# 10 Common Mistakes When Building a Component Library > The most common component library mistakes engineering teams make — from over-engineering APIs to skipping accessibility — and how to avoid them before they compound. - **Published:** 2025-04-12 - **Author:** Clixo - **Reading time:** 5 min read - **Tags:** component library, design systems, engineering, best practices - **Canonical URL:** https://clixo.sh/blog/common-mistakes-building-a-component-library Most component libraries fail not because the engineering was poor but because of decisions made in the first few weeks that look fine until the library is in production across multiple teams. By then, the cost of fixing them is high enough that teams route around the library instead. These are the mistakes that cause that outcome. ```mermaid flowchart TD TOK["Design tokens"] --> PRIM["Primitive components"] PRIM --> COMP["Composite components"] COMP --> PAT["Page patterns"] TOK --> DOC["Documentation and Storybook"] PRIM --> DOC COMP --> DOC DOC --> CONS["Consuming teams"] PAT --> CONS ``` ## Mistake 1: Starting with Components Instead of Tokens Building buttons before establishing a color palette and spacing scale means every component will hardcode values that should be variables. When the first rebrand arrives — or the first dark mode request — you are editing dozens of components instead of updating one token file. Start with decisions. Components come after. ## Mistake 2: Naming Components Cleverly Instead of Clearly "CtaBlock," "HeroUnit," "ActionStrip." These names make sense to the person who invented them and to nobody else three months later. Component names should be boring on purpose. `Button`, `FormField`, `Modal`, `DataTable`, `EmptyState`. Predictability in naming reduces the cognitive load for every engineer who uses the library for the first time. ## Mistake 3: Building for the Average Case and Ignoring Edge Cases A button that works when the label is five characters fails when the label wraps to two lines. A card that looks correct with one line of text breaks with a long product description. A table that renders well with ten rows struggles with three hundred. Document and test edge cases at build time, not when a consuming team reports a production bug. The edge case behavior is part of the component's contract. ## Mistake 4: Designing Components in Isolation Components that were designed without considering how they nest and compose produce awkward gaps, unexpected overflow, and spacing conflicts when combined. Before a component reaches stable, test it in the layouts and compositions where it will actually be used. Composition testing is not optional. ## Mistake 5: Skipping Keyboard and Screen Reader Behavior Accessibility is not a layer you add after a component works visually. A modal without focus trapping, a dropdown without arrow-key navigation, an icon button without an accessible name — these are broken components, not incomplete ones. Build the keyboard model and ARIA attributes in the first pass. Retrofitting them after adoption is expensive and often incomplete. ## Mistake 6: Shipping Without Documentation A component that exists in the library but has no documentation about its props, its states, its keyboard behavior, or when to use it will either be ignored or misused. Documentation is not a nice-to-have — it is what makes the component usable without asking the person who built it. Use Storybook's autodocs, write usage guidelines, and document edge cases and known limitations alongside the component. ## Mistake 7: Designing APIs That Are Too Opinionated A `Button` component that has exactly one visual variant, one size, and no composition options will be forked the first time a team needs something slightly different. APIs should be flexible enough to cover the real range of use cases without requiring escape hatches. Expose `className` and `style` overrides. Use render props or slots for complex customization. The goal is to make the library the path of least resistance, not a constraint. ## Mistake 8: Designing APIs That Are Too Permissive The opposite failure is equally common. A component with 40 props, all optional, with undocumented interactions between them is not flexible — it is unpredictable. Permissive APIs produce inconsistency because different engineers make different choices from the same option set. A well-designed API guides engineers toward the correct implementation by making the right thing easy and the wrong thing hard. ## Mistake 9: No Versioning Strategy Shipping a component library with no versioning strategy means every breaking change lands in consuming teams without warning. Every consuming team pins to a version that works and stops upgrading. The library forks into as many versions as there are teams. Adopt semantic versioning from the first release. Write a changelog for every version. Provide migration guides for breaking changes. Treat upgrading as something that should be safe and predictable. ## Mistake 10: Treating the Library as a Finished Product A component library is not finished when it ships. New requirements arrive. Edge cases surface in production. Accessibility audits find gaps. Consuming teams have legitimate feature requests. Without a process for accepting contributions, prioritizing improvements, and releasing updates, the library stops evolving. Teams that need things the library does not offer build locally — and the library becomes less relevant over time. Governance is what keeps the library alive. ## The Cost of Getting These Wrong Each of these mistakes individually is recoverable. Combined, they produce a library that teams do not trust, do not upgrade, and quietly fork. The fix is almost never rebuilding from scratch — it is a migration project that consumes more engineering time than the original build. The stakes are highest in the first three months, when patterns get established and adoption habits form. Get the token foundation right, design APIs for the real range of cases, document alongside the build, and establish a versioning and contribution model before you need one. Those four investments prevent most of the failure modes on this list. 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