diff --git a/.changeset/friendly-monkeys-grab.md b/.changeset/friendly-monkeys-grab.md
new file mode 100644
index 000000000..ea87d8882
--- /dev/null
+++ b/.changeset/friendly-monkeys-grab.md
@@ -0,0 +1,6 @@
+---
+'@getodk/web-forms': minor
+---
+
+- Emit submission payload when subscribed to `submit` event
+- Emit chunked submission payload when subscribed to new `submitChunked` event
diff --git a/.changeset/strange-needles-compare.md b/.changeset/strange-needles-compare.md
new file mode 100644
index 000000000..6328fd49f
--- /dev/null
+++ b/.changeset/strange-needles-compare.md
@@ -0,0 +1,5 @@
+---
+'@getodk/xforms-engine': patch
+---
+
+Fix: correct types for chunked/monolithic submission result
diff --git a/packages/scenario/src/jr/Scenario.ts b/packages/scenario/src/jr/Scenario.ts
index 5387affcd..991c8fd3c 100644
--- a/packages/scenario/src/jr/Scenario.ts
+++ b/packages/scenario/src/jr/Scenario.ts
@@ -7,9 +7,6 @@ import type {
 	RepeatRangeUncontrolledNode,
 	RootNode,
 	SelectNode,
-	SubmissionChunkedType,
-	SubmissionOptions,
-	SubmissionResult,
 } from '@getodk/xforms-engine';
 import { constants as ENGINE_CONSTANTS } from '@getodk/xforms-engine';
 import type { Accessor, Setter } from 'solid-js';
@@ -965,10 +962,8 @@ export class Scenario {
 	 * more about Collect's responsibility for submission (beyond serialization,
 	 * already handled by {@link proposed_serializeInstance}).
 	 */
-	prepareWebFormsSubmission<ChunkedType extends SubmissionChunkedType>(
-		options?: SubmissionOptions<ChunkedType>
-	): Promise<SubmissionResult<ChunkedType>> {
-		return this.instanceRoot.prepareSubmission<ChunkedType>(options);
+	prepareWebFormsSubmission() {
+		return this.instanceRoot.prepareSubmission();
 	}
 
 	// TODO: consider adapting tests which use the following interfaces to use
diff --git a/packages/web-forms/src/components/OdkWebForm.vue b/packages/web-forms/src/components/OdkWebForm.vue
index 9ee41ee84..e06d01d2a 100644
--- a/packages/web-forms/src/components/OdkWebForm.vue
+++ b/packages/web-forms/src/components/OdkWebForm.vue
@@ -1,10 +1,15 @@
 <script setup lang="ts">
-import type { MissingResourceBehavior } from '@getodk/xforms-engine';
+import type {
+	ChunkedSubmissionResult,
+	MissingResourceBehavior,
+	MonolithicSubmissionResult,
+} from '@getodk/xforms-engine';
 import { initializeForm, type FetchFormAttachment, type RootNode } from '@getodk/xforms-engine';
 import Button from 'primevue/button';
 import Card from 'primevue/card';
 import PrimeMessage from 'primevue/message';
-import { computed, provide, reactive, ref, watchEffect, type ComponentPublicInstance } from 'vue';
+import type { ComponentPublicInstance } from 'vue';
+import { computed, getCurrentInstance, provide, reactive, ref, watchEffect } from 'vue';
 import { FormInitializationError } from '../lib/error/FormInitializationError.ts';
 import FormLoadFailureDialog from './Form/FormLoadFailureDialog.vue';
 import FormHeader from './FormHeader.vue';
@@ -12,12 +17,91 @@ import QuestionList from './QuestionList.vue';
 
 const webFormsVersion = __WEB_FORMS_VERSION__;
 
-const props = defineProps<{
+interface OdkWebFormsProps {
 	formXml: string;
 	fetchFormAttachment: FetchFormAttachment;
 	missingResourceBehavior?: MissingResourceBehavior;
-}>();
-const emit = defineEmits(['submit']);
+
+	/**
+	 * Note: this parameter must be set when subscribing to the
+	 * {@link OdkWebFormEmits.submitChunked | submitChunked} event.
+	 */
+	submissionMaxSize?: number;
+}
+
+const props = defineProps<OdkWebFormsProps>();
+
+// eslint-disable-next-line @typescript-eslint/consistent-type-definitions -- evidently a type must be used for this to be assigned to a name (which we use!); as an interface, it won't satisfy the `Record` constraint of `defineEmits`.
+type OdkWebFormEmits = {
+	submit: [submissionPayload: MonolithicSubmissionResult];
+	submitChunked: [submissionPayload: ChunkedSubmissionResult];
+};
+
+/**
+ * Supports {@link isEmitSubscribed}.
+ *
+ * @see
+ * {@link https://mokkapps.de/vue-tips/check-if-component-has-event-listener-attached}
+ *
+ * Usage here is intentionally different from the linked article: for reasons
+ * unknown, {@link getCurrentInstance} returns `null` called in a
+ * {@link computed} function body (or any function body), but produces the
+ * expected value assigned to a top level value as it is here.
+ */
+const instance = getCurrentInstance();
+
+type OdkWebFormEmitsEventType = keyof OdkWebFormEmits;
+
+/**
+ * A Vue _template_ event handler is subscribed with syntax like:
+ *
+ * ```vue
+ * <OdkWebForm @whatever-event-type="handler" />
+ * ```
+ *
+ * At runtime, its props key is a concatenation of the prefix "on" and the
+ * PascalCase variant of the same event type. Since we already
+ * {@link defineEmits} in camelCase, this type represents that key format.
+ */
+type EventKey = `on${Capitalize<OdkWebFormEmitsEventType>}`;
+
+/**
+ * @see {@link https://mokkapps.de/vue-tips/check-if-component-has-event-listener-attached}
+ * @see {@link instance}
+ * @see {@link EventKey}
+ */
+const isEmitSubscribed = (eventKey: EventKey): boolean => {
+	return eventKey in (instance?.vnode.props ?? {});
+};
+
+const emitSubmit = async (root: RootNode) => {
+	if (isEmitSubscribed('onSubmit')) {
+		const payload = await root.prepareSubmission({
+			chunked: 'monolithic',
+		});
+
+		emit('submit', payload);
+	}
+};
+
+const emitSubmitChunked = async (root: RootNode) => {
+	if (isEmitSubscribed('onSubmitChunked')) {
+		const maxSize = props.submissionMaxSize;
+
+		if (maxSize == null) {
+			throw new Error('The `submissionMaxSize` prop is required for chunked submissions');
+		}
+
+		const payload = await root.prepareSubmission({
+			chunked: 'chunked',
+			maxSize,
+		});
+
+		emit('submitChunked', payload);
+	}
+};
+
+const emit = defineEmits<OdkWebFormEmits>();
 
