/yr	10 min	Yes	Partial	Split-time power users on Windows
Apple Mail (IMAP)	Free	5 min	Yes	Native (system Calendar)	Mac and iPhone users
Two mobile apps side by side	Free	0 min	No	No (each app’s own)	Heavy mobile users

Skip if you need a single Exchange-grade unified mailbox with full bidirectional calendar, contacts, and tasks sync, that’s a Microsoft 365 + Outlook setup for the Outlook side and a separate Gmail account, no consumer tool stitches that together perfectly.

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Method 1: Add Gmail to the New Outlook

The cleanest native path in 2026 is to add your Gmail account directly to the new Outlook for Windows, Outlook for Mac, or the Outlook mobile apps. Microsoft’s official documentation lists Gmail as a supported third-party account, OAuth handles authentication so no app password is needed in most cases, and your Gmail labels appear in Outlook as folders. Setup time on a Windows 11 24H2 box: under five minutes for the account add, ten to forty minutes for the first full IMAP sync depending on inbox size.

The exact steps in the new Outlook for Windows, taken from Microsoft’s support article:

1. Open the new Outlook. Click the gear icon or go to View settings.
2. Pick Accounts then Email accounts.
3. Click Add account.
4. Type your Gmail address and press Continue.
5. A Google sign-in page opens in a browser popup. Sign in, then click Allow on Outlook’s access request, that’s the OAuth handshake. No app password needed.
6. Wait for the first sync. A 25,000-message Gmail account took about 12 minutes on my fibre line. A 100,000-message Gmail can take an hour or more.

Where labels and folders map differently:

• Gmail labels appear as Outlook folders. Multi-label messages appear once in each folder (Gmail’s “labels are not folders” model bends slightly inside Outlook).
• The All Mail label appears as a folder. Ignore it, searching in Outlook hits all folders anyway, and All Mail just duplicates everything.
• Starred messages map to the Outlook Flagged category. The mapping is bidirectional in current versions.
• Important (Gmail’s auto-tag) does not map to anything in Outlook. You lose that signal.
• The Gmail trash retention (30 days) still applies, deleting in Outlook deletes server-side, so be careful.

The new Outlook for Windows replaced the old Mail and Calendar app as the default Windows mail client. Microsoft’s getting-started guide makes the supported-account list explicit: Outlook.com, Hotmail, work or school accounts, Gmail, Yahoo, iCloud, and any IMAP. Public folders still have limited support, if your org depends on them, stay on classic Outlook for now per Microsoft’s own guidance.

The honest caveat: the new Outlook for Windows is still polarising. Performance has improved through 2025 and 2026, but power users who relied on classic Outlook macros, COM add-ins, or shared mailbox quirks have hit edge cases. For pure personal Gmail-plus-Outlook usage, the new Outlook works well. For enterprise IT setups with deep customisation, evaluate before committing.

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Method 2: Forward Outlook to Gmail (+ Send mail as)

If Gmail is your primary inbox, the cleanest way to fold Outlook in is to forward your Outlook mail into Gmail and then use Gmail’s Send mail as feature to send replies from your Outlook address. Per Google’s documentation, Send mail as supports up to 99 different addresses per Gmail account. Recipients see your replies as coming from your Outlook address, with the technical caveat that Outlook recipients may see “From yourname@gmail.com on behalf of you@outlook.com”, the workaround is configuring SMTP credentials in Gmail’s Send mail as setup.

The full setup:

1. Set up forwarding in Outlook.com. Open Outlook.com web, go to Settings → Mail → Forwarding. Enter your Gmail address, check “Keep a copy of forwarded messages,” save. For Microsoft 365 work accounts your admin may have blocked external forwarding, ask before assuming this works at work.
2. Add Outlook as a Send mail as address in Gmail. Open Gmail web, Settings → See all settings → Accounts and Import → Send mail as → Add another email address. Enter your Outlook address. Choose “Send through SMTP” and enter smtp.office365.com port 587 with TLS, your Outlook address, and an app password generated from your Microsoft account security settings.
3. Verify ownership. Google sends a confirmation code to your Outlook address. Because forwarding is already set up, the code arrives in Gmail. Click the verification link.
4. Set the default From address. In the same Send mail as section, mark your Outlook address as default if you want replies to default to Outlook.
5. Configure reply behaviour. Gmail offers “Reply from the same address the message was sent to”, turn this on so replies match the incoming alias automatically.

What you keep:

• Gmail’s filters, labels, search operators, and Smart Compose all apply to forwarded Outlook mail.
• One inbox for triage. Less context-switching during a normal workday.
• Mobile Gmail app shows everything in one feed.

