diff --git a/.gitignore b/.gitignore
index bf38bbc4e..2c8e89efc 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,6 +7,8 @@ node_modules
 /index.js
 /internal.*
 /store.js
+/easing.js
+/transition.js
 /scratch/
 /coverage/
 /coverage.lcov/
diff --git a/easing.mjs b/easing.mjs
new file mode 100644
index 000000000..87298b7cf
--- /dev/null
+++ b/easing.mjs
@@ -0,0 +1,173 @@
+/*
+Adapted from https://github.com/mattdesl
+Distributed under MIT License https://github.com/mattdesl/eases/blob/master/LICENSE.md
+*/
+
+export function backInOut(t) {
+	var s = 1.70158 * 1.525;
+	if ((t *= 2) < 1) return 0.5 * (t * t * ((s + 1) * t - s));
+	return 0.5 * ((t -= 2) * t * ((s + 1) * t + s) + 2);
+}
+
+export function backIn(t) {
+	var s = 1.70158;
+	return t * t * ((s + 1) * t - s);
+}
+
+export function backOut(t) {
+	var s = 1.70158;
+	return --t * t * ((s + 1) * t + s) + 1;
+}
+
+export function bounceOut(t) {
+	var a = 4.0 / 11.0;
+	var b = 8.0 / 11.0;
+	var c = 9.0 / 10.0;
+
+	var ca = 4356.0 / 361.0;
+	var cb = 35442.0 / 1805.0;
+	var cc = 16061.0 / 1805.0;
+
+	var t2 = t * t;
+
+	return t < a
+		? 7.5625 * t2
+		: t < b
+		? 9.075 * t2 - 9.9 * t + 3.4
+		: t < c
+		? ca * t2 - cb * t + cc
+		: 10.8 * t * t - 20.52 * t + 10.72;
+}
+
+export function bounceInOut(t) {
+	return t < 0.5
+		? 0.5 * (1.0 - bounceOut(1.0 - t * 2.0))
+		: 0.5 * bounceOut(t * 2.0 - 1.0) + 0.5;
+}
+
+export function bounceIn(t) {
+	return 1.0 - bounceOut(1.0 - t);
+}
+
+export function circInOut(t) {
+	if ((t *= 2) < 1) return -0.5 * (Math.sqrt(1 - t * t) - 1);
+	return 0.5 * (Math.sqrt(1 - (t -= 2) * t) + 1);
+}
+
+export function circIn(t) {
+	return 1.0 - Math.sqrt(1.0 - t * t);
+}
+
+export function circOut(t) {
+	return Math.sqrt(1 - --t * t);
+}
+
+export function cubicInOut(t) {
+	return t < 0.5 ? 4.0 * t * t * t : 0.5 * Math.pow(2.0 * t - 2.0, 3.0) + 1.0;
+}
+
+export function cubicIn(t) {
+	return t * t * t;
+}
+
+export function cubicOut(t) {
+	var f = t - 1.0;
+	return f * f * f + 1.0;
+}
+
+export function elasticInOut(t) {
+	return t < 0.5
+		? 0.5 *
+				Math.sin(((+13.0 * Math.PI) / 2) * 2.0 * t) *
+				Math.pow(2.0, 10.0 * (2.0 * t - 1.0))
+		: 0.5 *
+				Math.sin(((-13.0 * Math.PI) / 2) * (2.0 * t - 1.0 + 1.0)) *
+				Math.pow(2.0, -10.0 * (2.0 * t - 1.0)) +
+				1.0;
+}
+
+export function elasticIn(t) {
+	return Math.sin((13.0 * t * Math.PI) / 2) * Math.pow(2.0, 10.0 * (t - 1.0));
+}
+
+export function elasticOut(t) {
+	return (
+		Math.sin((-13.0 * (t + 1.0) * Math.PI) / 2) * Math.pow(2.0, -10.0 * t) + 1.0
+	);
+}
+
+export function expoInOut(t) {
+	return t === 0.0 || t === 1.0
+		? t
+		: t < 0.5
+		? +0.5 * Math.pow(2.0, 20.0 * t - 10.0)
+		: -0.5 * Math.pow(2.0, 10.0 - t * 20.0) + 1.0;
+}
+
+export function expoIn(t) {
+	return t === 0.0 ? t : Math.pow(2.0, 10.0 * (t - 1.0));
+}
+
+export function expoOut(t) {
+	return t === 1.0 ? t : 1.0 - Math.pow(2.0, -10.0 * t);
+}
+
+export function linear(t) {
+	return t;
+}
+
+export function quadInOut(t) {
+	t /= 0.5;
+	if (t < 1) return 0.5 * t * t;
+	t--;
+	return -0.5 * (t * (t - 2) - 1);
+}
+
+export function quadIn(t) {
+	return t * t;
+}
+
+export function quadOut(t) {
+	return -t * (t - 2.0);
+}
+
+export function quarticInOut(t) {
+	return t < 0.5
+		? +8.0 * Math.pow(t, 4.0)
+		: -8.0 * Math.pow(t - 1.0, 4.0) + 1.0;
+}
+
+export function quarticIn(t) {
+	return Math.pow(t, 4.0);
+}
+
+export function quarticOut(t) {
+	return Math.pow(t - 1.0, 3.0) * (1.0 - t) + 1.0;
