Cybersecurity · head to head
Clerk vs GNAT Pro

Clerk
Cybersecurity
Drop-in user authentication and management for developers
- From
- Free
- Rated
- -

GNAT Pro
Developer Tools
Software development environments and toolchains for Ada, C/C++ and Rust
- From
- On request
- Rated
- -
The short version
- Only Clerk has a free tier, so it costs nothing to try first.
- Each has a real cost: Clerk pricing scales with monthly retained users, which can grow expensive quickly for consumer apps with large user bases.; GNAT Pro no pricing published on website; requires contacting AdaCore directly for quotes
Where they differ
Only the attributes on which Clerk and GNAT Pro actually diverge.
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 Clerk
- Prebuilt UI components
- Organization management
- Multi-factor authentication
- Social sign-on
- Billing
- Enterprise connections
Only in GNAT Pro
Nothing recorded that Clerk does not also cover.
What people use each for
The jobs each tool is most often brought in to do.
Clerk
- Adding sign-in and user profiles to a web or mobile app quicklynot GNAT Pro
- B2B SaaS apps needing organizations and role-based accessnot GNAT Pro
- Startups wanting prebuilt UI instead of building auth in-housenot GNAT Pro
- Apps needing MFA and fraud detection out of the boxnot GNAT Pro
GNAT Pro
- Building certified avionics software meeting DO-178B/C standardsnot Clerk
- Developing automotive embedded systems with ISO-26262 compliancenot Clerk
- Integrating Ada, C/C++, and Rust components in single codebasenot Clerk
- Managing software supply chain vulnerabilities and SBOMsnot Clerk
- Supporting long-lived software systems spanning decadesnot Clerk
Where each one falls short
Documented limitations, not opinions. Every one is a constraint you would hit in normal use.
Clerk
- Pricing scales with monthly retained users, which can grow expensive quickly for consumer apps with large user bases.
- Enterprise SSO connections beyond the first are billed as add-ons, adding cost for larger organizations.
- The Business tier's extra dashboard seats cost $20/month each, which adds up for larger teams.
- Enterprise-tier features like the 99.99% uptime SLA require annual contracts rather than flexible monthly billing.
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
Clerk
Free- HobbyFree
- 50,000 MRU limit per app
- Up to 3 dashboard seats
- Unlimited applications
- Pro$25/month
- 50,000 MRUs included, $0.02/MRU overage
- Up to 3 dashboard seats
- 1 Enterprise Connection included
- Business$300/month
- 50,000 MRUs included with volume pricing
- 10 dashboard seats included
- SOC2 report and priority support
- Enterprise$undefined/month
- Custom pricing, annual billing
- 99.99% uptime SLA
- HIPAA available, dedicated Slack channel
GNAT Pro
On requestNo published plan breakdown. See the GNAT Pro review.
Which should you pick?
Choose Clerk if
- You need prebuilt ui components.
- You want to start without paying.
- You work on web, ios, android, api.
- You also want organization management.
Choose GNAT Pro if
Nothing in the data separates GNAT Pro from Clerk on the points above - pick on price and on how each one feels to use.
Questions people ask
- Is Clerk or GNAT Pro better?
- Neither clearly leads. Clerk 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, Clerk or GNAT Pro?
- Clerk has a free tier; the other does not. Paid plans start at Free for Clerk and On request for GNAT Pro.
- Does Clerk or GNAT Pro run on more platforms?
- Clerk runs on web, ios, android, api. GNAT Pro runs on Web.
- Can I use Clerk for free?
- Yes. Clerk has a free tier, so you can try it without paying. GNAT Pro starts at On request.
- What is Clerk best used for?
- Clerk is most often used for adding sign-in and user profiles to a web or mobile app quickly, b2b saas apps needing organizations and role-based access, startups wanting prebuilt ui instead of building auth in-house, apps needing mfa and fraud detection out of the box. Of those, adding sign-in and user profiles to a web or mobile app quickly and b2b saas apps needing organizations and role-based access are not what GNAT Pro is typically brought in for.
- What can Clerk do that GNAT Pro cannot?
- Clerk covers Prebuilt UI components, Organization management, Multi-factor authentication, Social sign-on.
Answered from the vendors’ own pages
Clerk: What does Clerk cost?
Clerk's Hobby plan is free with a 50,000 MRU limit; Pro is $25/month ($20/month billed annually), Business is $300/month ($250 annually), and Enterprise uses custom annual pricing.
SourceGNAT 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.
SourceClerk: Is there a free plan and what are its limits?
Yes, the Hobby plan is free with a 50,000 monthly retained user (MRU) limit per app, up to 3 dashboard seats, and unlimited applications, with no credit card required.
SourceGNAT 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.
SourceClerk: How is usage metered?
Clerk meters by monthly retained users (MRUs) — users who return to the app at least a day after signing up — with overage billed at $0.02 per MRU beyond the included 50,000 on paid plans.
SourceRelated pages
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