# VentStream

> Operational data streaming for change-data capture, joined projections, native WebSockets, GraphQL subscriptions, and managed engine fleets.

## Docs

- [Introduction](https://ventstream.dev/docs/introduction.md): What VentStream is, the problems it solves, and when to reach for it.
- [Install](https://ventstream.dev/docs/install.md): Download the VentStream engine and the fleet CLI
- [Quickstart](https://ventstream.dev/docs/quickstart.md): Run PostgreSQL and Neo4j CDC into OpenSearch with Docker Compose.
- [Architecture](https://ventstream.dev/docs/concepts/architecture.md): How VentStream separates engine data paths from optional Fleet management.
- [CDC & projections](https://ventstream.dev/docs/concepts/cdc-and-projections.md): How a source change becomes a denormalized document.
- [Lifecycle state](https://ventstream.dev/docs/concepts/lifecycle-phases.md): Revisioned desired state, independently reported observed state, and durable operation progress.
- [Pause, resume, and drain](https://ventstream.dev/docs/concepts/pause-resume-drain.md): Control managed engine execution without confusing queued intent with completed work.
- [Delete reconciliation](https://ventstream.dev/docs/concepts/reconciliation.md): Why a re-bootstrap can leave orphan documents, and how the engine removes them.
- [Fan-out & hot endpoints](https://ventstream.dev/docs/concepts/fan-out.md): Why one change recomputes only the right documents — and how shared lookup nodes are kept from exploding.
- [Performance](https://ventstream.dev/docs/concepts/performance.md): What drives throughput, indicative numbers, and how to measure your own.
- [Realtime brokers](https://ventstream.dev/docs/concepts/realtime-brokers.md): Choose NATS Core, NATS JetStream, or Redis Streams for native WebSocket and GraphQL subscriptions.
- [Real-time subscriptions](https://ventstream.dev/docs/concepts/real-time-subscriptions.md): Fan live events out to browsers and services over WebSocket or GraphQL subscriptions.
- [Connectors](https://ventstream.dev/docs/connectors/overview.md): The sources VentStream reads from and the sinks it writes to — and what's supported today.
- [Postgres source](https://ventstream.dev/docs/connectors/sources/postgres.md): Stream a Postgres table and its related rows into your target.
- [Neo4j source](https://ventstream.dev/docs/connectors/sources/neo4j.md): Stream a Neo4j graph into denormalized documents with multi-hop fan-out.
- [MongoDB source](https://ventstream.dev/docs/connectors/sources/mongodb.md): Stream a MongoDB replica set or sharded cluster into the sink via change streams.
- [MySQL / MariaDB source](https://ventstream.dev/docs/connectors/sources/mysql.md): Stream a MySQL or MariaDB database into the sink by tailing the row-based binary log.
- [Kafka / Redpanda source](https://ventstream.dev/docs/connectors/sources/kafka.md): Consume Debezium change topics (or raw JSON topics) and stream them into the sink.
- [OpenSearch / Elasticsearch sink](https://ventstream.dev/docs/connectors/sinks/opensearch.md): Write denormalized documents to OpenSearch or Elasticsearch with idempotent bulk upserts.
- [Meilisearch sink](https://ventstream.dev/docs/connectors/sinks/meilisearch.md): Keep Meilisearch indexes continuously in sync with your database — inserts, updates, and deletes, no polling, no re-indexing.
- [Redis sink](https://ventstream.dev/docs/connectors/sinks/redis.md): Maintain deterministic Redis keys from CDC output as retained views or expiring cache entries.
- [MCP server](https://ventstream.dev/docs/guides/mcp-server.md): Give AI agents read-only access to your sink data with ventstream mcp
- [Database TLS and trust](https://ventstream.dev/docs/guides/database-tls.md): Choose system trust, an automatic provider bundle, or a custom CA without weakening server verification.
- [Real-time demo (GraphiQL)](https://ventstream.dev/docs/guides/realtime-demo.md): Stream typed GraphQL subscriptions over NATS in a browser.
- [Reliable Apollo subscriptions](https://ventstream.dev/docs/guides/reliable-apollo-subscriptions.md): Checkpoint, multiplex, reconnect, and replay VentStream GraphQL subscriptions without silently skipping events.
- [Authoring projection specs](https://ventstream.dev/docs/guides/authoring-specs.md): Design a projection that captures what you need without over-fanning-out.
- [Testing a pipeline](https://ventstream.dev/docs/guides/testing.md): Verify create / update / delete propagation and source↔index consistency.
- [One deleted node, 59,498 rebuilds: taming hot nodes in graph CDC](https://ventstream.dev/docs/engineering/neo4j-hot-nodes.md): Why the Neo4j source exists, how graph fan-out inverts under denormalization, and the per-relationship-type hot-endpoint filter that made recompose cascades O(1).
- [VentStream Cloud](https://ventstream.dev/docs/fleet/overview.md): Operate managed VentStream pipelines without putting the control plane in the data path.
- [Fleet resource model](https://ventstream.dev/docs/fleet/resource-model.md): How organizations, environments, pipelines, deployments, and instances relate.
- [Authentication](https://ventstream.dev/docs/fleet/authentication.md): Authenticate ventstreamctl with VentStream Cloud and select the managed organization and environment you want to administer.
- [CLI administration](https://ventstream.dev/docs/fleet/cli.md): Install ventstreamctl and administer VentStream Cloud pipelines, agents, configuration, and operations.
- [Agent enrollment](https://ventstream.dev/docs/fleet/enrollment.md): Bootstrap a managed engine with a one-time grant, then use renewable mTLS workload identity.
- [Managed configuration](https://ventstream.dev/docs/fleet/configuration.md): Create, validate, activate, and roll back immutable VentStream engine configuration revisions.
- [Cloud security model](https://ventstream.dev/docs/fleet/security.md): Identity, tenant isolation, certificate, and operational controls for VentStream Cloud.
- [Install the engine binary](https://ventstream.dev/docs/deploy/native-binary.md): Install and run the standalone VentStream engine on Linux or macOS without Docker or Fleet.
- [Run locally](https://ventstream.dev/docs/deploy/local.md): Build the engine and run it natively on macOS (no Docker) — Postgres CDC to OpenSearch, or the real-time WebSocket/GraphQL gateways.
- [Kubernetes deployment](https://ventstream.dev/docs/deploy/kubernetes.md): Choose standalone engine workloads or Fleet-managed engines, then follow the matching Kubernetes runbook.
- [Standalone engine on Kubernetes](https://ventstream.dev/docs/deploy/kubernetes-standalone.md): Run the open-source engine without VentStream Cloud using canonical configuration, Kubernetes Secrets, and persistent state.
- [Managed agent on Kubernetes](https://ventstream.dev/docs/deploy/kubernetes-managed-engine.md): Deploy a VentStream Cloud-managed CDC or realtime agent into your Kubernetes cluster.
- [Engine environment variables](https://ventstream.dev/docs/reference/engine-env.md): Operator-facing environment variables for standalone and managed VentStream engine workloads.
- [VentStream Cloud API](https://ventstream.dev/docs/reference/control-plane-api.md): Versioned API conventions for managed VentStream resources and operations.
- [Troubleshooting](https://ventstream.dev/docs/reference/troubleshooting.md): Diagnose engine, VentStream Cloud, authentication, enrollment, and local development failures.