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

# FlowWarden Stream

> Declarative MongoDB Change Streams for Spring Boot

## What is FlowWarden?

FlowWarden Stream Core is an annotation-driven library that brings **declarative MongoDB Change Streams** to Spring Boot. Zero additional dependencies — just Spring Data MongoDB.

<CardGroup cols={2}>
  <Card title="Quickstart" icon="rocket" href="/quickstart">
    Add the dependency and create your first handler in minutes.
  </Card>

  <Card title="How it Works" icon="gears" href="/concepts/how-it-works">
    Understand Change Streams, resume tokens, and the FlowWarden lifecycle.
  </Card>

  <Card title="Annotations Reference" icon="tags" href="/reference/change-stream">
    Full reference for all FlowWarden annotations.
  </Card>

  <Card title="Guides" icon="book" href="/guides/imperative-vs-reactive">
    Step-by-step guides for filtering, retry, deployment modes, and more.
  </Card>

  <Card title="Source on GitHub" icon="github" href="https://github.com/flowwarden-io/flowwarden-stream-core">
    Browse the `flowwarden-stream-core` source, issues, and releases.
  </Card>
</CardGroup>

## Key Features

* **`@ChangeStream` declarative handlers** with typed event callbacks
* **Automatic checkpoint & resume** using MongoDB-backed resume tokens
* **Dead Letter Queue** for failed events with retention policies
* **Exponential backoff retry** via `@RetryPolicy`
* **Server-side filtering** with `@Pipeline` (MongoDB aggregation pushed down to the oplog)
* **Application-side filtering** with `@Filter` (Java predicates with Spring bean access)
* **Dual execution modes** — Imperative (Spring MVC) or Reactive (WebFlux)
* **Zero additional dependencies** — only requires Spring Data MongoDB

## Compatibility

| Requirement         | Version             |
| ------------------- | ------------------- |
| Java                | 17+ (recommend 21+) |
| Spring Boot         | 3.2.x+              |
| Spring Data MongoDB | 4.2.x+              |
| MongoDB             | 6.0+ (Replica Set)  |