diff --git a/LICENSE.md b/LICENSE.md
index 238cabc51..7e7143837 100644
--- a/LICENSE.md
+++ b/LICENSE.md
@@ -50,6 +50,28 @@ License: MIT
 By: Rich Harris
 Repository: rollup/plugins
 
+> The MIT License (MIT)
+> 
+> Copyright (c) 2019 RollupJS Plugin Contributors (https://github.com/rollup/plugins/graphs/contributors)
+> 
+> Permission is hereby granted, free of charge, to any person obtaining a copy
+> of this software and associated documentation files (the "Software"), to deal
+> in the Software without restriction, including without limitation the rights
+> to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+> copies of the Software, and to permit persons to whom the Software is
+> furnished to do so, subject to the following conditions:
+> 
+> The above copyright notice and this permission notice shall be included in
+> all copies or substantial portions of the Software.
+> 
+> THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+> IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+> FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+> AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+> LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+> OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+> THE SOFTWARE.
+
 ---------------------------------------
 
 ## anymatch
diff --git a/docs/repl/components/OutputStatus.vue b/docs/repl/components/OutputStatus.vue
index f71f52210..8f3d28751 100644
--- a/docs/repl/components/OutputStatus.vue
+++ b/docs/repl/components/OutputStatus.vue
@@ -1,19 +1,37 @@
 <template>
 	<div
 		class="status"
-		:class="waiting ? 'waiting' : error ? 'error' : warnings.length > 0 ? 'warnings' : 'success'"
+		:class="
+			waiting
+				? 'waiting'
+				: error
+				  ? 'error'
+				  : hasWarnings
+				    ? 'warnings'
+				    : logs.length > 0
+				      ? 'logs'
+				      : 'success'
+		"
 	>
 		<span v-if="waiting">
 			<span class="repl-icon-attention"></span>
 			Loading Rollup...
 		</span>
 		<StatusMessage v-else-if="error" :message="error" isError />
-		<span v-else-if="warnings.length > 0">
+		<span v-else-if="hasWarnings">
 			<span class="repl-icon-attention" />
 			Rollup completed with warnings:
-			<ul class="warning-list">
-				<li v-for="(warning, i) in warnings" :key="i" class="warning">
-					<StatusMessage :message="warning" />
+			<ul class="log-list">
+				<li v-for="([, log], i) in logs" :key="i" class="log">
+					<StatusMessage :message="log" />
+				</li>
+			</ul>
+		</span>
+		<span v-else-if="logs.length > 0">
+			Rollup completed with logs:
+			<ul class="log-list">
+				<li v-for="([, log], i) in logs" :key="i" class="log">
+					<StatusMessage :message="log" />
 				</li>
 			</ul>
 		</span>
@@ -26,6 +44,7 @@
 
 <script setup lang="ts">
 import { computed } from 'vue';
+import { LOGLEVEL_WARN } from '../../../src/utils/logging';
 import { useRollup } from '../stores/rollup';
 import { useRollupOutput } from '../stores/rollupOutput';
 import StatusMessage from './StatusMessage.vue';
@@ -35,7 +54,8 @@ const rollupOutputStore = useRollupOutput();
 
 const waiting = computed(() => !(rollupStore.loaded.instance || rollupStore.loaded.error));
 const error = computed(() => rollupOutputStore.output.error);
-const warnings = computed(() => rollupOutputStore.output.warnings);
+const logs = computed(() => rollupOutputStore.output.logs);
+const hasWarnings = computed(() => logs.value.some(([level]) => level === LOGLEVEL_WARN));
 </script>
 
 <style scoped>
@@ -62,7 +82,12 @@ const warnings = computed(() => rollupOutputStore.output.warnings);
 	color: var(--warning-color);
 }
 
-.warning {
+.logs {
+	background-color: var(--log-background);
+	color: var(--log-color);
+}
+
+.log {
 	margin-top: 16px;
 }
 
