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Developer Tools · head to head

Atlantis vs Microsoft Sentinel

Atlantis logo

Atlantis

Developer Tools

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

From
Free
Free plan
Yes
Full reviewWebsite
Microsoft Sentinel logo

Microsoft Sentinel

Cybersecurity

Cloud-native SIEM and SOAR solution

From
Free
Free plan
Yes
Full reviewWebsite

The short version

  • 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.; Microsoft Sentinel billing is driven by the volume of log data ingested per day, so cost scales with log noise rather than with users or protected assets
  • They diverge on capability: Atlantis covers Pull request plans, Microsoft Sentinel covers AI-powered analytics.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Atlantis and Microsoft Sentinel actually diverge.

Attributes where Atlantis and Microsoft Sentinel differ
AttributeAtlantisMicrosoft Sentinel
Pricing modelOpen source, no licence feeusage-based
PlatformsLinux, Docker, Kubernetes, Self-hostedWeb, Api
CategoryDeveloper ToolsCybersecurity
FoundedUnknown1975

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 Atlantis

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

Only in Microsoft Sentinel

  • AI-powered analytics
  • Fusion detection
  • UEBA
  • Automated response playbooks
  • Threat intelligence
  • Hunting queries
  • Workbooks
  • Incident management

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 Microsoft Sentinel
  • Removing local applies and the credential sprawl that comes with every engineer holding production keysnot Microsoft Sentinel
  • Getting pull request driven infrastructure without paying a per-user subscription for a hosted platformnot Microsoft Sentinel
  • Enforcing Conftest policies as a blocking check before an apply can runnot Microsoft Sentinel

Microsoft Sentinel

  • Cloud-based security information and event management (SIEM)not Atlantis
  • Extended detection and response (XDR) across enterprise infrastructurenot Atlantis
  • Data ingestion and long-term security analyticsnot 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.

Microsoft Sentinel

  • Billing is driven by the volume of log data ingested per day, so cost scales with log noise rather than with users or protected assets
  • Commitment tier discounts require reserving daily ingestion capacity in advance, and a tier cannot be downgraded until 31 days have passed
  • Commitment tiers start at 100 GB per day, above what smaller estates ingest
  • Charges for Log Analytics, Logic Apps and Machine Learning are billed separately on top of Sentinel itself
  • The free allowance is only up to 5 MB per user per day for selected Microsoft 365 security logs
  • Promotional commitment pricing is time limited and locks in only until a stated end date

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

Microsoft Sentinel

Free
  • Pay-As-You-Go$2.46/day
    • Per GB ingested
    • 90-day retention
    • First 31 days free for new workspaces
  • Commitment TiersFree
    • 100GB to 50TB tiers
    • Up to 65% discount
    • Predictable billing
  • Microsoft 365 E5Free
    • Free data ingestion for M365 logs
    • Bundled with E5 license

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 Microsoft Sentinel if

  • You need ai-powered analytics.
  • You want to start without paying.
  • You work on Web, Api.
  • You also want fusion detection.
Microsoft Sentinel review

Questions people ask

Is Atlantis or Microsoft Sentinel better?
Neither clearly leads. Atlantis starts at Free and Microsoft Sentinel at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Atlantis or Microsoft Sentinel?
Atlantis starts at Free and Microsoft Sentinel at Free.
Does Atlantis or Microsoft Sentinel run on more platforms?
Atlantis runs on Linux, Docker, Kubernetes, Self-hosted. Microsoft Sentinel runs on Web, Api.
Can I use Atlantis for free?
Both have a free tier, so you can try either at no cost before committing.
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 Microsoft Sentinel is typically brought in for.
What can Atlantis do that Microsoft Sentinel cannot?
Atlantis covers Pull request plans, Comment driven apply, Workspace locking, Policy checking. Microsoft Sentinel covers AI-powered analytics, Fusion detection, UEBA, Automated response playbooks.

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.

Microsoft Sentinel: How is Microsoft Sentinel pricing calculated?

Microsoft Sentinel uses a pay-as-you-go usage-based model where you pay only for data ingested, stored, and consumed. Flexible commitment tiers are available to reduce total cost of ownership, with specific rates not published on the public pricing page. Source: https://www.microsoft.com/security/business/siem-and-xdr/microsoft-sentinel/

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.

Microsoft Sentinel: Does Microsoft Sentinel require an Azure subscription?

Yes, Microsoft Sentinel requires a Microsoft Azure subscription to operate. Pricing is handled through Azure and varies based on data consumption and the commitment tier you select. Source: https://www.microsoft.com/security/business/siem-and-xdr/microsoft-sentinel/

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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