# Amazon EventBridge

> A switchboard that routes "something happened" messages to whoever cares.

- Level: Intermediate
- Topics: AWS
- URL: https://tidbit.legios.com.ar/amazon-eventbridge/
- In Spanish: [Amazon EventBridge](https://tidbit.legios.com.ar/es/amazon-eventbridge/)

Many systems are easier to build if parts announce what happened instead of calling each other directly. An order was placed, a file was uploaded, a server stopped. **EventBridge** is the AWS service that carries those announcements, called **events**: small JSON messages that go into an **event bus**.

On the bus you set **rules**. Each rule describes a pattern, like "events from the orders app where the total is above 1000", and one or more targets to send matching events to: an AWS Lambda function, an Amazon SQS queue, an AWS Step Functions workflow, another account. The app that emits the event does not know or care who is listening. Adding a new reaction, say a fraud check, means adding a rule, not changing the orders app.

AWS services already publish their own events to a default bus (an EC2 machine changed state, a backup finished), and many SaaS tools can send theirs too. EventBridge also includes a **scheduler** for running something at a set time or on a repeating schedule, which replaced the old trick of cron jobs on a server. It used to be called CloudWatch Events, and some older documentation still uses that name.

## An analogy

The announcements board of a building. Residents pin notices ("water cut on Tuesday") without knowing who will read them, and each neighbor has asked the concierge to alert them only about the kind of notice they care about.

## Keep in mind

- Events are small JSON messages describing something that happened.
- Rules match events by pattern and route them to targets like Lambda or SQS.
- Senders and receivers stay decoupled; new listeners need no change to the sender.
- Includes a scheduler for timed and recurring tasks.

## Go deeper

- [What is Amazon EventBridge? (official docs)](https://docs.aws.amazon.com/eventbridge/latest/userguide/eb-what-is.html)
- [Amazon EventBridge](https://aws.amazon.com/eventbridge/)

## Related terms

- [Server](https://tidbit.legios.com.ar/server/): A computer whose job is to answer requests from other computers, all day, every day.
- [JSON](https://tidbit.legios.com.ar/json/): The plain-text format programs use to hand each other structured data.
- [AWS Lambda](https://tidbit.legios.com.ar/aws-lambda/): Run a piece of code only when something happens, with no server to manage.
- [Amazon SQS](https://tidbit.legios.com.ar/amazon-sqs/): A waiting line for messages between programs, so none of them gets lost.
- [AWS Step Functions](https://tidbit.legios.com.ar/aws-step-functions/): A flowchart that runs: it chains steps, retries failures and remembers where it was.
- [Amazon EC2](https://tidbit.legios.com.ar/amazon-ec2/): Virtual computers you rent by the hour, in any size, and switch off when done.
- [Backup](https://tidbit.legios.com.ar/backup/): A separate copy of your data, kept so you can get it back when the original is lost.
- [SaaS, PaaS and IaaS](https://tidbit.legios.com.ar/saas-paas-iaas/): Three ways to rent computing, depending on how much of the work you hand over.