@@ -75,7 +100,7 @@ const warnings = computed(() => rollupOutputStore.output.warnings);
 	font-size: 1em;
 }
 
-.warning-list {
+.log-list {
 	list-style-type: none;
 	padding-inline-start: 0;
 	margin-top: 10px;
diff --git a/docs/repl/components/ReplEditor.vue b/docs/repl/components/ReplEditor.vue
index 6cc3b7e47..13c175efe 100644
--- a/docs/repl/components/ReplEditor.vue
+++ b/docs/repl/components/ReplEditor.vue
@@ -5,8 +5,9 @@
 <script setup lang="ts">
 import type { EditorView } from '@codemirror/view';
 import { onMounted, onUnmounted, ref, watch } from 'vue';
-import type { RollupLog } from '../../../src/rollup/types';
-import type { AddWarnings } from '../helpers/editor';
+import type { LogLevel, RollupLog } from '../../../src/rollup/types';
+import { LOGLEVEL_ERROR } from '../../../src/utils/logging';
+import type { AddLogs } from '../helpers/editor';
 import { getFileNameFromMessage } from '../helpers/messages';
 import { useRollupOutput } from '../stores/rollupOutput';
 
@@ -18,14 +19,14 @@ const properties = defineProps<{
 }>();
 // eslint-disable-next-line @typescript-eslint/no-unused-vars
 const emit = defineEmits<{ (event: 'update:code', code: string): void }>();
-let addWarningsEffect: AddWarnings;
+let addLogsEffect: AddLogs;
 let editor: EditorView;
 // eslint-disable-next-line vue/no-setup-props-destructure
 let previousCode = properties.code;
 
 onMounted(async () => {
-	const { createEditor, addWarnings } = await import('../helpers/editor');
-	addWarningsEffect = addWarnings;
+	const { createEditor, addLogs } = await import('../helpers/editor');
+	addLogsEffect = addLogs;
 	editor = createEditor(
 		// eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 		editorContainer.value!,
@@ -52,24 +53,24 @@ onMounted(async () => {
 	);
 
 	if (properties.moduleName && !properties.readonly) {
-		const addMarkers = (messages: RollupLog[], type: 'warning' | 'error') => {
+		const addMarkers = (messages: [LogLevel | 'error', RollupLog][]) => {
 			const relevantMessages = messages.filter(
-				(message): message is RollupLog & { pos: number } =>
-					typeof message.pos === 'number' &&
-					getFileNameFromMessage(message) === `/${properties.moduleName}`
+				(message): message is [LogLevel | 'error', RollupLog & { pos: number }] =>
+					typeof message[1].pos === 'number' &&
+					getFileNameFromMessage(message[1]) === `/${properties.moduleName}`
 			);
-			editor.dispatch({ effects: [addWarningsEffect.of({ messages: relevantMessages, type })] });
+			editor.dispatch({ effects: [addLogsEffect.of({ messages: relevantMessages })] });
 		};
 
 		const outputStore = useRollupOutput();
 
 		watch(
 			() => outputStore.output,
-			({ error, warnings }) => {
+			({ error, logs }) => {
 				if (error) {
-					addMarkers([error], 'error');
+					addMarkers([[LOGLEVEL_ERROR, error]]);
 				} else {
-					addMarkers(warnings, 'warning');
+					addMarkers(logs);
 				}
 			}
 		);
diff --git a/docs/repl/components/ReplMain.vue b/docs/repl/components/ReplMain.vue
index 4d4d0e059..c70a6735b 100644
--- a/docs/repl/components/ReplMain.vue
+++ b/docs/repl/components/ReplMain.vue
@@ -141,6 +141,8 @@ h2 {
 
