Softwr

Databases · head to head

Convex vs ScyllaDB

Convex logo

Convex

Databases

Reactive backend combining a document database, TypeScript server functions and live queries, source-available under the Functional Source Licence.

From
Free
Rated
-
Full reviewWebsite
ScyllaDB logo

ScyllaDB

Databases

The real-time big data database compatible with Cassandra

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Convex the Functional Source Licence is not an OSI open source licence: competing use is prohibited until each release reaches its second anniversary and converts to Apache 2.0, so you may self-host but you may not build a service on it.; ScyllaDB enterprise tier requires custom quote from sales
  • They diverge on capability: Convex covers Reactive queries, ScyllaDB covers Cassandra Compatible.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Convex and ScyllaDB actually diverge.

Attributes where Convex and ScyllaDB differ
AttributeConvexScyllaDB
Pricing modelsubscriptionusage-based
PlatformsWebLinux, Docker, Kubernetes, Web
FoundedUnknown2015

Identical on both: starting price (Free), 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 Convex

  • Reactive queries
  • TypeScript server functions
  • ACID transactions
  • Document database
  • Scheduling and workflows
  • File storage
  • Text and vector search
  • End-to-end types

Only in ScyllaDB

  • Cassandra Compatible
  • DynamoDB Compatible
  • 10x Throughput
  • Low Latency
  • Auto-tuning
  • Lightweight Transactions
  • Change Data Capture
  • Cassandra Drivers

What people use each for

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

Convex

  • Collaborative applications where several users see the same data and every client must reflect a change immediatelynot ScyllaDB
  • Agent backends that need durable state, scheduled work and transactional writes without assembling a queue, a database and a cachenot ScyllaDB
  • Small product teams who need a complete backend, including auth integration, file storage and subscriptions, without hiring infrastructure engineersnot ScyllaDB
  • Prototypes that must become production without a rewrite of the data layer, where end-to-end TypeScript types remove a class of integration bugsnot ScyllaDB

ScyllaDB

  • Real-time applicationsnot Convex
  • Content managementnot Convex
  • User profilesnot Convex
  • Mobile backendsnot Convex
  • Cachingnot Convex

Where each one falls short

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

Convex

  • The Functional Source Licence is not an OSI open source licence: competing use is prohibited until each release reaches its second anniversary and converts to Apache 2.0, so you may self-host but you may not build a service on it.
  • Transactions are bounded at one second of user code, 16 MiB read and written, 32,000 documents scanned and 16,000 written, so every backfill, migration or bulk import has to be chunked into scheduled batches rather than written as a single operation.
  • There is no SQL and no query planner; you declare up to 32 indexes per table and traverse them, and joins are loops in TypeScript, so an unanticipated access pattern requires a schema and index change rather than a new query.
  • It is not an analytical database, so reporting means streaming data out to a warehouse and BI tools cannot be pointed at Convex directly, which adds a pipeline the architecture diagram did not originally include.
  • The application is written against Convex's function and client APIs rather than a standard protocol, so leaving means rewriting the data access layer and replacing the reactivity model, not repointing a connection string.

ScyllaDB

  • Enterprise tier requires custom quote from sales
  • Pricing varies by cloud provider, storage, and instance configuration
  • Contracts available but commitment required for subscription discounts

Pricing, plan by plan

Convex

Free
  • Free & StarterFree
    • Supports 1-6 developers
    • Reactive database
    • File storage
  • Professional$25/month per developer
    • Supports up to 20 developers
    • All Starter features
    • Log streaming
  • Business & Enterprise$2500/month minimum
    • Supports 50+ developers
    • SAML/SSO
    • Service SLAs

ScyllaDB

Free
  • ScyllaDB Cloud Standard$null/variable
    • Usage-based billing: vCPU, RAM, NVMe SSD storage
    • 2-hour P1 support response time
    • 99.9% uptime SLA
  • ScyllaDB Cloud Professional$null/variable
    • Enterprise-grade scalability
    • 1-hour P1 support response
    • Enhanced features included
  • ScyllaDB Cloud Premium$null/variable
    • Custom security and networking
    • 15-minute P1 support response
    • 99.99% uptime SLA
  • ScyllaDB Enterprise$null/quote
    • Self-managed deployment
    • On-premise or private cloud
    • Custom quote required

Which should you pick?

