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Developer Tools · head to head

Atlantis vs GNAT Pro

Atlantis logo

Atlantis

Developer Tools

Runs Terraform plan and apply from pull request comments, self-hosted and free

From
Free
Rated
-
Full reviewWebsite
GNAT Pro logo

GNAT Pro

Developer Tools

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

From
On request
Rated
-
Full reviewWebsite

The short version

  • Only Atlantis has a free tier, so it costs nothing to try first.
  • Each has a real cost: Atlantis there is no company, no service level agreement and no paid support at any price, and the six maintainers are volunteers with day jobs, which some risk committees will not accept for a component holding production cloud credentials.; GNAT Pro no pricing published on website; requires contacting AdaCore directly for quotes
  • Prices and features above were last checked on 31 August 2026.

Where they differ

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

Attributes where Atlantis and GNAT Pro differ
AttributeAtlantisGNAT Pro
Starting priceFreeOn request
Pricing modelOpen source, no licence feequote
Free tierYesNo
PlatformsLinux, Docker, Kubernetes, Self-hostedWeb

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

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 Atlantis

  • Pull request plans
  • Comment driven apply
  • Workspace locking
  • Policy checking
  • Multi-platform webhooks
  • Custom workflows

Only in GNAT Pro

Nothing recorded that Atlantis does not also cover.

What people use each for

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

Atlantis

  • Making Terraform review meaningful by putting the actual plan output in front of the approvernot GNAT Pro
  • Removing local applies and the credential sprawl that comes with every engineer holding production keysnot GNAT Pro
  • Getting pull request driven infrastructure without paying a per-user subscription for a hosted platformnot GNAT Pro
  • Enforcing Conftest policies as a blocking check before an apply can runnot GNAT Pro

GNAT Pro

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

Where each one falls short

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

Atlantis

  • There is no company, no service level agreement and no paid support at any price, and the six maintainers are volunteers with day jobs, which some risk committees will not accept for a component holding production cloud credentials.
  • The security surface is inherently sharp, because it is an internet-reachable webhook endpoint that executes applies with privileged credentials, gated by pull request comment authorisation that is coarse next to a real policy engine.
  • It is stateful, holding a working directory and lock database on local disk, so high availability and horizontal scaling are awkward and you own upgrades, webhook plumbing, secret rotation and the host itself.
  • It lacks the features that distinguish the commercial alternatives, with no native drift detection, no cost estimation, no managed state interface and no policy engine beyond the Conftest integration.
  • Terragrunt and monorepo layouts are not first-class, requiring hand-written custom workflows and repository configuration that becomes a growing maintenance burden as the number of repositories increases.

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

Atlantis

Free
  • AtlantisFree
    • Apache-2.0, no usage limits and no seat count
    • No commercial edition and no paid support tier
    • Community support through GitHub and the CNCF Slack channel

GNAT Pro

On request

No published plan breakdown. See the GNAT Pro review.

Which should you pick?

Choose Atlantis if

  • You need pull request plans.
  • You want to start without paying.
  • You work on Linux, Docker, Kubernetes, Self-hosted.
  • You also want comment driven apply.
Atlantis review

Choose GNAT Pro if

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

GNAT Pro review

Questions people ask

Is Atlantis or GNAT Pro better?
Neither clearly leads. Atlantis 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, Atlantis or GNAT Pro?
Atlantis has a free tier; the other does not. Paid plans start at Free for Atlantis and On request for GNAT Pro.
Does Atlantis or GNAT Pro run on more platforms?
Atlantis runs on Linux, Docker, Kubernetes, Self-hosted. GNAT Pro runs on Web.
Can I use Atlantis for free?
Yes. Atlantis has a free tier, so you can try it without paying. GNAT Pro starts at On request.
What is Atlantis best used for?
Atlantis is most often used for making terraform review meaningful by putting the actual plan output in front of the approver, removing local applies and the credential sprawl that comes with every engineer holding production keys, getting pull request driven infrastructure without paying a per-user subscription for a hosted platform, enforcing conftest policies as a blocking check before an apply can run. Of those, making terraform review meaningful by putting the actual plan output in front of the approver and removing local applies and the credential sprawl that comes with every engineer holding production keys are not what GNAT Pro is typically brought in for.
What can Atlantis do that GNAT Pro cannot?
Atlantis covers Pull request plans, Comment driven apply, Workspace locking, Policy checking.

Answered from the vendors’ own pages

Atlantis: Is there a company behind Atlantis?

No. It runs as a series of LF Projects under the Linux Foundation and is maintained by volunteers. There is no vendor to buy support from and no service level agreement.

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
Atlantis: Is it a CNCF project?

No. It uses a channel in the CNCF Slack, which is often misread as membership, but the project sits under LF Projects rather than the CNCF.

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
Atlantis: Does it work with OpenTofu?

Yes, there is a dedicated integration guide alongside Terraform, and it also has configuration for working with hosted Terraform backends.

Atlantis: What does it not do that a paid platform does?

Drift detection, cost estimation, a managed state and run interface, and a real policy engine. Atlantis does pull request plan and apply well and stops there.

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