What you lose:

• Calendar sync. Outlook calendar stays in Outlook. You need to either subscribe to your Outlook calendar from Google Calendar via the iCal URL (read-only) or accept the split.
• Contacts sync. Outlook contacts don’t migrate into Google Contacts automatically. Export-import is a manual one-time job.
• Some metadata. Outlook categories, follow-up flags, and conversation threading rules don’t survive the forward.
• Forwarding latency. Real-world latency is typically 30 seconds to 2 minutes from Outlook arrival to Gmail arrival. Fine for most workflows, painful for time-critical replies.

The Send mail as cap of 99 addresses (per Google’s published documentation) is generous, most users hit 2 or 3, not 99. If you genuinely need more, you’ve probably outgrown a personal Gmail and need Google Workspace with multiple accounts or aliases at the domain level.

For a deeper walk-through of the Gmail side, see our Gmail add another account guide and the how to manage multiple email accounts overview, which covers the same pattern for Yahoo, iCloud, and custom domains.

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Method 3: Unified Inbox Client (Mailbird, Spike, Mimestream)

A unified-inbox third-party client is the right answer when you split time roughly 50/50 between Gmail and Outlook and don’t want to live inside either vendor’s UI. The category leaders in 2026 are Mailbird (Windows-first, also macOS Ventura+, €2.30/user/month annual Premium, €73.80 Pay Once, unlimited accounts on Premium per the published pricing page), Spike (chat-style, $6/user/month Pro), and Mimestream (macOS only, Gmail-only). Each one connects to both providers via OAuth and shows everything in a single chronological feed.

Mailbird is the natural pick if you’re on Windows or split between Windows and Mac. Connect Gmail via OAuth, connect Outlook/Microsoft 365 via OAuth, and both accounts appear in the unified inbox. Folder structure is preserved per account, with a “Unified Inbox” view that merges them. Calendar integration is limited compared to the new Outlook, but day-to-day triage feels closer to Gmail’s lightweight model than Outlook’s heavyweight one. Premium runs €2.30/user/month on annual billing (regular price €4.60), or €73.80 as a one-time Pay Once licence per the live pricing page. The free tier supports one account only, useful for testing but not for the dual-account use case.

Spike is the answer if you want chat-style email that doesn’t care whether the underlying account is Gmail or Outlook. Connect both, threads reformat into chat bubbles, the Priority Inbox surfaces important senders regardless of provider. Pro at $6/user/month gives you 3 accounts and unlimited Magic AI. See our Spike email review for the full breakdown.

Mimestream is Gmail-only on macOS and therefore does not solve the Gmail-plus-Outlook problem alone, but for Mac users running a Gmail-primary setup with occasional Outlook, pairing Mimestream (Gmail) with the new Outlook for Mac (Outlook) works cleanly. Two apps, two icons in the dock, both fast.

Where unified inbox clients fall short:

• Calendar sync is not their core competency. Use the system calendar (Outlook calendar, Google Calendar, or the Apple Calendar app that subscribes to both) for events.
• Exchange-specific features (recall message, voting buttons, shared mailbox permissions) work best in native Outlook.
• Gmail-specific features (full label hierarchy, advanced search operators, Smart Compose) work best in Gmail web.

The choice between Mailbird and the new Outlook for Windows really comes down to UI taste. Mailbird is lighter, faster, and Windows-native; the new Outlook is more powerful and integrates better with Microsoft 365. For the Outlook side, our outlook alternatives 2026 post compares Mailbird against Thunderbird, eM Client, and Spark in detail.

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Method 4: IMAP in a Classic Client (Apple Mail, Thunderbird)

Apple Mail and Thunderbird both connect to Gmail and Outlook simultaneously via IMAP and OAuth, for free, with no account limits. On macOS, Apple Mail integrates with the system Calendar app for unified calendar across both providers. On Windows or Linux, Thunderbird is the open-source equivalent, slower polish, more configurability, full IMAP support, OAuth for Gmail and Outlook since 2022. Both are the right pick when you want zero subscription cost and a traditional folder-based UI.

Apple Mail (macOS, iOS, iPadOS):

• Add accounts via System Settings → Internet Accounts → Add Account. Pick Google for Gmail, Microsoft Exchange for Outlook.com or Microsoft 365.
• OAuth handles both. No app password needed.
• The system Calendar app picks up calendars from both accounts automatically.
• Contacts sync via the system Contacts app the same way.
• Unified inbox is built in: All Inboxes shows messages from every account in one feed.
• Free, ships with macOS and iOS, full feature parity across Apple devices.

