> ## Documentation Index
> Fetch the complete documentation index at: https://docs.doblier.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Technology Stack

> The complete software list with supported versions and decision rationale.

<Note>Single source of truth for versions — updated in the same PR as any release that changes them.</Note>

| Component            | Role                      | Supported version(s)         | Notes                                                                                                      |
| -------------------- | ------------------------- | ---------------------------- | ---------------------------------------------------------------------------------------------------------- |
| Apache Kafka         | Event backbone            | 3.x KRaft · greenfield: 4.0+ | Kafka 4.0 is KRaft-only; the newer consumer-rebalance protocol materially improves broker-failure recovery |
| Apache Flink         | Stream processing         | 2.2, RocksDB state           | Disaggregated state backend under evaluation                                                               |
| Neo4j Enterprise     | Dependency/truth graph    | 2026.02, Cypher 25           |                                                                                                            |
| ClickHouse           | Incident/event store      | 25.x                         | argMax point-in-time replay; CoalescingMergeTree an option                                                 |
| Redis Cluster        | Dedup state               | 7.x                          | Failover target \< 10s — chaos-verified per deployment, never vendor-claimed                               |
| PostgreSQL           | Suppression rules, config |                              |                                                                                                            |
| MinIO                | Object storage            |                              |                                                                                                            |
| Debezium             | Change data capture       |                              |                                                                                                            |
| Schema Registry      | Event schemas             |                              | Local schema cache serves 30 min during registry outage                                                    |
| Prometheus + Grafana | SLOs + dashboards         |                              | Multi-burn-rate windows: 5m / 1h / 6h / 30d                                                                |
| Kubernetes           | Orchestration             |                              | List supported distros & versions                                                                          |

<Warning>Vendor performance claims are not accepted as-is. Every failover/recovery figure in this stack is verified against production-sized state in [chaos testing](/orca/operations/chaos-testing) before it appears in customer-facing documentation.</Warning>

Also maintained here: base images, OS versions, TLS libraries — kept in sync with the SBOM shipped per release.