Mock Event Sourcing Payload Generator

How to use

1. 1️⃣
   Choose your options above
2. 2️⃣
   Click Generate
3. 3️⃣
   Copy your result

Detailed instructions

1. Select the domain that matches your system — ecommerce, payments, inventory, user management, or messaging.
2. Set the event count to the batch size you need, such as 6 for a quick test or 20 for a load scenario.
3. Click Generate to produce a list of fully-structured domain event JSON payloads.
4. Copy individual payloads or the full batch and paste into your test fixture, broker producer, or event store client.
5. Adjust the domain or count and regenerate to create varied event sequences for different test scenarios.

Use Cases

• •Seeding a Kafka topic via kafka-console-producer with realistic payments domain events
• •Populating EventStoreDB or Marten with sample aggregate histories for integration tests
• •Feeding a CQRS projection handler in Jest or pytest to verify read-model update logic
• •Demoing a new event consumer microservice to stakeholders without a live write-side pipeline
• •Bootstrapping Cypress or Postman test fixtures for saga and process manager implementations

Tips

• →Generate 10+ events in the payments domain, then group by aggregate ID to simulate realistic multi-step transaction histories.
• →After generating, standardize the aggregate ID across 5–6 events to test projection handlers that rebuild state from a single stream.
• →Use the causation ID field to manually chain events — set one event's causation ID to the previous event's ID to represent a saga step.
• →For Kafka testing, generate events in ecommerce and inventory domains separately to simulate two upstream topics feeding one consumer.
• →Combine outputs from multiple domain selections to test event routers or dispatchers that must handle heterogeneous event types.
• →When teaching CQRS, generate 3 user-management events and walk through rebuilding the read model manually — the realistic field names make the lesson concrete.

FAQ