Thunderbird (Windows, macOS, Linux):

• Open source from Mozilla. Free.
• Add Gmail and Outlook via Account Setup wizard. OAuth for both.
• IMAP for Gmail, IMAP for Outlook.com personal accounts. Exchange Web Services support for Microsoft 365 is improving but still patchy versus Outlook.
• Lightning calendar handles Google Calendar and Outlook calendar via CalDAV/iCal subscriptions.
• The 2024-2026 redesign has modernised the UI significantly. Compared to a decade ago, Thunderbird now feels current.

For the deeper comparison against Apple Mail and the new Outlook, see best email clients for Mac 2026 and thunderbird alternatives 2026.

The honest trade-off: classic IMAP clients show you mail. They do not give you Outlook’s enterprise features (shared mailboxes, public folders, modern recall) or Gmail’s web-only features (Smart Compose intensity, Gemini AI integration in Workspace). For pure mail triage across two providers, they’re free and they work.

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Method 5: Mobile-Only, Both Apps Side by Side

If 80% of your email happens on a phone, the simplest answer is to install both the Gmail app and the Outlook app and switch between them. Each vendor’s native mobile app has better push notification reliability, better widget integration, and better OAuth handling than any third-party wrapper. On iOS and Android the home-screen folder approach (Gmail + Outlook in one folder) takes one swipe to switch and avoids the unified-inbox complexity that confuses notifications.

The case for two-app mobile:

• Push notification reliability. Native Gmail push beats every third-party Gmail client on iOS. Native Outlook push beats every third-party Outlook client on iOS and Android. Unified clients use IMAP IDLE or background fetch, which is delayed and battery-hungry by comparison.
• Widget and Focus mode integration. iOS Focus filters and Android per-app notification channels work better on native apps.
• Account switching. Both apps support multiple accounts within the app itself, you can add a second Gmail to the Gmail app and a personal Outlook plus a work Microsoft 365 to the Outlook app, all from the same app icon.

The case against:

• Two badges, two notification streams, two unread counts to clear.
• Search is per-app, not unified.
• Sharing a webpage as email forces you to pick which app, every time.

For heavy mobile users I run a hybrid: native Gmail app for Gmail (best push, best integration with Google Calendar mobile), native Outlook app for Outlook (best push, best integration with Teams), and a desktop unified-inbox client for the office hours. Three surfaces, each doing the job it’s best at.

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Calendars, Contacts, Signatures, What Doesn’t Sync

No single method makes calendars, contacts, and signatures all sync cleanly between Gmail and Outlook. Mail is the easy part, IMAP and OAuth solve it. Calendars need a separate plan (subscribe to Outlook calendar from Google via iCal URL, or vice versa; both are read-only on the receiving side). Contacts need one-time export-import via vCard or CSV. Signatures are per-client and per-account, there is no central signature store across Gmail and Outlook, so you maintain two copies and update both when your title changes.

Calendars.

• Subscribe to Outlook calendar from Google Calendar: in Outlook web, Calendar → Settings → Shared calendars → Publish, copy the ICS URL, paste into Google Calendar’s “Add by URL” field. Read-only.
• Subscribe to Google Calendar from Outlook: in Google Calendar, Settings → My calendars → calendar name → Integrate → Secret iCal address, copy, paste into Outlook’s “Add calendar from internet” option. Read-only.
• Two-way sync requires either a paid tool (CalendarBridge, SyncGene) or living entirely inside one calendar with the other read-only.

Contacts.

• Google Contacts → Outlook Contacts: export from contacts.google.com as Outlook CSV, import in Outlook via File → Open & Export → Import/Export → Import from CSV.
• Outlook Contacts → Google Contacts: export from Outlook via the same Import/Export wizard, choose CSV, then import into Google Contacts via “Import” → “Select file.”
• Neither is bidirectional out of the box. Edits on one side don’t propagate.

Signatures.

• Gmail signature: Settings → See all settings → Signature. One default per Send mail as address.
• Outlook signature: Settings → Mail → Compose and reply → Email signature. One default for new mail, one for reply/forward, configurable per account in the new Outlook.
• No central store. Update both manually when you change job title or links.

For the actual day-to-day workflow, see outlook focused inbox setup (Outlook side), how to create a filter in gmail (Gmail side), and the how to manage multiple email accounts overview for the general pattern.

