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Auth0 vs GNAT Pro

Auth0 logo

Auth0

Technology

Secure access for everyone

From
Free
Free plan
Yes
Full reviewWebsite
GNAT Pro logo

GNAT Pro

Developer Tools

Software development environments and toolchains for Ada, C/C++ and Rust

From
On request
Free plan
No
Full reviewWebsite

The short version

  • Only Auth0 has a free tier, so it costs nothing to try first.
  • Each has a real cost: Auth0 free tier limited to 25,000 monthly active users, requiring upgrade for growth beyond that; GNAT Pro no pricing published on website; requires contacting AdaCore directly for quotes
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Auth0 and GNAT Pro actually diverge.

Attributes where Auth0 and GNAT Pro differ
AttributeAuth0GNAT Pro
Starting priceFreeOn request
Pricing modelUnknownquote
Free tierYesNo
PlatformsWeb, iOS, AndroidWeb
CategoryTechnologyDeveloper Tools
Founded2013Unknown

Identical on both: 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 Auth0

  • Universal login
  • Social login
  • Multi-factor authentication
  • Passwordless
  • User management
  • Anomaly detection
  • Extensibility
  • Machine to machine

Only in GNAT Pro

Nothing recorded that Auth0 does not also cover.

What people use each for

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

Auth0

  • B2C authenticationnot GNAT Pro
  • B2B authenticationnot GNAT Pro
  • B2E authenticationnot GNAT Pro
  • API securitynot GNAT Pro
  • Mobile app securitynot GNAT Pro

GNAT Pro

  • Building certified avionics software meeting DO-178B/C standardsnot Auth0
  • Developing automotive embedded systems with ISO-26262 compliancenot Auth0
  • Integrating Ada, C/C++, and Rust components in single codebasenot Auth0
  • Managing software supply chain vulnerabilities and SBOMsnot Auth0
  • Supporting long-lived software systems spanning decadesnot Auth0

Where each one falls short

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

Auth0

  • Free tier limited to 25,000 monthly active users, requiring upgrade for growth beyond that
  • Advanced features like MFA and RBAC only available on paid Essentials tier and above
  • Ownership by Okta introduces risk that independent product roadmap may change

GNAT Pro

  • No pricing published on website; requires contacting AdaCore directly for quotes
  • Vendor indicates per-user, per-year subscription model but does not disclose specific costs

Pricing, plan by plan

Auth0

Free
  • FreeFree
    • Up to 25,000 monthly active users
    • Basic authentication
    • Email/password login
  • Essentials (B2C)$35/month
    • Unlimited MAUs beyond free tier
    • Multi-Factor Authentication
    • Role-Based Access Control
  • Professional (B2C)$240/month
    • All Essentials features
    • Advanced security
    • Custom branding

GNAT Pro

On request

No published plan breakdown. See the GNAT Pro review.

Which should you pick?

Choose Auth0 if

  • You need universal login.
  • You want to start without paying.
  • You work on Web, iOS, Android.
  • You also want social login.
Auth0 review

Choose GNAT Pro if

Nothing in the data separates GNAT Pro from Auth0 on the points above - pick on price and on how each one feels to use.

GNAT Pro review

Questions people ask

Is Auth0 or GNAT Pro better?
Neither clearly leads. Auth0 starts at Free and GNAT Pro at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Auth0 or GNAT Pro?
Auth0 has a free tier; the other does not. Paid plans start at Free for Auth0 and On request for GNAT Pro.
Does Auth0 or GNAT Pro run on more platforms?
Auth0 runs on Web, iOS, Android. GNAT Pro runs on Web.
Can I use Auth0 for free?
Yes. Auth0 has a free tier, so you can try it without paying. GNAT Pro starts at On request.
What is Auth0 best used for?
Auth0 is most often used for b2c authentication, b2b authentication, b2e authentication, api security. Of those, b2c authentication and b2b authentication are not what GNAT Pro is typically brought in for.
What can Auth0 do that GNAT Pro cannot?
Auth0 covers Universal login, Social login, Multi-factor authentication, Passwordless.

Answered from the vendors’ own pages

Auth0: How much does Auth0 cost?

Auth0 has a Free tier for up to 25,000 monthly active users (MAUs). Paid plans start at $35/month (Essentials B2C) and scale to $240/month (Professional B2C) and higher for Enterprise. Pricing scales with MAU usage.

Source
GNAT Pro: How much does GNAT Pro cost?

GNAT Pro pricing is not published on the website. Customers must request a pricing quote by contacting AdaCore directly or speaking with a GNAT Pro expert.

Source
Auth0: Does Auth0 include Multi-Factor Authentication?

No. MFA, RBAC (Role-Based Access Control), and premium support are not included in the free tier and require upgrading to paid Essentials plans or higher.

Source
GNAT Pro: What is GNAT Pro licensing model?

GNAT Pro is sold on a per-user, per-year basis with no license locks. Customers can request pricing for their specific needs.

Source
Auth0: Is Auth0 independent or part of a larger company?

Auth0 was acquired by Okta in May 2021 for $6.5 billion. It now operates as a subsidiary business unit within Okta, but maintains its own brand and operations.

Source
Auth0: Who should use Auth0 vs Okta?

Auth0 is developer-focused and serves customer identity use cases (B2C). Okta serves workforce identity (B2B) and has broader enterprise features. Auth0 now serves both markets post-acquisition but maintains its developer-friendly positioning.

Source
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