 .repl {
 	height: calc(100% - 3.6em);
+	--log-color: #181818;
+	--log-background: #80bdff;
 	--warning-color: #181818;
 	--warning-background: #eed245;
 	--error-color: white;
diff --git a/docs/repl/helpers/editor.ts b/docs/repl/helpers/editor.ts
index bae64f886..576a548fd 100644
--- a/docs/repl/helpers/editor.ts
+++ b/docs/repl/helpers/editor.ts
@@ -7,37 +7,36 @@ import { EditorState, StateEffect, StateField } from '@codemirror/state';
 import type { ViewUpdate } from '@codemirror/view';
 import { Decoration, dropCursor, EditorView, keymap, lineNumbers } from '@codemirror/view';
 import { tags } from '@lezer/highlight';
+import type { LogLevel } from '../../../src/rollup/types';
 
-export type AddWarnings = StateEffectType<{
-	messages: { message: string; pos: number }[];
-	type: 'error' | 'warning';
+export type AddLogs = StateEffectType<{
+	messages: [level: LogLevel | 'error', { message: string; pos: number }][];
 }>;
 
-export const addWarnings: AddWarnings = StateEffect.define<{
-	messages: { message: string; pos: number }[];
-	type: 'error' | 'warning';
+export const addLogs: AddLogs = StateEffect.define<{
+	messages: [level: LogLevel | 'error', { message: string; pos: number }][];
 }>();
 
-const warningsField = StateField.define({
+const logsField = StateField.define({
 	create() {
 		return Decoration.none;
 	},
 	provide: field => EditorView.decorations.from(field),
-	update(warnings, transaction) {
-		let hasWarning = false;
+	update(logs, transaction) {
+		let hasLog = false;
 		for (const effect of transaction.effects) {
-			if (effect.is(addWarnings)) {
-				if (!hasWarning) {
-					hasWarning = true;
-					warnings = Decoration.none;
+			if (effect.is(addLogs)) {
+				if (!hasLog) {
+					hasLog = true;
+					logs = Decoration.none;
 				}
-				warnings = warnings.update({
+				logs = logs.update({
 					add: effect.value.messages
-						.sort((a, b) => a.pos - b.pos)
-						.map(({ pos, message }) =>
+						.sort((a, b) => a[1].pos - b[1].pos)
+						.map(([level, { pos, message }]) =>
 							Decoration.mark({
 								attributes: {
-									class: `cm-rollup-${effect.value.type}`,
+									class: `cm-rollup-${level}`,
 									title: message
 								}
 							}).range(pos, pos + 1)
@@ -45,7 +44,7 @@ const warningsField = StateField.define({
 				});
 			}
 		}
-		return warnings;
+		return logs;
 	}
 });
 
@@ -86,15 +85,33 @@ const theme = EditorView.baseTheme({
 	},
 	'.cm-rollup-error': {
 		backgroundColor: 'var(--error-background)',
+		borderRadius: '2px',
 		color: 'var(--error-color)',
-		margin: '-1px',
-		padding: '1px'
+		margin: '-2px',
+		padding: '2px'
 	},
-	'.cm-rollup-warning': {
+	'.cm-rollup-error > span': {
+		color: 'var(--error-color)'
+	},
+	'.cm-rollup-info': {
+		backgroundColor: 'var(--log-background)',
+		borderRadius: '2px',
+		color: 'var(--log-color)',
+		margin: '-2px',
+		padding: '2px'
+	},
+	'.cm-rollup-info > span': {
+		color: 'var(--log-color)'
+	},
+	'.cm-rollup-warn': {
 		backgroundColor: 'var(--warning-background)',
+		borderRadius: '2px',
 		color: 'var(--warning-color)',
-		margin: '-1px',
-		padding: '1px'
+		margin: '-2px',
+		padding: '2px'
+	},
+	'.cm-rollup-warn > span': {
+		color: 'var(--warning-color)'
 	},
 	'.cm-scroller': {
 		borderBottomLeftRadius: '8px',
@@ -153,7 +170,7 @@ export const createEditor = (
 			EditorView.lineWrapping,
 			EditorState.tabSize.of(2),
 			EditorView.updateListener.of(onUpdate as any),
-			warningsField,
+			logsField,
 			theme
 		],
 		parent
diff --git a/docs/repl/stores/options.ts b/docs/repl/stores/options.ts
index 20057c600..f1698b2fd 100644
--- a/docs/repl/stores/options.ts
+++ b/docs/repl/stores/options.ts
@@ -122,6 +122,9 @@ export const useOptions = defineStore('options2', () => {
 		defaultValue: 'undefined',
 		name: 'context'
 	});
+	const optionExperimentalLogSideEffects = getBoolean({
+		name: 'experimentalLogSideEffects'
+	});
 	const optionOutputAmdAutoId = getBoolean({
 		available: () => isAmdFormat.value,
 		name: 'output.amd.autoId'
@@ -402,6 +405,7 @@ export const useOptions = defineStore('options2', () => {
 
