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Utilities · head to head

Rectangle vs Spark Mail

Rectangle logo

Rectangle

Utilities

Free open source window snapping for macOS, with a separate paid Rectangle Pro for extra features

From
Free
Rated
-
Full reviewWebsite
Spark Mail logo

Spark Mail

Productivity

AI-assisted email client from Readdle with a Smart Inbox and team collaboration features

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Rectangle rectangle Pro is a separate app rather than an in-app purchase, so upgrading means installing and managing a second piece of software.; Spark Mail several sync features route mail metadata and, for some features, credentials through Readdle servers, which is a materially different trust model from a local-only IMAP client.
  • They diverge on capability: Rectangle covers Keyboard shortcuts, Spark Mail covers Smart Inbox.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Rectangle and Spark Mail actually diverge.

Attributes where Rectangle and Spark Mail differ
AttributeRectangleSpark Mail
Pricing modelOpen source, no licence feePer user per month
PlatformsMacmacOS, Windows, iOS, Android, Web
CategoryUtilitiesProductivity

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Rectangle

  • Keyboard shortcuts
  • Drag to snap
  • Multi-display support
  • Almost full screen
  • Rectangle Pro extras
  • Open source core

Only in Spark Mail

  • Smart Inbox
  • AI Copilot
  • AI Summaries
  • Team collaboration
  • Send later and snooze
  • Multi-account unified inbox

What people use each for

The jobs each tool is most often brought in to do.

Rectangle

  • A developer who wants source-available window management with no cost and no accountnot Spark Mail
  • Anyone replacing Magnet who does not want to pay even a small one-time feenot Spark Mail
  • A user who installs software via Homebrew rather than the Mac App Storenot Spark Mail
  • A power user who later wants Rectangle Pro extras but does not need them from day onenot Spark Mail

Spark Mail

  • A freelancer juggling Gmail and Outlook accounts who wants one AI-assisted inboxnot Rectangle
  • A small support team sharing a single inbox with internal notes before replyingnot Rectangle
  • Someone who wants drafts and summaries generated without switching to a new mail hostnot Rectangle
  • A user who wants notification triage without writing their own filtersnot Rectangle

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Rectangle

  • Rectangle Pro is a separate app rather than an in-app purchase, so upgrading means installing and managing a second piece of software.
  • It is Mac only, so it offers nothing for a user who also runs Windows and wants one window manager everywhere.
  • It has no official paid support channel, being a community open source project, so issues are handled through GitHub rather than a vendor support desk.
  • Some very old or unusually built third party apps still resist Rectangle window snapping, a limitation shared with most third party window managers on macOS.
  • Because it is not distributed through the Mac App Store, some users have to manually approve accessibility permissions and updates rather than getting silent App Store updates.

Spark Mail

  • Several sync features route mail metadata and, for some features, credentials through Readdle servers, which is a materially different trust model from a local-only IMAP client.
  • It is a client over accounts you still pay for elsewhere, so the total cost is Spark plus whatever Gmail, Outlook or Fastmail plan you already hold.
  • The free tier lacks AI Copilot and summaries, so the features it is best known for sit behind the paid plan.
  • Team features are basic next to dedicated shared-inbox tools like Front or Help Scout, so a support team scaling past a few agents will likely outgrow it.
  • Windows and Android versions have historically lagged the macOS and iOS apps in feature parity.

Pricing, plan by plan

Rectangle

Free
  • RectangleFree
    • Free and open source, no account needed
    • Keyboard and drag window snapping
    • Multi-display support
  • Rectangle Pro$9.99/one-time
    • Separate paid app, not an in-app unlock
    • Cursor-following snap areas
    • Per-app window size memory

Spark Mail

Free
  • BasicFree
    • Unlimited accounts
    • Smart Inbox
    • Basic send later
  • Premium$7.99/month
    • AI Copilot and summaries
    • Unlimited snooze and send later
    • Priority support
  • Premium Teams$10/month
    • Shared inboxes
    • Delegation and internal comments
    • Admin controls

Which should you pick?

Choose Rectangle if

  • You need keyboard shortcuts.
  • You want to start without paying.
  • You work on Mac.
  • You also want drag to snap.
Rectangle review

Choose Spark Mail if

  • You need smart inbox.
  • You want to start without paying.
  • You work on macOS, Windows, iOS, Android, Web.
  • You also want ai copilot.
Spark Mail review

Questions people ask

Is Rectangle or Spark Mail better?
Neither clearly leads. Rectangle starts at Free and Spark Mail at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Rectangle or Spark Mail?
Rectangle starts at Free and Spark Mail at Free.
Does Rectangle or Spark Mail run on more platforms?
Rectangle runs on Mac. Spark Mail runs on macOS, Windows, iOS, Android, Web.
Can I use Rectangle for free?
Both have a free tier, so you can try either at no cost before committing.
What is Rectangle best used for?
Rectangle is most often used for a developer who wants source-available window management with no cost and no account, anyone replacing magnet who does not want to pay even a small one-time fee, a user who installs software via homebrew rather than the mac app store, a power user who later wants rectangle pro extras but does not need them from day one. Of those, a developer who wants source-available window management with no cost and no account and anyone replacing magnet who does not want to pay even a small one-time fee are not what Spark Mail is typically brought in for.
What can Rectangle do that Spark Mail cannot?
Rectangle covers Keyboard shortcuts, Drag to snap, Multi-display support, Almost full screen. Spark Mail covers Smart Inbox, AI Copilot, AI Summaries, Team collaboration.

Answered from the vendors’ own pages

Rectangle: Is Rectangle really free?

Yes. The core app is free and open source with no feature gating or trial period.

Spark Mail: Does Spark host my email?

No. It is a client that connects to Gmail, Outlook, iCloud or any IMAP account; you still need a mail host.

Rectangle: What does Rectangle Pro add?

Cursor-following snap areas, per-app window size memory and some additional layouts, sold as a separate one-time purchase app.

Spark Mail: Does Spark store my email credentials on its servers?

For some features, including cross-device snooze and send-later sync, yes. It is part of how those features stay consistent across devices.

Rectangle: How is it different from Magnet?

Rectangle is free and open source; Magnet is a paid Mac App Store app from the start with no free tier.

Spark Mail: Is there a one-time purchase option?

No, Spark is subscription only for individuals and teams; the base client is free but AI and unlimited scheduling need Premium.

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