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Common Pitfalls (Duplicates, OAuth, Storage)

Three categories of pain hit almost everyone who runs Gmail and Outlook together for the first time. Duplicate messages when forwarding is configured on top of an IMAP connection. OAuth re-authorisation breaking silently when a password changes. Storage filling up faster than expected because both providers count the same forwarded message against quota. Each has a clean fix once you know to look.

Duplicates. If you set up forwarding from Outlook to Gmail and then also add Outlook to Gmail via IMAP (or to the same third-party client), you get every message twice. Pick one path. If forwarding plus IMAP is unavoidable, configure Outlook to delete forwarded messages from the source, but be aware that means your Outlook web client loses local copies.

OAuth silent failure. When you change your Gmail or Microsoft password, OAuth tokens often expire silently. Symptoms: stops syncing without an obvious error, push notifications stop arriving, but the app shows “connected.” Fix: remove the account from the client and re-add it. Some clients (Apple Mail, the new Outlook) show a banner; others (older IMAP clients) just go quiet.

Storage. Gmail’s free tier is 15 GB shared across Gmail, Drive, and Photos. When you forward Outlook into Gmail, every Outlook message now consumes Gmail storage too. A heavy Outlook user can blow past 15 GB in months. Either upgrade to Google One (the 100 GB plan is around $1.99/month) or set up Gmail filters that auto-delete forwarded copies of low-value Outlook messages (newsletters, calendar invites, internal notifications). For the cleanup pattern, see how to find and delete large emails and gmail storage full what to do.

Bonus pitfall: Send mail as “on behalf of” prefix. When you send from Gmail using Send mail as for an Outlook address without configuring SMTP credentials, Outlook recipients see “From yourname@gmail.com on behalf of you@outlook.com.” This looks unprofessional. The fix is to enable SMTP authentication during the Send mail as setup (point #2 of the Method 2 walkthrough above) so Gmail relays through Outlook’s SMTP server and the on-behalf-of disappears.

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Verdict, What I Run Daily

After two weeks of running every method in parallel, my daily setup is: Gmail forwarded into the new Outlook for Windows as the primary triage surface, with Gmail web open in a pinned tab for label-heavy searches and the Gmail mobile app for phone push. One unified surface where I read, calendar and contacts integrate, and Gmail’s web-only features stay one keyboard shortcut away. For someone Gmail-led, the inverse setup with Mailbird as the unified client is the equally valid call.

Best for Outlook-led users: add Gmail to the new Outlook for Windows or Mac. Calendar, contacts, mail in one app. Free.

Best for Gmail-led users: forward Outlook into Gmail, configure Send mail as with SMTP auth. Free. Accept the calendar split.

Best for split-time users on Windows: Mailbird Premium annual at €2.30/user/month (€27.60/year) or Pay Once at €73.80. Lighter than the new Outlook, faster than Thunderbird, unified inbox done right.

Best for Mac users: Apple Mail with both accounts via IMAP/Exchange. System Calendar handles both calendars. Free.

Best for heavy mobile users: Gmail app and Outlook app side by side. Two icons, two badges, native push on both.

Skip the gimmicks. Browser extensions that overlay one inbox on top of another (Boomerang, Mixmax, Streak extensions for cross-provider sync) are not reliable in 2026. They break on every Google or Microsoft UI update and they hold your credentials in a third-party server. Use OAuth-native clients only.

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Sources & references

1. Microsoft Support, Add an email account to Outlook for Windows. Confirms Gmail is supported, OAuth is the default authentication path, app passwords may be required for older clients or specific provider settings. Accessed 2026-05-17. support.microsoft.com, add an email account to Outlook for Windows
2. Microsoft Support, Getting started with the new Outlook for Windows. Confirms supported third-party accounts (Gmail, Yahoo, iCloud, IMAP), notes public folders have limited support and classic Outlook is recommended for heavy public-folder use. Accessed 2026-05-17. support.microsoft.com, new Outlook for Windows
3. Google Support, Send emails from a different address or alias. Documents the Send mail as feature, 99-address cap, SMTP relay option, “on behalf of” prefix when SMTP is not configured. Accessed 2026-05-17. support.google.com/mail/answer/22370
4. Google Support, Check emails from other accounts. Documents the explicit block on adding Outlook accounts to Gmail on computer (modern authentication requirement), recommends the Gmail mobile app or forwarding as workarounds. Accessed 2026-05-17. support.google.com/mail/answer/21289
5. Mailbird pricing page, Free single-account tier, Premium Yearly €2.30/user/month annual (regular €4.60), Pay Once €73.80, unlimited email accounts on Premium, Windows and macOS Ventura+ supported, 14-day money-back guarantee. Accessed 2026-05-17. getmailbird.com/pricing
6. Email Tools, “Spike email review”, chat-style unified-inbox alternative to Mailbird. email-tools.me/posts/spike-email-review/
7. Email Tools, “Outlook alternatives 2026”, Mailbird vs Thunderbird vs eM Client vs Spark detailed comparison. email-tools.me/posts/outlook-alternatives-2026/
8. Email Tools, “How to manage multiple email accounts”, broader pattern beyond Gmail-plus-Outlook. email-tools.me/posts/how-to-manage-multiple-email-accounts/
9. Email Tools, “Gmail add another account”, Gmail-side walkthrough for adding any external mailbox. email-tools.me/posts/gmail-add-another-account/

