Namastack Outbox is an open-source transactional outbox implementation for Spring Boot, built for reliable
event-driven applications with Java and Kotlin.
It persists events atomically with your business data and processes them asynchronously with built-in support for
retries, ordering, horizontal scaling and observability — without requiring additional infrastructure.
Explore the documentation →
Why Namastack Outbox?
Reliable event publishing becomes surprisingly difficult once failures, retries, concurrency and multiple application
instances enter the picture.
Namastack Outbox handles these concerns as part of your Spring Boot application.
- Transactional guarantees — persist events atomically with your business data
- At-least-once delivery — configurable retry and failure handling
- Strict ordering — preserve processing order for events sharing the same key
- Horizontal scaling — automatic partitioning and rebalancing across application instances
- Observability — metrics, Actuator integration and distributed tracing
- Context propagation — preserve tracing, tenant and correlation information
- Flexible persistence — JDBC for relational databases and MongoDB
- Messaging integrations — Kafka, RabbitMQ and AWS SNS
- Spring Modulith integration — production-grade event externalization using the transactional outbox pattern
How It Works
Business data and its outbox record commit together. Namastack delivers the record asynchronously with ordering and
retries.
Documentation
Everything you need to get started, configure and operate Namastack Outbox is available in the documentation.
Releases and Compatibility
We make every effort to preserve backward compatibility and keep upgrades straightforward. While we cannot
guarantee strict Semantic Versioning for every change, we aim to keep necessary adjustments small and explain them clearly.
Read the Support and Update Policy for compatibility
expectations, maintenance support and upgrade guidance.
Community
Namastack Outbox is open source and contributions of all sizes are welcome.
Contributors
Thanks to everyone who has contributed to Namastack Outbox.
Support the Project
Namastack Outbox is independently developed and maintained as open-source software.
If Namastack Outbox helps you or your team, sponsoring the project helps support its continued development, maintenance
and documentation.
License
Namastack Outbox is licensed under the Apache License 2.0.
Applications using Spring Data JPA use the JDBC outbox starter with their existing JPA transaction
manager and DataSource.
