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Databases · head to head

Azure SQL vs CosmosDB

Azure SQL logo

Azure SQL

Databases

Intelligent, scalable cloud database service from Microsoft

From
Free
Rated
-
Full reviewWebsite
CosmosDB logo

CosmosDB

Databases

Globally distributed, multi-model database service from Azure

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Azure SQL ecosystem lock-in limits flexibility compared to open-source or multi-cloud solutions; CosmosDB autoscale provisioned throughput enforces a minimum of 1,000 RU/s, billed hourly whether or not the database is used
  • They diverge on capability: Azure SQL covers Intelligent Performance, CosmosDB covers Global Distribution.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Azure SQL and CosmosDB actually diverge.

Attributes where Azure SQL and CosmosDB differ
AttributeAzure SQLCosmosDB
Pricing modelUnknownusage-based
PlatformsCloud (Microsoft Azure)Web, Azure

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Databases), founded (1975).

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 Azure SQL

  • Intelligent Performance
  • Advanced Security
  • Hyperscale
  • Serverless Compute
  • Geo-replication
  • Automatic Tuning
  • Built-in AI
  • Data Factory

Only in CosmosDB

  • Global Distribution
  • Multi-model APIs
  • Elastic Scaling
  • Five Consistency Levels
  • SLA-backed Latency
  • Automatic Indexing
  • Serverless
  • Stream Analytics

Both cover

  • Power BI
  • Azure Functions
  • Logic Apps
  • Web support
  • Azure support

What people use each for

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

Azure SQL

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

CosmosDB

  • Running a globally distributed multi model database on Azurenot Azure SQL
  • Serving low latency reads and writes from multiple Azure regionsnot Azure SQL
  • Storing document, key value and graph data behind a managed servicenot Azure SQL

Where each one falls short

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

Azure SQL

  • Ecosystem lock-in limits flexibility compared to open-source or multi-cloud solutions
  • Managed service reduces control over database configuration and optimization tuning
  • Pricing complexity with consumption-based model can be unpredictable at scale
  • Less operational depth compared to Amazon RDS for advanced scaling scenarios
  • Azure PostgreSQL is less compelling than dedicated PostgreSQL providers outside Azure ecosystem

CosmosDB

  • Autoscale provisioned throughput enforces a minimum of 1,000 RU/s, billed hourly whether or not the database is used
  • Provisioned throughput is charged in every region the account is replicated to, so multi region accounts multiply the RU bill
  • Storage charges cover data, indexes and backups in each replicated region
  • Egress out of Azure and between regions is charged, though ingress is free
  • The free allowance is one account per Azure subscription, limited to 1,000 RU/s and 25 GB
  • RU/s rates vary by region and are only shown through the pricing calculator rather than a flat published rate

Pricing, plan by plan

Azure SQL

Free

No published plan breakdown. See the Azure SQL review.

CosmosDB

Free
  • Free TierFree
    • 1000 RU/s
    • 25GB storage
    • First 12 months
  • ServerlessFree
    • Pay per request
    • Auto-scaling
    • Event-driven workloads

Which should you pick?

Choose Azure SQL if

  • You need intelligent performance.
  • You want to start without paying.
  • You work on Cloud (Microsoft Azure).
  • You also want advanced security.
Azure SQL review

Choose CosmosDB if

  • You need global distribution.
  • You want to start without paying.
  • You work on Web, Azure.
  • You also want multi-model apis.
CosmosDB review

Questions people ask

Is Azure SQL or CosmosDB better?
Neither clearly leads. Azure SQL starts at Free and CosmosDB at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Azure SQL or CosmosDB?
Azure SQL starts at Free and CosmosDB at Free.
Does Azure SQL or CosmosDB run on more platforms?
Azure SQL runs on Cloud (Microsoft Azure). CosmosDB runs on Web, Azure.
Can I use Azure SQL for free?
Both have a free tier, so you can try either at no cost before committing.
What is Azure SQL best used for?
Azure SQL is most often used for transaction processing, data storage, application backend, reporting. Of those, transaction processing and data storage are not what CosmosDB is typically brought in for.
What can Azure SQL do that CosmosDB cannot?
Azure SQL covers Intelligent Performance, Advanced Security, Hyperscale, Serverless Compute. CosmosDB covers Global Distribution, Multi-model APIs, Elastic Scaling, Five Consistency Levels. Both handle Power BI, Azure Functions, Logic Apps, Web support.

Answered from the vendors’ own pages

Azure SQL: Does Azure SQL Database offer a free tier?

Yes, Azure SQL Database includes a permanent free tier that provides 100,000 vCore seconds, 32 GB of data storage, and 32 GB of backup storage per month. This free tier is available for the lifetime of any Azure subscription with no expiration.

Source
CosmosDB: Is there a free tier for Azure Cosmos DB?

Yes, Cosmos DB offers a free tier with 1,000 RU/s of throughput and 25 GB of storage per month for the lifetime of the account, available to new accounts.

Source
Azure SQL: What pricing models does Azure SQL Database support?

Azure SQL Database offers consumption-based pricing where you pay for resources used, with no long-term commitments required. Database Savings Plans launched in March 2026 allow committing to a fixed hourly amount and save up to 35% across Azure database services.

Source
CosmosDB: How is Cosmos DB priced after the free tier?

Cosmos DB uses three billing models: provisioned throughput billed per request unit per second, vCore pricing for certain APIs, or serverless consumption pricing where you pay only for requests processed. Reserved capacity offers 20% discount for one year or 30% for three years.

Source
Azure SQL: Is Azure SQL Database compatible with on-premises SQL Server?

Yes, Azure SQL Database shares the same Database Engine as on-premises SQL Server. Existing databases maintain their compatibility level and continue to work after upgrades. Azure SQL Managed Instance provides even broader SQL Server compatibility dating back to SQL Server 2008.

Source
CosmosDB: Can I change my pricing model after choosing one?

No. Once you select a compute pricing model and API, they cannot be changed. This choice is permanent for that database.

Source
Azure SQL: What high availability features does Azure SQL Database provide?

Azure SQL Database provides automatic backups, geo-replication for disaster recovery, failover groups for automatic failover, and zone redundancy for enhanced availability. The service maintains a 99.99% availability SLA for Business Critical tier.

Source
CosmosDB: Is there a trial period for Cosmos DB beyond the free tier?

Azure offers a 30-day free trial account for all Azure services. Additionally, Azure AI customers may be eligible for a 90-day free Cosmos DB subscription through the Azure AI Advantage program.

Source
Azure SQL: Can I use AI features with Azure SQL Database?

Yes, Azure SQL Database includes Copilot for database tasks, Intelligent Applications support, REST API endpoints for building applications, and GraphQL endpoints for modern app development.

Source
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