--- title: Why Retries Break Your Java APIs (And How Idempotency... description: Retries in distributed systems can silently corrupt data without idempotency. This guide explains how to implement idempotency keys based on IETF standards... canonical: https://daily.dev/posts/xozpre2am twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Why Retries Break Your Java APIs (And How Idempotency Fixes It) | daily.dev og:description: Retries in distributed systems can silently corrupt data without idempotency. This guide explains how to implement idempotency keys based on IETF standards... og:url: https://daily.dev/posts/xozpre2am og:image: https://api.daily.dev/og/posts/xoZpre2aM.png og:image:alt: Post cover image og:image:width: 1200 og:image:height: 630 og:locale: 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. # Why Retries Break Your Java APIs (And How Idempotency Fixes It) **[Özkan Pakdil](https://daily.dev/sources/yhtxohtmgtdk1f5lkdkse)** · [@ozkanpakdil](https://daily.dev/ozkanpakdil) · 1 upvotes · 0 comments ## Summary Retries in distributed systems can silently corrupt data without idempotency. This guide explains how to implement idempotency keys based on IETF standards using Java 21 and Quarkus. It covers the data model, service layer with proper concurrency handling, REST endpoint implementation with fingerprint validation, manual testing with curl, and production considerations like TTL cleanup. The pattern prevents duplicate side effects by storing request fingerprints and replaying cached responses for identical retry attempts, working for both REST APIs and message-driven workflows. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Idempotency Is Easy Until the Second Request Is Different](https://daily.dev/posts/idempotency-is-easy-until-the-second-request-is-different-skbwedvu3) · Hacker News · 0 upvotes · 0 comments - [How to Stop Charging Customers Twice: A Practical Idempotency Guide](https://daily.dev/posts/how-to-stop-charging-customers-twice-a-practical-idempotency-guide-m6qetcboi) · The T-Shaped Dev · 0 upvotes · 1 comments - [Idempotent Spring Boot: Safe REST with One Annotation](https://daily.dev/posts/idempotent-spring-boot-safe-rest-with-one-annotation-ubrhbkqcl) · Foojay.io · 12 upvotes · 0 comments - [From HTTP Retries to Kafka Redelivery: Building End-to-End Idempotency with FastAPI](https://daily.dev/posts/from-http-retries-to-kafka-redelivery-building-end-to-end-idempotency-with-fastapi-m2qkobimp) · Medium · 0 upvotes · 0 comments - [Idempotency: What, Why and How](https://daily.dev/posts/idempotency-what-why-and-how-qrypjmflf) · W endell Adriel · 54 upvotes · 3 comments --- Tags: [#java](https://daily.dev/tags/java), [#architecture](https://daily.dev/tags/architecture), [#postgresql](https://daily.dev/tags/postgresql), [#distributed-systems](https://daily.dev/tags/distributed-systems), [#quarkus](https://daily.dev/tags/quarkus) [View this post on daily.dev](https://daily.dev/posts/xozpre2am) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"DiscussionForumPosting","mainEntityOfPage":"https://daily.dev/posts/xozpre2am","headline":"Why Retries Break Your Java APIs (And How Idempotency Fixes It)","text":"Shared: Why Retries Break Your Java APIs (And How Idempotency Fixes It)","url":"https://daily.dev/posts/xozpre2am","datePublished":"2026-01-12T07:52:26.545Z","dateModified":"2026-01-12T07:53:06.882Z","author":{"@type":"Person","name":"Özkan Pakdil","url":"https://daily.dev/ozkanpakdil","image":"https://media.daily.dev/image/upload/s--ihPlqRre--/f_auto/v1758259464/avatars/avatar_yHtxohtmgtdK1F5lKdKSe?_a=BAMAK+ZW0","description":"Coding since Commodore 64(1993), works with Linux/cloud/Java/spring boot/hibernate/C#/PostgreSQL","interactionStatistic":{"@type":"InteractionCounter","interactionType":{"@type":"EndorseAction"},"userInteractionCount":6890}},"image":"https://media.daily.dev/image/upload/s--HRgLpUt6--/f_auto/v1722860399/public/Placeholder%2003","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":1},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"sharedContent":{"@type":"WebPage","url":"https://api.daily.dev/r/1nZuKauWH"},"isPartOf":{"@type":"WebPage","url":"https://daily.dev/sources/yhtxohtmgtdk1f5lkdkse","name":"Özkan Pakdil"}} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Özkan Pakdil","item":"https://daily.dev/sources/yhtxohtmgtdk1f5lkdkse"},{"@type":"ListItem","position":3,"name":"Why Retries Break Your Java APIs (And How Idempotency Fixes It)"}]} ```