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Databases · head to head

Aiven vs CosmosDB

Aiven logo

Aiven

Databases

Fully managed open source data infrastructure cloud

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: Aiven the free plan gives 1 VM with 1 CPU, 1 GB RAM and 1 GB storage, and cannot pick a specific cloud or region; 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: Aiven covers Multi-cloud Support, CosmosDB covers Global Distribution.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Aiven and CosmosDB actually diverge.

Attributes where Aiven and CosmosDB differ
AttributeAivenCosmosDB
PlatformsWeb, Aws, Azure, Gcp, DoWeb, Azure
Founded20161975

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 Aiven

  • Multi-cloud Support
  • Automated Backups
  • Seamless Upgrades
  • VPC Peering
  • End-to-end Encryption
  • Compliance
  • Observability
  • PostgreSQL

Only in CosmosDB

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

Both cover

  • Web support
  • Azure support

What people use each for

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

Aiven

  • Running managed open source databases without operating themnot CosmosDB
  • Multi-cloud deployment across AWS, Google Cloud, Azure, DigitalOcean, OVH and UpCloudnot CosmosDB
  • Highly available data services with automatic failovernot CosmosDB
  • Prototyping on a small free instance before scaling upnot CosmosDB

CosmosDB

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

Where each one falls short

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

Aiven

  • The free plan gives 1 VM with 1 CPU, 1 GB RAM and 1 GB storage, and cannot pick a specific cloud or region
  • Free and Developer tiers have no integrations and no connection pooling
  • Connection pooling, database forks and dynamic disk sizing need the Business or Premium plan
  • A 99.99 percent uptime SLA starts at the Startup plan from $75 a month
  • High availability with automatic failover starts at Business from $180 a month

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

Aiven

Free
  • Free TrialFree
    • $300 credits
    • 30 day trial
    • All services
  • Startup$19/month
    • Single node
    • Basic support
    • Daily backups

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 Aiven if

  • You need multi-cloud support.
  • You want to start without paying.
  • You work on Web, Aws, Azure, Gcp, Do.
  • You also want automated backups.
Aiven 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 Aiven or CosmosDB better?
Neither clearly leads. Aiven 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, Aiven or CosmosDB?
Aiven starts at Free and CosmosDB at Free.
Does Aiven or CosmosDB run on more platforms?
Aiven runs on Web, Aws, Azure, Gcp, Do. CosmosDB runs on Web, Azure.
Can I use Aiven for free?
Both have a free tier, so you can try either at no cost before committing.
What is Aiven best used for?
Aiven is most often used for running managed open source databases without operating them, multi-cloud deployment across aws, google cloud, azure, digitalocean, ovh and upcloud, highly available data services with automatic failover, prototyping on a small free instance before scaling up. Of those, running managed open source databases without operating them and multi-cloud deployment across aws, google cloud, azure, digitalocean, ovh and upcloud are not what CosmosDB is typically brought in for.
What can Aiven do that CosmosDB cannot?
Aiven covers Multi-cloud Support, Automated Backups, Seamless Upgrades, VPC Peering. CosmosDB covers Global Distribution, Multi-model APIs, Elastic Scaling, Five Consistency Levels. Both handle Web support, Azure support.

Answered from the vendors’ own pages

Aiven: What does Aiven's free tier include and does it have any time limit?

The free tier includes PostgreSQL with 1 VM, 1 CPU, 1 GB RAM, and 1 GB storage with access to limited cloud and region selections. There are no time limitations on the free tier, though Aiven reserves the right to shut down accounts that violate policies or remain unused for extended periods.

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
Aiven: How is Aiven billed and what are the monthly costs for each tier?

Aiven bills services by the hour and invoices monthly, charging only for what you actually run. PostgreSQL pricing starts at 5 dollars per month for Developer, 12 dollars per month for Hobbyist, 75 dollars per month for Startup, 180 dollars per month for Business, and 270 dollars per month for Premium. All paid tiers offer hourly billing options as well.

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
Aiven: What backup retention periods are included at different Aiven tiers?

Backup retention increases with tier level: Startup tier provides 2 days of backup retention, Business tier offers 14 days, and Premium tier includes 30 days. Point-in-time restore is available on all paid tiers.

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
Aiven: Is high availability included in Aiven pricing or charged separately?

High availability, backups, and routine maintenance are all included in the tier costs with no separate charges. The Business tier includes 2 VMs with automatic failover, and Premium includes 3 VMs with a second standby node.

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
Aiven: Does Aiven offer a trial period to test premium features?

Aiven offers a 30-day free trial to access premium features beyond what the free plan provides.

Source
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