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ConfigCat vs Proton Mail

ConfigCat logo

ConfigCat

Developer Tools

Feature flag service priced per flag and environment with unlimited seats and unlimited monthly active users

From
Free
Free plan
Yes
Full reviewWebsite
Proton Mail logo

Proton Mail

Cybersecurity

Secure email that protects your privacy

From
Free
Free plan
Yes
Full reviewWebsite

The short version

  • Each has a real cost: ConfigCat there is no experimentation or statistical analysis engine, so teams wanting real A/B tests with significance testing must buy and integrate a separate analytics or experimentation product.; Proton Mail paid plan pricing not displayed on vendor site
  • Prices and features above were last checked on 31 August 2026.

Where they differ

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

Attributes where ConfigCat and Proton Mail differ
AttributeConfigCatProton Mail
Pricing modelPer month by feature flag and environment countfreemium
PlatformsWeb, API, iOS, Android, Node.js, .NET, Java, Python, GoWeb
CategoryDeveloper ToolsCybersecurity

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 ConfigCat

  • Feature flags and configuration
  • Percentage rollouts
  • Targeting rules and segments
  • Unlimited seats
  • Global CDN delivery
  • Audit log
  • Public API and webhooks
  • SDKs across languages

Only in Proton Mail

Nothing recorded that ConfigCat does not also cover.

What people use each for

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

ConfigCat

  • A consumer or mobile app with millions of users where per-MAU flag pricing would cost more than the flags are worthnot Proton Mail
  • A team that wants every engineer, product manager and support agent to have a login without paying per seatnot Proton Mail
  • Decoupling deployment from release with percentage rollouts and a kill switch, without buying an experimentation platformnot Proton Mail
  • A small team that needs ten flags permanently and can run indefinitely on the free tiernot Proton Mail

Proton Mail

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

Where each one falls short

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

ConfigCat

  • There is no experimentation or statistical analysis engine, so teams wanting real A/B tests with significance testing must buy and integrate a separate analytics or experimentation product.
  • Pricing by flag count punishes exactly the hygiene you want: the Pro tier caps at 100 flags, so teams that do not aggressively retire stale flags are pushed to the 325 dollar Smart tier for housekeeping reasons rather than growth.
  • The free tier allows only 2 environments, which does not cover the common development, staging and production split, so almost any real deployment starts on a paid plan.
  • It is a smaller vendor than the category incumbents, so enterprise procurement teams will find less depth in compliance attestations, contractual terms and reference architecture than LaunchDarkly offers.
  • Flag evaluation relies on SDK-side caching of a CDN-delivered config, which is fast but means propagation of a change is eventually consistent rather than instant, something to understand before relying on it as an emergency kill switch.

Proton Mail

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

Pricing, plan by plan

ConfigCat

Free
  • Forever FreeFree
    • 10 feature flags
    • 2 environments and 2 products
    • 2 segments
  • Pro$110/month
    • 100 feature flags
    • 3 environments and 3 products
    • Unlimited seats and MAUs
  • Smart$325/month
    • Unlimited feature flags
    • Unlimited environments, products and segments
    • Unlimited seats and MAUs
  • Enterprise$900/month
    • Everything in Smart
    • Enterprise support and controls
    • Unlimited everything on flag counts

Proton Mail

Free

No published plan breakdown. See the Proton Mail review.

Which should you pick?

Choose ConfigCat if

  • You need feature flags and configuration.
  • You want to start without paying.
  • You work on Web, API, iOS, Android, Node.js, .NET, Java, Python, Go.
  • You also want percentage rollouts.
ConfigCat review

Choose Proton Mail if

  • You want to start without paying.
Proton Mail review

Questions people ask

Is ConfigCat or Proton Mail better?
Neither clearly leads. ConfigCat starts at Free and Proton Mail at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, ConfigCat or Proton Mail?
ConfigCat starts at Free and Proton Mail at Free.
Does ConfigCat or Proton Mail run on more platforms?
ConfigCat runs on Web, API, iOS, Android, Node.js, .NET, Java, Python, Go. Proton Mail runs on Web.
Can I use ConfigCat for free?
Both have a free tier, so you can try either at no cost before committing.
What is ConfigCat best used for?
ConfigCat is most often used for a consumer or mobile app with millions of users where per-mau flag pricing would cost more than the flags are worth, a team that wants every engineer, product manager and support agent to have a login without paying per seat, decoupling deployment from release with percentage rollouts and a kill switch, without buying an experimentation platform, a small team that needs ten flags permanently and can run indefinitely on the free tier. Of those, a consumer or mobile app with millions of users where per-mau flag pricing would cost more than the flags are worth and a team that wants every engineer, product manager and support agent to have a login without paying per seat are not what Proton Mail is typically brought in for.
What can ConfigCat do that Proton Mail cannot?
ConfigCat covers Feature flags and configuration, Percentage rollouts, Targeting rules and segments, Unlimited seats.

Answered from the vendors’ own pages

ConfigCat: How is ConfigCat priced?

By feature flag, environment and product count. Seats, monthly active users and flag reads are unlimited on every plan.

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
ConfigCat: Is the free tier usable?

For small projects yes, but at 10 flags and 2 environments it will not cover a dev, staging and production setup.

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
ConfigCat: Can it run A/B tests?

It can split traffic, but there is no statistics engine. You need a separate analytics tool to decide a winner.

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
ConfigCat: How fast does a flag change take effect?

SDKs poll and cache, so changes propagate on the polling interval rather than instantly.

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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