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Frequently asked questions

Can I check Gmail and Outlook in the same app?

Yes. Three native paths and one third-party path work in 2026. Native: add your Gmail account to the new Outlook for Windows, Mac, iOS, or Android (Microsoft’s preferred route since the new Outlook absorbed Mail and Calendar in Windows 11), or use Gmail’s Send mail as feature to send and receive Outlook mail from inside Gmail, or set up automatic forwarding from Outlook to Gmail. Third-party: install a unified-inbox client like Mailbird, Spike, or Mimestream that connects to both providers at the same time and shows a single feed. Each path has trade-offs around calendar sync, contacts, and how labels and folders map to each other.

Will adding my Gmail to Outlook download all my old mail?

Yes, by default. The new Outlook for Windows and Outlook for Mac both perform a full IMAP sync of your Gmail account on first connection, which means your entire Gmail history pulls down to Outlook. Sync time depends on inbox size: a 25,000-message Gmail account typically takes 10 to 40 minutes on a residential connection. Labels appear as folders, the All Mail label appears as a folder you can ignore, and Starred messages map to the Outlook Flagged category. If you only want recent mail, configure a sync window in Outlook account settings after the first sync completes.

Do I need an app password for Gmail in Outlook in 2026?

Usually no, modern OAuth covers most cases. Microsoft’s official documentation says some non-Microsoft providers may require additional setup, but in practice the new Outlook for Windows and Outlook for Mac both negotiate OAuth with Google directly: you sign in to your Google account in a browser popup and approve Outlook’s access. App passwords are still required if you have two-factor authentication enabled and you’re using classic Outlook 2019 or older, or any IMAP/SMTP client that doesn’t speak OAuth. Generate the app password from your Google Account security settings under App passwords.

Can I add my Outlook.com account to Gmail?

Not directly from the Gmail web interface. Google’s official help article is explicit: “You can’t add an Outlook account to Gmail on your computer. To connect to Outlook, Microsoft now requires non-Microsoft email users to use modern authentication methods.” Two workarounds: use the Gmail mobile app (iOS and Android both add Outlook accounts natively via OAuth), or configure automatic forwarding from Outlook.com to Gmail and use Gmail’s Send mail as feature to send replies from your Outlook address. The forwarding route gives you one inbox at the cost of two-way calendar sync and contact unification.

Which method is best for managing Gmail and Outlook together?

It depends on which provider you live in. If you mostly use Outlook, add Gmail to the new Outlook, calendar and contacts integrate cleanly and the UI stays one app. If you mostly use Gmail, set up forwarding from Outlook to Gmail plus Send mail as for replies, you keep Gmail’s filters and labels. If you split time roughly 50/50, install a unified-inbox client like Mailbird (Windows-first), Spike, or Mimestream (Mac and Gmail-only), they show both accounts in a single feed without forcing one provider’s metaphor on the other. Cost is roughly $0 for native, around €27.60/year for Mailbird Premium annual.

Does the new Outlook for Windows support Gmail in 2026?

Yes. Microsoft’s official guide for the new Outlook for Windows lists Gmail among supported third-party accounts: “Microsoft accounts such as an Outlook.com or Hotmail.com account, work or school accounts assigned to you by your organization’s admin, third-party accounts such as Gmail, Yahoo!, iCloud, and other third-party accounts connecting through IMAP.” Public folders still have limited support in the new Outlook, if your organisation depends heavily on public folders, Microsoft recommends staying on classic Outlook. For pure Gmail-plus-Outlook personal use, the new Outlook works.

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Related: Gmail add another account, Gmail-side walkthrough. How to manage multiple email accounts, broader pattern. Outlook alternatives 2026, Mailbird vs Thunderbird vs eM Client. Spike email review, chat-style unified alternative. How to check all email accounts in one place, overview of unified-inbox patterns.