Don MacKinnon: Why Simplicity Beats Cleverness in Software Design

Episode Highlights[00:00:48] What Makes Software MaintainableDon explains why unnecessary complexity is the biggest barrier to maintainability, drawing on themes from A Philosophy of Software Design.[00:03:14] The Cost of Clever AbstractionsA real story from a Node.js API shows how an unused abstraction layer around MongoDB made everything harder without delivering value.[00:04:00] Shaping Teams and Developer ToolsDon describes the structure of the Search Craft engineering team and how the product grew out of recurring pain points in client projects.[00:06:36] Reducing Complexity Through SDK and Infra DesignWhy Search Craft intentionally limits configuration to keep setup fast and predictable.[00:08:33] Lessons From ConsultingRobby and Don compare consulting and product work, including how each environment shapes developers differently.[00:15:34] Inherited Software and Abandoned DependenciesDon shares the problems that crop up when community packages fall behind—especially in ecosystems like React Native.[00:18:00] Evaluating Third-Party LibrariesSignals Don looks for before adopting a dependency: adoption, update cadence, issue activity, and whether the library is “done.”[00:19:40] Designing Code That Remains UnderstandableWhy clear project structure and idiomatic naming matter more than cleverness.[00:20:29] RFCs as a Cultural AnchorHow Don’s team uses RFCs to align on significant changes and avoid decision churn.[00:23:00] Documentation That Adds ContextDocumentation should explain why, not echo code. Don walks through how his team approaches this.[00:24:11] Type Systems and MaintainabilityHow Don’s journey from PHP and JavaScript to TypeScript and Rust changed his approach to structure and communication.[00:27:05] Testing With TypesStable type contracts make tests cleaner and less ambiguous.[00:27:45] Building Trust in AI SystemsDon discusses repeatability, hallucinations, and why tools like MCP matter for grounding LLM behavior.[00:29:28] AI in Developer ToolsSearch Craft’s MCP server lets developers talk to the platform conversationally instead of hunting through docs.[00:33:21] Improving Legacy Systems SlowlyThe Strangler pattern as a practical way to replace old systems one endpoint at a time.[00:34:11] Deep Work and Reducing Reactive NoiseDon encourages developers to carve out time for uninterrupted thinking rather than bouncing between notifications.[00:36:09] Measuring ProgressBuild times, test speeds, and coverage provide signals teams can use to track actual improvement.[00:38:24] Changing Opinions Over a CareerWhy Don eventually embraced TypeScript after originally writing it off.[00:39:15] Industry Trends and Repeating CyclesSPAs, server rendering, and the familiar pendulum swing in web architecture.[00:41:26] Experimentation and Team AutonomyHow POCs and side projects surface organically within Don’s team.[00:44:42] Growing Skills Through Intentional GoalsSetting learning targets in 1:1s to support long-term developer growth.[00:47:19] Where to Find DonLinkedIn, Blue Sky, and his site: donmckinnon.dev.Resources MentionedA Philosophy of Software Design by John OusterhoutJohn Ousterhout’s Maintainable.fm Interview (Episode 131)Search CraftElasticAlgoliaWordPress Plugin DirectoryRequest for Comments (RFC)Strangler Fig PatternC2 WikiModel Context Protocol (MCP)Glam AIAubrey/Maturin Series by Patrick O’BrianMaster and Commanderdonmckinnon.devThanks to Our Sponsor!Turn hours of debugging into just minutes! AppSignal is a performance monitoring and error-tracking tool designed for Ruby, Elixir, Python, Node.js, Javascript, and other frameworks.It offers six powerful features with one simple interface, providing developers with real-time insights into the performance and health of web applications.Keep your coding cool and error-free, one line at a time! Use the code maintainable to get a 10% discount for your first year. Check them out! Subscribe to Maintainable on:Apple PodcastsSpotifyOr search "Maintainable" wherever you stream your podcasts.Keep up to date with the Maintainable Podcast by joining the newsletter.