AWS EventBridge Cheat Sheet

Event bus rules, patterns, schedules, and SDK snippets for routing events between AWS services and SaaS apps.

2 PagesIntermediateFeb 10, 2026

Create a Rule with an Event Pattern

Route events matching a pattern to a target using the AWS CLI.

bash

# Create a rule that matches EC2 instance state changesaws events put-rule \  --name "ec2-state-change" \  --event-pattern '{    "source": ["aws.ec2"],    "detail-type": ["EC2 Instance State-change Notification"],    "detail": { "state": ["running", "stopped"] }  }'# Attach a Lambda function as the targetaws events put-targets \  --rule "ec2-state-change" \  --targets '[{"Id": "1", "Arn": "arn:aws:lambda:us-east-1:123456789012:function:notify"}]'# Grant EventBridge permission to invoke the Lambdaaws lambda add-permission \  --function-name notify \  --statement-id eventbridge-invoke \  --action lambda:InvokeFunction \  --principal events.amazonaws.com \  --source-arn arn:aws:events:us-east-1:123456789012:rule/ec2-state-change

Custom Event Bus & PutEvents (SDK)

Publish a custom application event to a dedicated event bus using boto3.

python

import boto3, jsonclient = boto3.client("events")response = client.put_events(    Entries=[        {            "Source": "myapp.orders",            "DetailType": "OrderPlaced",            "Detail": json.dumps({"orderId": "o-123", "total": 49.99}),            "EventBusName": "orders-bus",        }    ])print(response["Entries"])  # check for EventId / ErrorCode per entry

Scheduled Rule (cron / rate)

Trigger a target on a fixed schedule instead of an event pattern.

bash

# Every 15 minutesaws events put-rule \  --name "poll-every-15-min" \  --schedule-expression "rate(15 minutes)"# Cron: 8am UTC every weekdayaws events put-rule \  --name "weekday-morning-report" \  --schedule-expression "cron(0 8 ? * MON-FRI *)"

Core Concepts

The building blocks of EventBridge you'll reference constantly.

Event bus- a router that receives events; default, custom, or partner (SaaS) buses
Rule- matches events via an event pattern or a schedule expression
Target- up to 5 destinations per rule (Lambda, SQS, SNS, Step Functions, etc.)
Event pattern- JSON filter matched against source, detail-type, and detail fields
Archive & Replay- store matched/unmatched events and replay them into a bus later
Schema registry- infers and stores JSON schemas for events flowing through a bus
Input transformer- reshapes the event JSON before it reaches the target

Pro Tip

Use content filtering operators like `anything-but`, `prefix`, and `numeric` ranges in event patterns instead of chaining multiple rules — it cuts costs and keeps routing logic in one place.

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