 	const optionList: OptionType[] = [
 		optionContext,
+		optionExperimentalLogSideEffects,
 		optionOutputAmdAutoId,
 		optionOutputAmdBasePath,
 		optionOutputAmdDefine,
diff --git a/docs/repl/stores/rollupOutput.ts b/docs/repl/stores/rollupOutput.ts
index 1c858cfee..f3cfaf7be 100644
--- a/docs/repl/stores/rollupOutput.ts
+++ b/docs/repl/stores/rollupOutput.ts
@@ -1,6 +1,7 @@
 import { defineStore } from 'pinia';
 import { ref, watch } from 'vue';
 import type {
+	LogLevel,
 	OutputOptions,
 	RollupError,
 	RollupLog,
@@ -18,8 +19,8 @@ import { useRollup } from './rollup';
 interface GeneratedRollupOutput {
 	error: RollupError | null;
 	externalImports: string[];
+	logs: [LogLevel, RollupLog][];
 	output: RollupOutput['output'] | never[];
-	warnings: RollupLog[];
 }
 
 interface BundleRequest {
@@ -55,15 +56,14 @@ async function bundle({ rollup: { instance }, modules, options, setOutput }: Bun
 		modulesById.set(module.name, module);
 	}
 
-	const warnings: RollupLog[] = [];
+	const logs: [LogLevel, RollupLog][] = [];
 	const externalImports = new Set<string>();
 
 	const rollupOptions: RollupOptions = {
 		...options,
 		input: modules.filter((module, index) => index === 0 || module.isEntry).map(({ name }) => name),
-		onwarn(warning) {
-			warnings.push(warning);
-			logWarning(warning);
+		onLog(level, log) {
+			logs.push([level, log]);
 		},
 		plugins: [
 			{
@@ -105,8 +105,8 @@ async function bundle({ rollup: { instance }, modules, options, setOutput }: Bun
 		setOutput({
 			error: null,
 			externalImports: [...externalImports].sort((a, b) => (a < b ? -1 : 1)),
-			output: generated.output,
-			warnings
+			logs,
+			output: generated.output
 		});
 	} catch (error) {
 		console.log(
@@ -115,7 +115,7 @@ async function bundle({ rollup: { instance }, modules, options, setOutput }: Bun
 			error,
 			JSON.parse(JSON.stringify(error))
 		);
-		setOutput({ error: error as Error, externalImports: [], output: [], warnings });
+		setOutput({ error: error as Error, externalImports: [], logs, output: [] });
 		logWarning(error as Error);
 	}
 	console.groupEnd();
@@ -128,8 +128,8 @@ export const useRollupOutput = defineStore('rollupOutput', () => {
 	const output = ref<GeneratedRollupOutput>({
 		error: null,
 		externalImports: [],
-		output: [],
-		warnings: []
+		logs: [],
+		output: []
 	});
 	let bundleDebounceTimeout: ReturnType<typeof setTimeout> | undefined;
 	let nextBundleRequest: BundleRequest | null = null;
@@ -148,8 +148,8 @@ export const useRollupOutput = defineStore('rollupOutput', () => {
 			bundleRequest.setOutput({
 				error: bundleRequest.rollup.error,
 				externalImports: [],
-				output: [],
-				warnings: []
+				logs: [],
+				output: []
 			});
 			return;
 		}