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Keycloak vs Microsoft SQL Server

Keycloak logo

Keycloak

Developer Tools

Open-source identity and access management server.

From
Free
Free plan
Yes
Visit KeycloakFull review
Microsoft SQL Server logo

Microsoft SQL Server

Databases

Enterprise-grade relational database management system

From
Free
Free plan
Yes
Visit Microsoft SQL ServerFull review

The short version

  • Keycloak is an open-source IAM platform supporting OpenID Connect, OAuth 2; Microsoft SQL Server is a relational database management system.
  • Keycloak is free; Microsoft SQL Server starts at $3945/mo.
  • Where Keycloak falls short: requires self-hosted deployment and operational expertise to install, configure and maintain.
  • Where Microsoft SQL Server falls short: performance monitoring toolset is insufficient for hybrid cloud environments requiring real-time analytics across multiple deployment types.
  • Prices and features on this page were last checked on 13 November 2026.

Where they differ

Only the attributes on which Keycloak and Microsoft SQL Server actually diverge.

Attributes where Keycloak and Microsoft SQL Server differ
AttributeKeycloakMicrosoft SQL Server
PlatformsSelf-hosted, Linux, Windows, APIWindows, Linux, Self-hosted, Azure
CategoryDeveloper ToolsDatabases

Identical on both: starting price (Free), free tier (Yes).

Not yet recorded: pricing model for Microsoft SQL Server, founded for Keycloak.

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 Keycloak

Nothing recorded that Microsoft SQL Server does not also cover.

Only in Microsoft SQL Server

  • T-SQL
  • ACID Compliance
  • Advanced Security
  • In-memory OLTP
  • Columnstore Indexes
  • Always On Availability
  • Machine Learning Services
  • Azure

What people use each for

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

Keycloak

  • Organisations requiring self-hosted identity infrastructure for compliance or data residencynot Microsoft SQL Server
  • Companies with existing LDAP/Active Directory systems needing federated authenticationnot Microsoft SQL Server
  • Open-source projects and communities requiring free IAM without licensing costsnot Microsoft SQL Server
  • Enterprises building custom identity workflows requiring fine-grained authorisationnot Microsoft SQL Server
  • Teams with sufficient operational expertise to manage infrastructurenot Microsoft SQL Server

Microsoft SQL Server

  • Transaction processingnot Keycloak
  • Data storagenot Keycloak
  • Application backendnot Keycloak
  • Reportingnot Keycloak
  • Data analyticsnot Keycloak

Where each one falls short

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

Keycloak

  • Requires self-hosted deployment and operational expertise to install, configure and maintain
  • No managed cloud option provided by Red Hat; organisations must operate infrastructure themselves or use third-party distributions
  • Clustering and high-availability configurations require additional operational knowledge
  • Community support only; commercial support requires third-party vendors or distributions

Microsoft SQL Server

  • Licensing and on-premises deployment costs are high compared to open-source alternatives, with Enterprise Edition exceeding $60,000 for minimum core requirements
  • Performance monitoring toolset is insufficient for hybrid cloud environments requiring real-time analytics across multiple deployment types
  • Heavy I/O resource consumption can saturate disk volumes and degrade performance when processing large transaction workloads
  • Always On availability groups with up to 8 secondary replicas are limited to Enterprise edition only; Standard supports only basic availability groups with 2 replicas
  • CPU and memory scaling is capped at 4 sockets or 32 cores on Standard edition, limiting deployments requiring higher compute capacity

Pricing, plan by plan

Keycloak

Free
  • Open-sourceFree
    • Full platform functionality
    • Self-hosted deployment
    • Community support

Microsoft SQL Server

Free
  • ExpressFree
    • 4 cores maximum
    • 1.4 GB memory per instance
    • 50 GB database size limit
  • DeveloperFree
    • All Enterprise features
    • Non-production use only
  • Standard$3,945
    • 32 core maximum per instance
    • 256 GB buffer pool memory
    • Basic availability groups with 2 replicas
  • Enterprise$15,123
    • Unlimited scaling
    • Always On with up to 8 secondaries
    • Advanced security and HA features

Which should you pick?

Choose Keycloak if

  • You want to start without paying.
  • You work on Self-hosted, Linux, Windows, API.
Keycloak review

Choose Microsoft SQL Server if

  • You need t-sql.
  • You want to start without paying.
  • You work on Windows, Linux, Self-hosted, Azure.
  • You also want acid compliance.
Microsoft SQL Server review

Questions people ask

Is Keycloak or Microsoft SQL Server better?
Neither clearly leads. Keycloak starts at Free and Microsoft SQL Server at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Keycloak or Microsoft SQL Server?
Keycloak starts at Free and Microsoft SQL Server at Free.
Does Keycloak or Microsoft SQL Server run on more platforms?
Keycloak runs on Self-hosted, Linux, Windows, API. Microsoft SQL Server runs on Windows, Linux, Self-hosted, Azure.
Can I use Keycloak for free?
Both have a free tier, so you can try either at no cost before committing.
What is Keycloak best used for?
Keycloak is most often used for organisations requiring self-hosted identity infrastructure for compliance or data residency, companies with existing ldap/active directory systems needing federated authentication, open-source projects and communities requiring free iam without licensing costs, enterprises building custom identity workflows requiring fine-grained authorisation. Of those, organisations requiring self-hosted identity infrastructure for compliance or data residency and companies with existing ldap/active directory systems needing federated authentication are not what Microsoft SQL Server is typically brought in for.
What can Keycloak do that Microsoft SQL Server cannot?
Microsoft SQL Server covers T-SQL, ACID Compliance, Advanced Security, In-memory OLTP.

Answered from the vendors’ own pages

Keycloak: What protocols does Keycloak support?

Keycloak supports OpenID Connect, OAuth 2.0 and SAML 2.0 protocols for authentication and authorisation.

Source
Microsoft SQL Server: What is the pricing model for SQL Server?

SQL Server uses core-based licensing with per-2-core pack pricing. Enterprise Edition costs approximately $15,123 per 2-core pack (minimum 8 cores). Standard Edition costs approximately $3,945 per 2-core pack. Developer and Express editions are free. Software Assurance adds 25-35% annually for upgrades and support.

Source
Keycloak: Can Keycloak integrate with existing user directories?

Yes. Keycloak supports user federation with LDAP and Active Directory systems, allowing organisations to leverage existing user directories.

Source
Microsoft SQL Server: Does SQL Server run on Linux?

Yes. SQL Server 2017 and later run on Linux (Red Hat Enterprise Linux, SUSE Linux Enterprise Server, Ubuntu), Docker containers, and Windows with feature parity including Always On availability groups, Active Directory authentication, and encryption.

Source
Keycloak: Is Keycloak free?

Yes. Keycloak is fully open-source and free to deploy and use. No licensing fees are required.

Source
Microsoft SQL Server: Is there a free edition of SQL Server?

Yes. SQL Server Express is free and includes all functionality of Enterprise edition for development and testing, with limits of 4 cores, 1,410 MB memory per instance, and 50 GB per database. Developer edition is also free for non-production use.

Source
Microsoft SQL Server: Can SQL Server be deployed offline?

Yes. SQL Server can be installed from offline media on machines without internet access. Microsoft provides complete offline installation packages for SQL Server, SSMS, and supporting components, making deployment in isolated or air-gapped environments feasible.

Source
Microsoft SQL Server: What high availability options does SQL Server provide?

SQL Server offers Always On availability groups (Enterprise only), Always On failover cluster instances, database mirroring, log shipping, and for disaster recovery, failover servers in Azure and Accelerated Database Recovery for faster recovery after failures.

Source
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