--- title: "Inbox & Outbox patterns for reliable event processing" url: https://daily.dev/posts/inbox-outbox-patterns-for-reliable-event-processing-j8qt0su06 source_url: https://theburningmonk.com/2026/05/inbox-outbox-patterns-for-reliable-event-processing type: article source: "theburningmonk.com" published: 2026-05-05T01:13:37.914Z updated: 2026-05-05T01:14:00.885Z tags: ["architecture", "aws-dynamodb"] reading_time: 7 upvotes: 37 comments: 2 language: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Inbox & Outbox patterns for reliable event processing **[theburningmonk.com](https://daily.dev/sources/theburningmonk)** · 7 min read · 37 upvotes · 2 comments ## Summary Explains the Outbox and Inbox patterns for building reliable event-driven systems. The Outbox pattern solves the problem of database updates succeeding while event publishing fails, by writing both the business record and the outbox item atomically, then publishing asynchronously via DynamoDB Streams and EventBridge Pipes. The Inbox pattern addresses duplicate event delivery by storing processed event IDs as deduplication keys using conditional DynamoDB writes. The post also covers the distinction between inbox-based deduplication and idempotency keys, and discusses safe ordering of inbox writes relative to business logic, including a locking approach for flows with intermediate side effects. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Community discussion Top comments from developers on daily.dev. **@joudawad** · 0 upvotes > Great share! One of the best patterns that ever engineer should know how to use ## Similar posts on daily.dev - [How to Implement the Outbox Pattern in Distributed Systems](https://daily.dev/posts/how-to-implement-the-outbox-pattern-in-distributed-systems-0xhg3kran) · C\# Corner · 4 upvotes · 0 comments --- Tags: [#architecture](https://daily.dev/tags/architecture), [#aws-dynamodb](https://daily.dev/tags/aws-dynamodb) [View this post on daily.dev](https://daily.dev/posts/inbox-outbox-patterns-for-reliable-event-processing-j8qt0su06)