Developer library · 36 free recipes

Effects, ready to ship.

Free motion recipes for real websites. Browse practical CSS and JavaScript patterns, copy a focused implementation, or let an LLM fetch the exact effect through the Site Commander API or MCP.

Browse library How to advise an LLM

const effect = "fade-up-reveal";
await ship(effect);

All effects Scroll reveals Micro-interactions Navigation Backgrounds Text motion Components Media & layout Library starters

Featured recipeNavigation

Scroll progress line

A single fixed progress line that gives long-form pages a clear sense of place.

CSSscrolllow overhead

<div data-sc-effect="scroll-progress" aria-hidden="true"></div>

[data-sc-effect="scroll-progress"] {
  position: fixed; inset: 0 auto auto 0; z-index: 10;
  width: 100%; height: 3px; transform: scaleX(0); transform-origin: left;
  background: #5b5ce2; pointer-events: none;
}

const progress = document.querySelector('[data-sc-effect="scroll-progress"]');
let progressTicking = false;
window.addEventListener('scroll', () => {
  if (progressTicking) return;
  progressTicking = true;
  requestAnimationFrame(() => {
    const max = document.documentElement.scrollHeight - window.innerHeight;
    progress.style.transform = `scaleX(${max > 0 ? window.scrollY / max : 0})`;
    progressTicking = false;
  });
}, { passive: true });

The foundation

Native recipes

Small, composable patterns you can paste into a plain HTML site, a CMS, or a generated staging build.

Interactive preview

NavigationCC0-style snippets

Active nav underline

A sliding active indicator that makes the current navigation context obvious.

Small tab bars, section navigation, and product navs.

[data-sc-effect="nav-underline"] { --sc-underline-x: 0%; --sc-underline-width: 0px; position: relative; }
[data-sc-effect="nav-underline"]::after {
  content: ""; position: absolute; left: var(--sc-underline-x); bottom: -5px;
  width: var(--sc-underline-width); height: 2px; background: currentColor;
  transition: left 180ms ease, width 180ms ease;
}
@media (prefers-reduced-motion: reduce) { [data-sc-effect="nav-underline"]::after { transition: none; } }

const nav = document.querySelector('[data-sc-effect="nav-underline"]');
nav.querySelectorAll('a').forEach((link) => {
  link.addEventListener('pointerenter', () => {
    nav.style.setProperty('--sc-underline-x', `${link.offsetLeft}px`);
    nav.style.setProperty('--sc-underline-width', `${link.offsetWidth}px`);
  });
  link.addEventListener('click', (event) => {
    event.preventDefault();
    nav.querySelectorAll('a').forEach((item) => item.removeAttribute('aria-current'));
    link.setAttribute('aria-current', 'page');
  });
});

Bring a library when it earns its weight

Free library starters

Version-pinned starting points for open-source libraries. Review the license and performance tradeoff before adding another dependency.

For GPTs and other agents

Tell the LLM how to use the library.

Give the model a clear selection loop. It should discover, fetch, compose, then explain where it placed the effect instead of inventing a new dependency.

Recommended instruction

Use this in a system or developer prompt when the model can access the REST API or MCP.

When a user asks for website motion or an interaction effect:
1. Search Site Commander’s effects catalog before writing a new animation.
2. Prefer a native recipe when it meets the request; use a free MIT library only when it materially reduces complexity.
3. Fetch the chosen effect by effect_id and inspect its reduced-motion and accessibility notes.
4. Compose the effect for the user’s real selector. Keep the selector scoped and do not rewrite unrelated styles.
5. Return the exact files or insertion points, explain the dependency (if any), and mention keyboard, touch, and prefers-reduced-motion behavior.
6. Never add a library from an untrusted CDN or use a versionless URL when a pinned URL is available.

Use the Site Commander tools `sitecommander_effects_search`, `sitecommander_effects_fetch`, and `sitecommander_effects_compose` for this workflow.

No command center required.The catalog is public and read-only. Use the REST endpoints from any site or connect the bearer-authenticated MCP endpoint to an agent.

GET /api/effects MCP setup