Databases · head to head
Convex vs DataStax
Convex
Databases
Reactive backend combining a document database, TypeScript server functions and live queries, source-available under the Functional Source Licence.
- From
- Free
- Rated
- -
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.; DataStax dataStax's own Astra DB documentation states the Enterprise plan is an annual, contract-based plan with negotiated pricing, meaning list prices are not published for that tier
- They diverge on capability: Convex covers Reactive queries, DataStax covers Cassandra Compatible.
- Prices and features above were last checked on 30 August 2026.
Where they differ
Only the attributes on which Convex and DataStax actually diverge.
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 DataStax
- Cassandra Compatible
- Vector Search
- Serverless
- Multi-cloud
- Streaming
- CDC
- GraphQL API
- LangChain
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 DataStax
- Agent backends that need durable state, scheduled work and transactional writes without assembling a queue, a database and a cachenot DataStax
- Small product teams who need a complete backend, including auth integration, file storage and subscriptions, without hiring infrastructure engineersnot DataStax
- Prototypes that must become production without a rewrite of the data layer, where end-to-end TypeScript types remove a class of integration bugsnot DataStax
DataStax
- 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.
DataStax
- DataStax's own Astra DB documentation states the Enterprise plan is an annual, contract-based plan with negotiated pricing, meaning list prices are not published for that tier
- DataStax's Astra DB documentation directs Standard plan customers to IBM's watsonx.data pricing for exact consumption-based rates following the DataStax/IBM deal, rather than publishing them on DataStax's own site
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
DataStax
Free- FreeFree
- 5GB storage
- 40M read/write ops
- Vector search
- Pay As You GoFree
- Usage-based pricing
- Multi-region
- Enterprise support
Which should you pick?
Choose Convex if
- You need reactive queries.
- You want to start without paying.
- You also want typescript server functions.
Choose DataStax if
- You need cassandra compatible.
- You want to start without paying.
- You work on Web, Aws, Azure, Gcp.
- You also want vector search.
Questions people ask
- Is Convex or DataStax better?
- Neither clearly leads. Convex starts at Free and DataStax at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
- Which is cheaper, Convex or DataStax?
- Convex starts at Free and DataStax at Free.
- Does Convex or DataStax run on more platforms?
- Convex runs on Web. DataStax runs on Web, Aws, Azure, Gcp.
- 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 DataStax is typically brought in for.
- What can Convex do that DataStax cannot?
- Convex covers Reactive queries, TypeScript server functions, ACID transactions, Document database. DataStax covers Cassandra Compatible, Vector Search, Serverless, Multi-cloud.
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.
DataStax: Is DataStax available as a managed service?
Yes, DataStax is available as Astra DB, a managed database service. Users can sign up for Astra DB directly to create accounts and access the platform.
SourceConvex: 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.
DataStax: How is DataStax priced?
DataStax (now part of IBM) does not publish pricing on its documentation homepage. Pricing information would need to be obtained through the Astra DB signup page or by contacting IBM directly.
SourceConvex: 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.
DataStax: Is there an enterprise licensing option?
DataStax is now part of IBM. Enterprise customers should contact IBM directly for licensing agreements and enterprise-specific pricing.
SourceConvex: 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.
DataStax: Can I try DataStax without an account?
To use DataStax Astra DB, account creation is required. The documentation does not mention a free trial or demonstration environment that does not require signup.
SourceConvex: 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.
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