--- title: Why Testability is Software Rule #1 | daily.dev description: Architecting for testability is framed as a core software design principle, not an afterthought. The key idea is that developers need fast feedback loops at... canonical: https://daily.dev/posts/why-testability-is-software-rule-1-tg8ugp6ld twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Why Testability is Software Rule #1 | daily.dev og:description: Architecting for testability is framed as a core software design principle, not an afterthought. The key idea is that developers need fast feedback loops at... og:url: https://daily.dev/posts/why-testability-is-software-rule-1-tg8ugp6ld og:image: https://api.daily.dev/og/posts/Tg8UgP6Ld.png og:image:alt: Why Testability is Software Rule #1 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 Testability is Software Rule #1 **[Continuous Delivery](https://daily.dev/sources/continuousdelivery)** · 1 min read · 0 upvotes · 0 comments ## Summary Architecting for testability is framed as a core software design principle, not an afterthought. The key idea is that developers need fast feedback loops at multiple scales — unit tests provide speed but aren't sufficient alone. Larger-scale tests must also run quickly enough to be useful during development, which requires deliberate architectural decisions that prioritize how fast and effectively feedback can be obtained. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Testing is software engineering](https://daily.dev/posts/testing-is-software-engineering-9un4ckzn6) · thoughbot · 129 upvotes · 6 comments - [How to be useful as a software architect](https://daily.dev/posts/how-to-be-useful-as-a-software-architect-4fbizapkg) · swizec.com · 1 upvotes · 0 comments --- Tags: [#testing](https://daily.dev/tags/testing), [#architecture](https://daily.dev/tags/architecture), [#tdd](https://daily.dev/tags/tdd) [View this post on daily.dev](https://daily.dev/posts/why-testability-is-software-rule-1-tg8ugp6ld) ```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":"Why Testability is Software Rule #1","url":"https://daily.dev/posts/why-testability-is-software-rule-1-tg8ugp6ld","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/why-testability-is-software-rule-1-tg8ugp6ld"},"datePublished":"2026-07-21T16:41:11.558Z","dateModified":"2026-07-21T16:41:25.346Z","description":"Architecting for testability is framed as a core software design principle, not an afterthought. The key idea is that developers need fast feedback loops at...","image":"https://i.ytimg.com/vi/tzCviBI-n8M/sddefault.jpg","thumbnailUrl":"https://i.ytimg.com/vi/tzCviBI-n8M/sddefault.jpg","isAccessibleForFree":true,"articleSection":"Continuous Delivery","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Continuous Delivery","logo":"https://media.daily.dev/image/upload/s---b6TAqpH--/f_auto/v1730404995/logos/continuousdelivery","url":"https://daily.dev/sources/continuousdelivery"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/why-testability-is-software-rule-1-tg8ugp6ld","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"testing,architecture,tdd","timeRequired":"PT1M","video":{"@type":"VideoObject","name":"Why Testability is Software Rule #1","description":"Architecting for testability is framed as a core software design principle, not an afterthought. The key idea is that developers need fast feedback loops at...","thumbnailUrl":"https://i.ytimg.com/vi/tzCviBI-n8M/sddefault.jpg","uploadDate":"2026-07-21T16:41:11.558Z","duration":"PT1M","url":"https://api.daily.dev/r/Tg8UgP6Ld","embedUrl":"https://www.youtube.com/embed/tzCviBI-n8M"}} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Continuous Delivery","item":"https://daily.dev/sources/continuousdelivery"},{"@type":"ListItem","position":3,"name":"Why Testability is Software Rule #1"}]} ```