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Productivity · head to head

Capacities vs Fastmail

Capacities logo

Capacities

Productivity

A studio for your mind with object-based notes

From
Free
Rated
-
Full reviewWebsite
Fastmail logo

Fastmail

Productivity

Paid email hosting with custom domains, calendar and contacts, run without ad-based revenue

From
$3/month
Rated
-
Full reviewWebsite

The short version

  • Only Capacities has a free tier, so it costs nothing to try first.
  • Each has a real cost: Capacities pro plan pricing not prominently displayed on website; Fastmail it does not provide end-to-end encryption by default, so users specifically wanting zero-knowledge mail should compare it against Proton Mail or Tuta rather than assume parity.
  • They diverge on capability: Capacities covers Object-based notes, Fastmail covers Custom domain hosting.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Capacities and Fastmail actually diverge.

Attributes where Capacities and Fastmail differ
AttributeCapacitiesFastmail
Starting priceFree$3/month
Pricing modelUnknownPer user per month
Free tierYesNo
PlatformsWeb, macOS, Windows, Linux, iOS, AndroidWeb, iOS, Android, macOS, Windows
Founded2020Unknown

Identical on both: user rating (Not yet rated), category (Productivity).

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 Capacities

  • Object-based notes
  • Daily notes
  • Properties and relations
  • Graph view
  • AI assistant
  • Readwise
  • Web clipper
  • GDPR

Only in Fastmail

  • Custom domain hosting
  • Masked email
  • Unlimited aliases
  • Integrated calendar and contacts
  • Migration tools
  • JMAP support

What people use each for

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

Capacities

  • Productivitynot Fastmail
  • Collaborationnot Fastmail
  • Task managementnot Fastmail
  • Organizationnot Fastmail

Fastmail

  • Someone who wants their email address tied to a domain they own rather than a free provider they do notnot Capacities
  • A small business wanting hosted mail on its own domain without running mail server infrastructurenot Capacities
  • A person leaving Gmail specifically to stop an ad-funded provider processing their mailnot Capacities
  • A household migrating several accounts to one paid provider with shared billingnot Capacities

Where each one falls short

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

Capacities

  • Pro plan pricing not prominently displayed on website
  • Smaller community and ecosystem compared to Notion or Obsidian
  • Limited third-party integration marketplace

Fastmail

  • It does not provide end-to-end encryption by default, so users specifically wanting zero-knowledge mail should compare it against Proton Mail or Tuta rather than assume parity.
  • Moving to Fastmail is a real migration with DNS changes for a custom domain, unlike installing a client such as Spark or Bluemail over an existing account.
  • There is no free tier at all, so a user just wanting to try it commits to a paid trial rather than a permanently free option.
  • Storage limits on the entry Basic plan are modest next to the free allowance Gmail gives, and heavy attachment users will need Standard or above.
  • Being based in Australia means it falls under Australian data access law, which some privacy-focused buyers weigh differently from Swiss or German jurisdictions used by Proton Mail and Tuta.

Pricing, plan by plan

Capacities

Free
  • FreeFree
    • Unlimited spaces and objects
    • Device synchronization
    • Unlimited custom object types
  • Pro$10/month
    • Everything in Free
    • Unlimited notes
    • Advanced graph views
  • Believer$149.88/year
    • Everything in Pro
    • Beta access to new features

Fastmail

$3/month
  • Basic$3/month
    • 6GB storage
    • No custom domain support
    • Core mail, calendar and contacts
  • Standard$5/month
    • 60GB storage
    • Custom domain support
    • Masked email and aliases
  • Professional$9/month
    • 150GB storage
    • Multiple custom domains
    • Priority support

Which should you pick?

Choose Capacities if

  • You need object-based notes.
  • You want to start without paying.
  • You work on Web, macOS, Windows, Linux, iOS, Android.
  • You also want daily notes.
Capacities review

Choose Fastmail if

  • You need custom domain hosting.
  • You work on Web, iOS, Android, macOS, Windows.
  • You also want masked email.
Fastmail review

Questions people ask

Is Capacities or Fastmail better?
Neither clearly leads. Capacities starts at Free and Fastmail at $3/month, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Capacities or Fastmail?
Capacities has a free tier; the other does not. Paid plans start at Free for Capacities and $3/month for Fastmail.
Does Capacities or Fastmail run on more platforms?
Capacities runs on Web, macOS, Windows, Linux, iOS, Android. Fastmail runs on Web, iOS, Android, macOS, Windows.
Can I use Capacities for free?
Yes. Capacities has a free tier, so you can try it without paying. Fastmail starts at $3/month.
What is Capacities best used for?
Capacities is most often used for productivity, collaboration, task management, organization. Of those, productivity and collaboration are not what Fastmail is typically brought in for.
What can Capacities do that Fastmail cannot?
Capacities covers Object-based notes, Daily notes, Properties and relations, Graph view. Fastmail covers Custom domain hosting, Masked email, Unlimited aliases, Integrated calendar and contacts.

Answered from the vendors’ own pages

Capacities: What platforms does Capacities support?

Capacities is available on Web, Desktop (macOS, Windows, Linux), and Mobile (iOS, Android), allowing seamless work across devices.

Source
Fastmail: Is Fastmail a client like Spark, or does it host my email?

It hosts the mailbox itself; there is no separate provider underneath it the way Spark sits over Gmail.

Capacities: Does Capacities have a free plan?

Yes, Capacities offers a free plan with unlimited spaces, objects, and blocks, device synchronization, unlimited custom object types, and 5GB media uploads total.

Source
Fastmail: Does Fastmail offer end-to-end encryption?

Not by default in the way Proton Mail or Tuta do; its privacy position rests on being subscription-funded rather than ad-funded.

Capacities: What AI features does Capacities include?

Capacities includes an AI Assistant available on Pro and higher plans for brainstorming, summarization, and contextual Q&A about your notes.

Source
Fastmail: Can I use my own domain?

Yes, from the Standard plan up, with full alias and masked email support.

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