Event-Driven Architecture: an editable mindmap

Event-Driven Architecture: an editable mindmap

The interactive MindMap canvas for this explanation — every lane, row and arrow above is a real QueryChart diagram you can open and edit.

How to read this mindmap

• Begin at “Event-Driven Architecture” in the centre, then explore any branch that answers your question. The branch colors keep each group of ideas together.
• Curved lines show relationships; arrowheads appear only where one idea leads to another. Select any idea in the editor to change its text, position, or connections.

Producers

This branch brings together “An event records something that HAPPENED — “order placed”, “user updated” — not an instruction to anyone in particular. Producers don't know who is listening.”.

Event bus

This branch brings together “Events are published to the bus”, “The bus decouples producers from consumers: a producer keeps publishing whether or not any consumer is ready, and consumers subscribe to the events they care about.”.

Consumers

This branch brings together “Consumers process events asynchronously”, “The test of the architecture: add a service that reacts to existing events, and not one producer changes. This is the flexibility the pattern buys.”.

Event history

This branch brings together “The event log is the system of record: every state change, in order, forever. Current state is a projection that can be rebuilt from it.”, “Events can be replayed for audit or recovery”.

Connections across the map

An event records what happened; it is not a command to anyone in particular.

The bus decouples producers from consumers: neither knows the other's identity or schedule.

The event store makes the history a system of record that can be replayed.

Consumers are asynchronous: a slow consumer never blocks a producer.

New consumers join by subscribing: the architecture's whole flexibility claim rests on that.

Key relationships and takeaways

• An event records what happened; it is not a command to anyone in particular.
• The bus decouples producers from consumers: neither knows the other's identity or schedule.
• The event store makes the history a system of record that can be replayed.
• Consumers are asynchronous: a slow consumer never blocks a producer.
• New consumers join by subscribing: the architecture's whole flexibility claim rests on that.

When to use this visual

• Teaching the producer-bus-consumer split to a team moving from request/response to events.
• Designing a new integration: the event store answers whether the history needs to be kept or consumed-and-forgotten.
• Auditing an existing event-driven system for the classic failure: a consumer that is really a synchronous dependency.

How it works

1. Start at the central topic

   Rename “Event-Driven Architecture” if you want to adapt this map to a specific project or lesson.

2. Develop the branches

   Edit the supporting ideas, then add examples and notes where a branch needs more detail.

3. Connect related ideas

   Draw curved connections across branches; use an arrow only when the relationship has a direction.

Frequently asked questions

What is event-driven architecture?

It is an architectural style in which components communicate by publishing and subscribing to events rather than calling each other directly. A service that creates or changes something publishes an event describing what happened; the bus routes it to every subscriber that cares; and an event store keeps the history. Because producers never name their consumers, the system can grow without touching what already exists.

What is the difference between a command and an event?

A command is an instruction aimed at a specific recipient ("process this order") and it expects an outcome. An event is a record that something has already happened ("order placed") and it names no recipient. The distinction matters because commands couple the sender to the receiver, while events leave the receiver free to change. The visual's producers only ever emit events, which is what keeps the bus loose.

What is the event store for?

The event store is the system's retained history: every event, in order, permanently. It serves three purposes: audit (what happened and when), recovery (rebuild a service's state by replaying its events), and extensibility (a new consumer can catch up by reading the past). The visual draws it as the bottom branch because it is a separate use of the same events that consumers process in real time.

What are the failure modes of event-driven architecture?

The classic ones are: events delivered more than once (so consumers must be idempotent), events processed out of order (so consumers must handle ordering), and the dead letter queue (events that fail repeatedly). The visual's asynchronous processing is what makes these manageable (a consumer can retry without blocking the producer) which is why the failure branches in the how-to steps are the practical half of the design.

Edit this mindmap in QueryChart

Open this mindmap as your own editable free canvas. Move ideas, add branches, and draw new connections.

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