Debezium is the open-source CDC engine that pioneered exactly-once log-based replication. We grew up using it. Here's a technical, honest comparison - including where Debezium is still the right answer.
If you're a small team running a single Postgres → Kafka pipeline and you have Kafka Connect expertise on staff, Debezium is fine. If you have more than three connectors, multiple sinks, and an on-call rotation that hates pages, Zipline does the same job with roughly an order of magnitude less ops burden.
| Capability | Zipline | Debezium |
|---|---|---|
| Exactly-once delivery | Default, end-to-end | Source-side; sink semantics depend on Kafka Connect connector |
| Throughput, single node | 2.1M events/sec on m5.4xlarge | ~180K events/sec, equivalent broker config |
| P50 latency, source → sink | 142ms | 1.5–4s, depending on Connect tuning |
| Cluster required to start | No - single binary | Kafka + Connect cluster, ZK or KRaft |
| Connector catalog | 60 sources + sinks, first-party | ~12 sources; sinks via Kafka Connect community |
| Data leaves your VPC | No - runs in your infrastructure | No (self-hosted) / Yes (managed offerings) |
| Schema evolution | Auto, with compatibility modes | Source-side; sink reconciliation manual |
| Replay / time travel | Built-in, any window | Manual, by re-reading WAL |
| CLI deploy time | 30 seconds | Cluster setup is hours; pipeline definition minutes |
| License | Apache 2.0 SDK + closed-source service plane | Apache 2.0 (entirely) |
| Cost at 100M events/day | $150/month (Team) | $0 license + $1.5–3K/month in cluster costs |
In our published benchmark (Postgres → Kafka, 1KB events, exactly-once), Zipline sustained 2.1M events/sec on a single m5.4xlarge while Debezium + Kafka Connect peaked at ~180K under equivalent broker config. The difference comes from a custom log reader and a non-Java runtime - Debezium's JVM overhead and Connect's task model are the bottleneck.
2.1M evt/s · single node · no cluster · benchmark linked from /observability.
~180K evt/s with Kafka Connect; scales by adding tasks, but coordination cost grows quickly past 1M/s.
Both tools provide exactly-once at the source. The difference is end-to-end. Debezium hands events to Kafka, but the sink connector - JDBC, Snowflake, BigQuery - has its own delivery semantics. In practice, you stitch idempotency together with deduplication keys at the sink. Zipline owns both ends and treats exactly-once as a single property.
Debezium's hardest problem isn't Debezium - it's running Kafka Connect at scale. Connect's rebalance model, offset commits, dead-letter queues, and JVM tuning are well-known sharp edges. Zipline ships as a single Go binary that runs in your VPC. No cluster, no ZK, no Connect framework.
One process. Health endpoint. Prometheus metrics. The ops surface fits in your head.
Kafka cluster + Connect workers + schema registry + your DLQ strategy. Powerful, but it's an architecture, not a tool.
If you already run Kafka and have Connect operators on payroll, Debezium adds zero net infrastructure. If you need fully open-source from end to end (no closed service plane), Debezium is honest about that and Zipline isn't. And if you're streaming from a source we don't support yet, Debezium's plugin ecosystem is broader.
We provide a free migration helper that reads your Debezium config and outputs the equivalent Zipline pipeline YAML. Engineers run it, eyeball the diff, and ship.