 const odkForm = ref<RootNode>();
 const submitPressed = ref(false);
@@ -38,8 +122,13 @@ initializeForm(props.formXml, {
 	});
 
 const handleSubmit = () => {
-	if (odkForm.value?.validationState.violations?.length === 0) {
-		emit('submit');
+	const root = odkForm.value;
+
+	if (root?.validationState.violations?.length === 0) {
+		// eslint-disable-next-line @typescript-eslint/no-floating-promises
+		emitSubmit(root);
+		// eslint-disable-next-line @typescript-eslint/no-floating-promises
+		emitSubmitChunked(root);
 	} else {
 		submitPressed.value = true;
 		document.scrollingElement?.scrollTo(0, 0);
diff --git a/packages/web-forms/src/demo/FormPreview.vue b/packages/web-forms/src/demo/FormPreview.vue
index 506c66a72..3140614bd 100644
--- a/packages/web-forms/src/demo/FormPreview.vue
+++ b/packages/web-forms/src/demo/FormPreview.vue
@@ -1,6 +1,11 @@
 <script setup lang="ts">
 import { xformFixturesByCategory, XFormResource } from '@getodk/common/fixtures/xforms.ts';
-import type { FetchFormAttachment, MissingResourceBehavior } from '@getodk/xforms-engine';
+import type {
+	ChunkedSubmissionResult,
+	FetchFormAttachment,
+	MissingResourceBehavior,
+	MonolithicSubmissionResult,
+} from '@getodk/xforms-engine';
 import { constants as ENGINE_CONSTANTS } from '@getodk/xforms-engine';
 import { ref } from 'vue';
 import { useRoute } from 'vue-router';
@@ -50,9 +55,17 @@ xformResource
 		alert('Failed to load the Form XML');
 	});
 
-const handleSubmit = () => {
+const handleSubmit = (payload: MonolithicSubmissionResult) => {
+	// eslint-disable-next-line no-console
+	console.log('submission payload:', payload);
+
 	alert(`Submit button was pressed`);
 };
+
+const handleSubmitChunked = (payload: ChunkedSubmissionResult) => {
+	// eslint-disable-next-line no-console
+	console.log('CHUNKED submission payload:', payload);
+};
 </script>
 <template>
 	<template v-if="formPreviewState">
@@ -60,7 +73,9 @@ const handleSubmit = () => {
 			:form-xml="formPreviewState.formXML"
 			:fetch-form-attachment="formPreviewState.fetchFormAttachment"
 			:missing-resource-behavior="formPreviewState.missingResourceBehavior"
+			:submission-max-size="Infinity"
 			@submit="handleSubmit"
+			@submit-chunked="handleSubmitChunked"
 		/>
 		<FeedbackButton />
 	</template>
diff --git a/packages/xforms-engine/src/client/RootNode.ts b/packages/xforms-engine/src/client/RootNode.ts
index 5e3dcffca..a4e60d980 100644
--- a/packages/xforms-engine/src/client/RootNode.ts
+++ b/packages/xforms-engine/src/client/RootNode.ts
@@ -3,8 +3,12 @@ import type { RootDefinition } from '../parse/model/RootDefinition.ts';
 import type { BaseNode, BaseNodeState } from './BaseNode.ts';
 import type { ActiveLanguage, FormLanguage, FormLanguages } from './FormLanguage.ts';
 import type { GeneralChildNode } from './hierarchy.ts';
-import type { SubmissionChunkedType, SubmissionOptions } from './submission/SubmissionOptions.ts';
-import type { SubmissionResult } from './submission/SubmissionResult.ts';
+import type { SubmissionOptions } from './submission/SubmissionOptions.ts';
+import type {
+	ChunkedSubmissionResult,
+	MonolithicSubmissionResult,
+	SubmissionResult,
+} from './submission/SubmissionResult.ts';
 import type { AncestorNodeValidationState } from './validation.ts';
 
 export interface RootNodeState extends BaseNodeState {
@@ -84,7 +88,7 @@ export interface RootNode extends BaseNode {
 	 * A client may specify {@link SubmissionOptions<'chunked'>}, in which case a
 	 * {@link SubmissionResult<'chunked'>} will be produced, with form attachments
 	 */
-	prepareSubmission<ChunkedType extends SubmissionChunkedType>(
-		options?: SubmissionOptions<ChunkedType>
-	): Promise<SubmissionResult<ChunkedType>>;
+	prepareSubmission(): Promise<MonolithicSubmissionResult>;
+	prepareSubmission(options: SubmissionOptions<'monolithic'>): Promise<MonolithicSubmissionResult>;
+	prepareSubmission(options: SubmissionOptions<'chunked'>): Promise<ChunkedSubmissionResult>;
 }