Softwr

Databases · head to head

CosmosDB vs MotherDuck

CosmosDB logo

CosmosDB

Databases

Globally distributed, multi-model database service from Azure

From
Free
Rated
-
Full reviewWebsite
MotherDuck logo

MotherDuck

Databases

Serverless analytics data warehouse built on DuckDB

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: CosmosDB autoscale provisioned throughput enforces a minimum of 1,000 RU/s, billed hourly whether or not the database is used; MotherDuck the free Lite plan caps compute at 10 hours per month, which limits it to light or hobbyist workloads.
  • They diverge on capability: CosmosDB covers Global Distribution, MotherDuck covers Serverless DuckDB instances.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which CosmosDB and MotherDuck actually diverge.

Attributes where CosmosDB and MotherDuck differ
AttributeCosmosDBMotherDuck
PlatformsWeb, Azureweb, api
Founded19752022

Identical on both: starting price (Free), pricing model (usage-based), free tier (Yes), user rating (Not yet rated), category (Databases).

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 CosmosDB

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

Only in MotherDuck

  • Serverless DuckDB instances
  • Cloud storage querying
  • MCP server
  • Dives
  • Flights
  • Read-scaling replicas

What people use each for

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

CosmosDB

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

MotherDuck

  • Ad-hoc analytics on gigabyte-to-terabyte datasetsnot CosmosDB
  • Querying data lake files in S3/GCS/Azure without ingestionnot CosmosDB
  • AI agent data analysis via MCPnot CosmosDB
  • Scheduled data pipeline transformationsnot CosmosDB

Where each one falls short

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

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

MotherDuck

  • The free Lite plan caps compute at 10 hours per month, which limits it to light or hobbyist workloads.
  • Business plan usage charges on top of the $250/month base can make costs less predictable than flat-rate competitors.
  • There are no academic or non-profit discounts, unlike some competing data platforms.
  • Annual billing requires going through a sales conversation rather than a self-serve toggle.

Pricing, plan by plan

CosmosDB

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

MotherDuck

Free
  • LiteFree
    • Up to 3 internal active users
    • 2 service accounts
    • 10GB free storage
  • Business$250/month
    • Up to 10 internal active users
    • Unlimited service accounts
    • 5 instance types with read-scaling replicas
  • Enterprise$undefined/month
    • Unlimited internal users and service accounts
    • Fixed-cost capacity pricing
    • AWS PrivateLink, IP allowlisting

Which should you pick?

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

Choose MotherDuck if

  • You need serverless duckdb instances.
  • You want to start without paying.
  • You work on web, api.
  • You also want cloud storage querying.
MotherDuck review

Questions people ask

Is CosmosDB or MotherDuck better?
Neither clearly leads. CosmosDB starts at Free and MotherDuck at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, CosmosDB or MotherDuck?
CosmosDB starts at Free and MotherDuck at Free.
Does CosmosDB or MotherDuck run on more platforms?
CosmosDB runs on Web, Azure. MotherDuck runs on web, api.
Can I use CosmosDB for free?
Both have a free tier, so you can try either at no cost before committing.
What is CosmosDB best used for?
CosmosDB is most often used for running a globally distributed multi model database on azure, serving low latency reads and writes from multiple azure regions, storing document, key value and graph data behind a managed service. Of those, running a globally distributed multi model database on azure and serving low latency reads and writes from multiple azure regions are not what MotherDuck is typically brought in for.
What can CosmosDB do that MotherDuck cannot?
CosmosDB covers Global Distribution, Multi-model APIs, Elastic Scaling, Five Consistency Levels. MotherDuck covers Serverless DuckDB instances, Cloud storage querying, MCP server, Dives.

Answered from the vendors’ own pages

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
MotherDuck: What does MotherDuck cost?

The Lite plan is free (up to 3 users, 10GB storage, 10 hours of Pulse compute/month). Business is $250/organization/month plus usage, with Enterprise available at custom fixed-cost pricing.

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
MotherDuck: Is there a free plan and what are its limits?

Yes, the Lite plan is free for up to 3 internal active users and 2 service accounts, with 10GB of storage and 10 hours of Pulse compute per month.

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
MotherDuck: How is usage metered?

Compute instances (Pulse, Standard, Jumbo, Mega, Giga) are billed per second at hourly rates from $0.60 to $24.00/hour, storage is $0.04/GB-month, and AI Functions cost $1.00 per AI Unit.

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
Share

Related pages

More on CosmosDB

More on MotherDuck

Keep looking

Other head to heads