--- title: How Dependency Injection Works in NestJS | daily.dev description: A brief explainer on how dependency injection works in NestJS, using a pizza chef analogy to illustrate tight coupling vs. injected dependencies. Shows why... canonical: https://daily.dev/posts/how-dependency-injection-works-in-nestjs-htekyk7qh twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: How Dependency Injection Works in NestJS | daily.dev og:description: A brief explainer on how dependency injection works in NestJS, using a pizza chef analogy to illustrate tight coupling vs. injected dependencies. Shows why... og:url: https://daily.dev/posts/how-dependency-injection-works-in-nestjs-htekyk7qh og:image: https://api.daily.dev/og/posts/hTEKYK7Qh.png og:image:alt: How Dependency Injection Works in NestJS 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. # How Dependency Injection Works in NestJS **[JavaScript Mastery](https://daily.dev/sources/javascriptmastery)** 路 1 min read 路 16 upvotes 路 4 comments ## Summary A brief explainer on how dependency injection works in NestJS, using a pizza chef analogy to illustrate tight coupling vs. injected dependencies. Shows why manually instantiating services inside methods is problematic and how NestJS modules handle service registration and injection correctly. ## 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. **@projekcomm** 路 2 upvotes > LOL! The thumbnail 馃槀馃槀馃槀 **@alwaisy** 路 0 upvotes > does it matter. i know it or don't know it. at least my coding agent does not care. in 2021. i did care so much what the fuck closures vs hoisting are. who cares now. **@jobayerhossen** 路 0 upvotes > good ## Similar posts on daily.dev - [NestJS Dependency Injection: Source Code, Type Erasure Hacks, and Building Your Own IoC Container from Scratch](https://daily.dev/posts/nestjs-dependency-injection-source-code-type-erasure-hacks-and-building-your-own-ioc-container-fr-74fnlhzd6) 路 Medium 路 0 upvotes 路 0 comments --- Tags: [#typescript](https://daily.dev/tags/typescript), [#dependency-injection](https://daily.dev/tags/dependency-injection), [#nestjs](https://daily.dev/tags/nestjs) [View this post on daily.dev](https://daily.dev/posts/how-dependency-injection-works-in-nestjs-htekyk7qh) ```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":"How Dependency Injection Works in NestJS","url":"https://daily.dev/posts/how-dependency-injection-works-in-nestjs-htekyk7qh","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/how-dependency-injection-works-in-nestjs-htekyk7qh"},"datePublished":"2026-07-10T08:36:47.675Z","dateModified":"2026-09-13T18:26:02.196Z","description":"A brief explainer on how dependency injection works in NestJS, using a pizza chef analogy to illustrate tight coupling vs. injected dependencies. 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The thumbnail 馃槀馃槀馃槀","datePublished":"2026-07-11T04:49:01.748Z","url":"https://daily.dev/posts/hTEKYK7Qh#c-UChI3wVQA","author":{"@type":"Person","name":"Projekcomm","url":"https://daily.dev/projekcomm","image":"https://lh3.googleusercontent.com/a/ACg8ocLMal8dqtQpCaFKR_2Qj0-5jQ7_YZNHGq5ZMFQHZI4f0VWGwg7O=s96-c"},"interactionStatistic":{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":2}},{"@type":"Comment","text":"does it matter. i know it or don鈥檛 know it. at least my coding agent does not care. in 2021. i did care so much what the fuck closures vs hoisting are. who cares now.","datePublished":"2026-07-12T08:35:29.960Z","url":"https://daily.dev/posts/hTEKYK7Qh#c-sDTctkViB","author":{"@type":"Person","name":"Awais Alwaisy","url":"https://daily.dev/alwaisy","image":"https://avatars.githubusercontent.com/u/102944304?v=4"}},{"@type":"Comment","text":"good","datePublished":"2026-07-11T12:38:54.050Z","url":"https://daily.dev/posts/hTEKYK7Qh#c-IHmYsTDg1","author":{"@type":"Person","name":"Jobayer Hossen","url":"https://daily.dev/jobayerhossen","image":"https://lh3.googleusercontent.com/a/ACg8ocKPWsJsesL2GMS7y3dBEvZRr7NoVelPXt3Q6EGSbMyYadlvC_s=s96-c"}}]} ```