+}
+
+export function qinticInOut(t) {
+	if ((t *= 2) < 1) return 0.5 * t * t * t * t * t;
+	return 0.5 * ((t -= 2) * t * t * t * t + 2);
+}
+
+export function qinticIn(t) {
+	return t * t * t * t * t;
+}
+
+export function qinticOut(t) {
+	return --t * t * t * t * t + 1;
+}
+
+export function sineInOut(t) {
+	return -0.5 * (Math.cos(Math.PI * t) - 1);
+}
+
+export function sineIn(t) {
+	var v = Math.cos(t * Math.PI * 0.5);
+	if (Math.abs(v) < 1e-14) return 1;
+	else return 1 - v;
+}
+
+export function sineOut(t) {
+	return Math.sin((t * Math.PI) / 2);
+}
diff --git a/rollup.config.js b/rollup.config.js
index 1bb01c928..7e1947ec4 100644
--- a/rollup.config.js
+++ b/rollup.config.js
@@ -52,16 +52,6 @@ export default [
 		experimentalCodeSplitting: true
 	},
 
-	/* index.js */
-	{
-		input: 'index.mjs',
-		output: {
-			file: 'index.js',
-			format: 'cjs'
-		},
-		external: name => name !== 'index.mjs'
-	},
-
 	/* internal.[m]js */
 	{
 		input: 'src/internal/index.js',
@@ -77,13 +67,13 @@ export default [
 		]
 	},
 
-	/* store.js */
-	{
-		input: 'store.mjs',
+	// runtime API
+	...['index', 'store', 'easing', 'transition'].map(name => ({
+		input: `${name}.mjs`,
 		output: {
-			file: 'store.js',
+			file: `${name}.js`,
 			format: 'cjs'
 		},
-		external: name => name !== 'store.mjs'
-	},
+		external: id => id !== `${name}.mjs`
+	}))
 ];
diff --git a/transition.mjs b/transition.mjs
new file mode 100644
index 000000000..1b6fbec60
--- /dev/null
+++ b/transition.mjs
@@ -0,0 +1,82 @@
+import { cubicOut, cubicInOut } from './easing';
+
+export function fade(node, {
+	delay = 0,
+	duration = 400
+}) {
+	const o = +getComputedStyle(node).opacity;
+
+	return {
+		delay,
+		duration,
+		css: t => `opacity: ${t * o}`
+	};
+}
+
+export function fly(node, {
+	delay = 0,
+	duration = 400,
+	easing = cubicOut,
+	x = 0,
+	y = 0
+}) {
+	const style = getComputedStyle(node);
+	const opacity = +style.opacity;
+	const transform = style.transform === 'none' ? '' : style.transform;
+
+	return {
+		delay,
+		duration,
+		easing,
+		css: t => `
+			transform: ${transform} translate(${(1 - t) * x}px, ${(1 - t) * y}px);
+			opacity: ${t * opacity}`
+	};
+}
+
+export function slide(node, {
+	delay = 0,
+	duration = 400,
+	easing = cubicOut
+}) {
+	const style = getComputedStyle(node);
+	const opacity = +style.opacity;
+	const height = parseFloat(style.height);
+	const padding_top = parseFloat(style.paddingTop);
+	const padding_bottom = parseFloat(style.paddingBottom);
+	const margin_top = parseFloat(style.marginTop);
+	const margin_bottom = parseFloat(style.marginBottom);
+	const border_top_width = parseFloat(style.borderTopWidth);
+	const border_bottom_width = parseFloat(style.borderBottomWidth);
+
+	return {
+		delay,
+		duration,
+		easing,
+		css: t =>
+			`overflow: hidden;` +
+			`opacity: ${Math.min(t * 20, 1) * opacity};` +
+			`height: ${t * height}px;` +
+			`padding-top: ${t * padding_top}px;` +
+			`padding-bottom: ${t * padding_bottom}px;` +
+			`margin-top: ${t * margin_top}px;` +
+			`margin-bottom: ${t * margin_bottom}px;` +
+			`border-top-width: ${t * border_top_width}px;` +
+			`border-bottom-width: ${t * border_bottom_width}px;`
+	};
+}
+
+export function draw(node, {
+	delay = 0,
+	duration = 800,
+	easing = cubicInOut
+}) {
+	const len = node.getTotalLength();
+
+	return {
+		delay,
+		duration,
+		easing,
+		css: (t, u) => `stroke-dasharray: ${t * len} ${u * len}`
+	};
+}
\ No newline at end of file