Choose Convex if

  • You need reactive queries.
  • You want to start without paying.
  • You also want typescript server functions.
Convex review

Choose ScyllaDB if

  • You need cassandra compatible.
  • You want to start without paying.
  • You work on Linux, Docker, Kubernetes, Web.
  • You also want dynamodb compatible.
ScyllaDB review

Questions people ask

Is Convex or ScyllaDB better?
Neither clearly leads. Convex starts at Free and ScyllaDB at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Convex or ScyllaDB?
Convex starts at Free and ScyllaDB at Free.
Does Convex or ScyllaDB run on more platforms?
Convex runs on Web. ScyllaDB runs on Linux, Docker, Kubernetes, Web.
Can I use Convex for free?
Both have a free tier, so you can try either at no cost before committing.
What is Convex best used for?
Convex is most often used for collaborative applications where several users see the same data and every client must reflect a change immediately, agent backends that need durable state, scheduled work and transactional writes without assembling a queue, a database and a cache, small product teams who need a complete backend, including auth integration, file storage and subscriptions, without hiring infrastructure engineers, prototypes that must become production without a rewrite of the data layer, where end-to-end typescript types remove a class of integration bugs. Of those, collaborative applications where several users see the same data and every client must reflect a change immediately and agent backends that need durable state, scheduled work and transactional writes without assembling a queue, a database and a cache are not what ScyllaDB is typically brought in for.
What can Convex do that ScyllaDB cannot?
Convex covers Reactive queries, TypeScript server functions, ACID transactions, Document database. ScyllaDB covers Cassandra Compatible, DynamoDB Compatible, 10x Throughput, Low Latency.

Answered from the vendors’ own pages

Convex: Is Convex open source?

It is source-available under FSL-1.1-Apache-2.0. You may read, modify and self-host it, but competing use is prohibited until each release converts to Apache 2.0 on its second anniversary.

ScyllaDB: How is ScyllaDB Cloud pricing calculated?

ScyllaDB Cloud uses transparent, resource-based billing based on instance type (vCPU and RAM), NVMe SSD storage, service plan tier, deployment model, and cloud provider costs.

Source
Convex: Can I self-host it?

Yes. The backend, dashboard and CLI can run on your own infrastructure, with most of the features of the cloud product. Self-hosted instances include a telemetry beacon that can be disabled.

ScyllaDB: Does ScyllaDB offer a free trial?

ScyllaDB offers a 30-day developer trial on smaller instances and a 48-hour production evaluation trial with full-grade instances.

Source
Convex: Does it support SQL?

No. Data is accessed through a TypeScript query builder over declared indexes. Relationships are traversed in code, which is explicit and type-safe but means no ad hoc querying.

ScyllaDB: What cost savings are available for long-term ScyllaDB commitments?

ScyllaDB subscription contracts provide up to 70% or more in savings compared to on-demand hourly billing. 1-year and 3-year contract options are available.

Source
Convex: What happens if a mutation exceeds the limits?

It fails rather than running longer, so bulk work must be split into batches and scheduled. The limits are per transaction: one second of user code, 16 MiB read and written, 32,000 documents scanned and 16,000 written.

ScyllaDB: How much cheaper is ScyllaDB than DynamoDB?

Unlike DynamoDB which charges per read/write unit, ScyllaDB charges based on resource usage only, potentially delivering 50% or greater cost reduction for high-throughput workloads.

Source
Convex: How does reactivity actually work?

Queries are deterministic functions and Convex records the data each one read. When a mutation changes that data, affected queries are re-run and subscribed clients receive the new result, so cache invalidation is handled by the platform.

Share

Related pages

More on Convex

More on ScyllaDB

Keep looking

Other head to heads