What you actually have to run
If you have Kafka and a job that fits on one machine, these are your real alternatives. Deployment shape only. For our delivery guarantee, the harness that proves it.
| Ubik | Kafka Streams | Proton | Flink | |
|---|---|---|---|---|
| What you run | one process, or a library inside yours | a library inside your JVM app | a server | a JobManager and TaskManagers |
| Query language | SQL | Java or Kotlin | SQL | SQL or Java |
| Where window state lives | one local file | RocksDB, plus a changelog topic in your broker | server-local | RocksDB, plus a checkpoint store |
| Embed in your own process | yes, C ABI, any language | JVM only | no | no |
| Runtime dependencies | libc and libstdc++ | a JVM | a server | a JVM and a cluster |
What Ubik is not
Not a Flink replacement at hyperscale
Above a few million events/s sustained, state beyond one machine’s NVMe, or hot-state sub-second failover, that is Flink territory.
Not a message broker
It reads and writes logs, it never becomes the log of record. You bring the durable Kafka-shaped thing upstream. Rebuilding one is out of scope.
Not append-and-correct
Windows close on the watermark and emit once: no retractions, no late corrections downstream. Two streams join only on an equi key plus a bounded time band; anything unbanded is refused at plan time rather than accumulating state without bound. No Protobuf. That disqualifies some workloads.
Not a distributed system
No distributed code path will ever land in the core. A second machine would make it the thing it replaces.
What the cluster costs you in cash
Confluent Cloud for Apache Flink publishes $0.21 per CFU-hour. A statement consumes at least one unit, and a stateful windowed job usually more. One unit running continuously for a year is $1 840, the documented floor. That is stream-processing compute alone, before the Kafka cluster and data transfer.
Three modest continuous jobs at that floor is roughly $5 500 a year and climbs with every job you add. Self-managing Flink instead moves the cost from an invoice to a salary line.
Ubik Team is $1,200/yr for up to ten production instances, on machines you already have, with no usage-based licence fees. Infrastructure costs are separate. There is no per-job cost, because there is no control plane charging for one.
Run the division against your own usage. If you pay for stream-processing compute today, that number is on an invoice you already have.
Rate as published by the vendor, A statement consumes at least one CFU and a stateful windowed job usually consumes more, so this is the documented floor. Flink compute only: the Kafka cluster and data transfer are billed separately.