--- title: Idempotent Background Workers for LLM Calls in Rails —... description: When an LLM call runs inside a Sidekiq background job, at-least-once delivery semantics can cause double-billing and inconsistent classifications on retry. The... canonical: https://daily.dev/posts/idempotent-background-workers-for-llm-calls-in-rails-danial-asghar-ic5brx4vx twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Idempotent Background Workers for LLM Calls in Rails — Danial Asghar | daily.dev og:description: When an LLM call runs inside a Sidekiq background job, at-least-once delivery semantics can cause double-billing and inconsistent classifications on retry. The... og:url: https://daily.dev/posts/idempotent-background-workers-for-llm-calls-in-rails-danial-asghar-ic5brx4vx og:image: https://api.daily.dev/og/posts/IC5brx4Vx.png og:image:alt: Idempotent Background Workers for LLM Calls in Rails — Danial Asghar 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. # Idempotent Background Workers for LLM Calls in Rails — Danial Asghar **[Ruby Flow](https://daily.dev/sources/rubyflow)** · 14 min read · 0 upvotes · 0 comments ## Summary When an LLM call runs inside a Sidekiq background job, at-least-once delivery semantics can cause double-billing and inconsistent classifications on retry. The post walks through building idempotent Rails workers: starting with a status-based completion gate keyed on the ticket UUID, then explaining its limitation under concurrent duplicate enqueues, and presenting an atomic database-level claim (UPDATE WHERE status IN pending/failed) as the correct fix. Additional failure modes are covered — crash after model call but before write, stuck processing rows needing a reaper, and the transactional outbox pattern for exactly-once enqueue. Common mistakes (per-attempt keys, find_or_create_by without a unique index, swallowing errors) and tradeoffs (eventual consistency, extra state, response caching cost) are also addressed. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [From Delayed Job to Solid Queue: How a 10-Year Rails App Finally Achieved Linear Scaling](https://daily.dev/posts/from-delayed-job-to-solid-queue-how-a-10-year-rails-app-finally-achieved-linear-scaling-f4yyqwfox) · RUBYLAND · 0 upvotes · 0 comments - [Everything you should know about Background Jobs with ActiveJob](https://daily.dev/posts/everything-you-should-know-about-background-jobs-with-activejob-uxyudjznl) · The Miners · 0 upvotes · 0 comments - [Fair by design: orchestrating background jobs in Ruby—Martian Chronicles, Evil Martians’ team blog](https://daily.dev/posts/fair-by-design-orchestrating-background-jobs-in-ruby-martian-chronicles-evil-martians-team-blog-piyszlqky) · Martian Chronicles · 0 upvotes · 0 comments - [The Execution Boundary in Rails](https://daily.dev/posts/the-execution-boundary-in-rails-vyn9zhtyw) · RUBYLAND · 0 upvotes · 0 comments --- Tags: [#rails](https://daily.dev/tags/rails) [View this post on daily.dev](https://daily.dev/posts/idempotent-background-workers-for-llm-calls-in-rails-danial-asghar-ic5brx4vx) ```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":"TechArticle","headline":"Idempotent Background Workers for LLM Calls in Rails — Danial Asghar","url":"https://daily.dev/posts/idempotent-background-workers-for-llm-calls-in-rails-danial-asghar-ic5brx4vx","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/idempotent-background-workers-for-llm-calls-in-rails-danial-asghar-ic5brx4vx"},"datePublished":"2026-07-08T20:20:55.626Z","dateModified":"2026-07-08T20:21:20.534Z","description":"When an LLM call runs inside a Sidekiq background job, at-least-once delivery semantics can cause double-billing and inconsistent classifications on retry. 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