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Cybersecurity · head to head

Proton Mail vs Unit21

Proton Mail logo

Proton Mail

Cybersecurity

Secure email that protects your privacy

From
Free
Rated
-
Full reviewWebsite
Unit21 logo

Unit21

Cybersecurity

No-code fraud and AML risk operations platform for fintechs and neobanks

From
On request
Rated
-
Full reviewWebsite

The short version

  • Only Proton Mail has a free tier, so it costs nothing to try first.
  • Each has a real cost: Proton Mail paid plan pricing not displayed on vendor site; Unit21 it is built for fintech scale rather than card issuer scale, so organisations reaching very high transaction volumes generally re-evaluate against heavier platforms and face a migration.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Proton Mail and Unit21 actually diverge.

Attributes where Proton Mail and Unit21 differ
AttributeProton MailUnit21
Starting priceFreeOn request
Pricing modelfreemiumquote
Free tierYesNo

Identical on both: platforms (Web), user rating (Not yet rated), category (Cybersecurity).

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 Proton Mail

Nothing recorded that Unit21 does not also cover.

Only in Unit21

  • No-code rule builder
  • Case management
  • SAR filing
  • Backtesting
  • Identity and device signals
  • Data ingestion API

What people use each for

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

Proton Mail

  • Encrypted email communicationnot Unit21
  • Privacy-focused email servicenot Unit21
  • Family email protectionnot Unit21

Unit21

  • A neobank whose sponsor bank requires a documented monitoring programme before it will keep the BIN sponsorshipnot Proton Mail
  • A crypto exchange needing SAR filing and case management without building an internal compliance engineering teamnot Proton Mail
  • A payments startup where the fraud lead needs to ship a new rule the same day a new attack pattern appearsnot Proton Mail
  • A lender consolidating fraud alerts from three point tools into one investigator queue with a single audit trailnot Proton Mail

Where each one falls short

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

Proton Mail

  • Paid plan pricing not displayed on vendor site
  • Free tier limited to 1 GB storage
  • Free tier limited to single email address

Unit21

  • It is built for fintech scale rather than card issuer scale, so organisations reaching very high transaction volumes generally re-evaluate against heavier platforms and face a migration.
  • No-code rule authoring shifts power to the risk team, which is the point, but without governance it produces rule sprawl that nobody can explain to an examiner two years later.
  • Detection quality depends on the signals you feed it, so a thin integration produces thin results and the platform cannot compensate with proprietary consortium data the way larger vendors do.
  • Pricing is quoted by volume with an annual commitment, so a fintech whose growth stalls pays for headroom it did not use.
  • SAR filing coverage is oriented to United States FinCEN reporting, so firms filing in the United Kingdom, European Union or Asia handle those submissions outside the tool.

Pricing, plan by plan

Proton Mail

Free

No published plan breakdown. See the Proton Mail review.

Unit21

On request
  • Unit21 Platform$undefined/year
    • Priced by monitored volume and modules, annual contract
    • Fraud, AML and case management packaged separately
    • Implementation and historical data backfill quoted with the subscription

Which should you pick?

Choose Proton Mail if

  • You want to start without paying.
Proton Mail review

Choose Unit21 if

  • You need no-code rule builder.
  • You also want case management.
Unit21 review

Questions people ask

Is Proton Mail or Unit21 better?
Neither clearly leads. Proton Mail starts at Free and Unit21 at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Proton Mail or Unit21?
Proton Mail has a free tier; the other does not. Paid plans start at Free for Proton Mail and On request for Unit21.
Does Proton Mail or Unit21 run on more platforms?
Both run on Web, so platform support will not decide this one for you.
Can I use Proton Mail for free?
Yes. Proton Mail has a free tier, so you can try it without paying. Unit21 starts at On request.
What is Proton Mail best used for?
Proton Mail is most often used for encrypted email communication, privacy-focused email service, family email protection. Of those, encrypted email communication and privacy-focused email service are not what Unit21 is typically brought in for.
What can Proton Mail do that Unit21 cannot?
Unit21 covers No-code rule builder, Case management, SAR filing, Backtesting.

Answered from the vendors’ own pages

Proton Mail: Is there a free version of Proton Mail?

Yes, Proton Mail offers a free plan with 1 GB storage, 1 encrypted email address, and basic features like folders, labels, and filters.

Source
Unit21: Do we need engineers to run it?

Only for the initial data integration. After that the design intent is that risk and compliance staff author and deploy rules themselves.

Proton Mail: What does the Mail Plus plan include?

Mail Plus includes 15 GB storage, 10 encrypted email addresses, support for 1 custom domain, 10 hide-my-email aliases, priority support, and access to Proton Calendar.

Source
Unit21: Does it file SARs?

Yes, it generates and electronically files suspicious activity reports to FinCEN. Non-US regimes are not covered to the same depth.

Proton Mail: What is included in Proton Unlimited?

Proton Unlimited provides 500 GB storage, 15 email addresses, 3 custom domains, unlimited hide-my-email aliases, access to Mail, Calendar, VPN, Drive, and Pass, plus dedicated support.

Source
Unit21: Can we test a rule before it goes live?

Yes. Backtesting against historical data to see projected alert volume is one of the more useful parts of the product, because alert volume is the real cost.

Proton Mail: Does Proton Mail offer a money-back guarantee?

Yes, Proton Mail provides a 30-day money-back guarantee for paid plans.

Source
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