diff --git a/src/lib/auth-redirect.test.ts b/src/lib/auth-redirect.test.ts
index 710e032..5de1b18 100644
--- a/src/lib/auth-redirect.test.ts
+++ b/src/lib/auth-redirect.test.ts
@@ -16,11 +16,14 @@ describe('safeRedirectPath', () => {
 });
 
 describe('readPostAuthRedirectUrl', () => {
-	it('prefers redirect_url and supports redirectUrl', () => {
+	it('prefers redirect_url and supports Clerk redirect params', () => {
 		expect(readPostAuthRedirectUrl(new URLSearchParams('redirect_url=/runs'))).toBe('/runs');
 		expect(readPostAuthRedirectUrl(new URLSearchParams('redirectUrl=/regression'))).toBe(
 			'/regression'
 		);
+		expect(readPostAuthRedirectUrl(new URLSearchParams('redirectAfterAuth=/runs/123'))).toBe(
+			'/runs/123'
+		);
 	});
 
 	it('falls back when params are missing or unsafe', () => {
diff --git a/src/lib/auth-redirect.ts b/src/lib/auth-redirect.ts
index aa3233c..2d2ed6c 100644
--- a/src/lib/auth-redirect.ts
+++ b/src/lib/auth-redirect.ts
@@ -1,6 +1,9 @@
-const defaultPostAuthPath = '/runs';
+const defaultPostAuthPath: `/${string}` = '/runs';
 
-export function safeRedirectPath(path: string | null | undefined, fallback = defaultPostAuthPath) {
+export function safeRedirectPath(
+	path: string | null | undefined,
+	fallback: `/${string}` = defaultPostAuthPath
+): `/${string}` {
 	if (
 		!path ||
 		!path.startsWith('/') ||
@@ -10,13 +13,16 @@ export function safeRedirectPath(path: string | null | undefined, fallback = def
 	) {
 		return fallback;
 	}
-	return path;
+	return path as `/${string}`;
 }
 
 export function readPostAuthRedirectUrl(
 	searchParams: URLSearchParams,
-	fallback = defaultPostAuthPath
+	fallback: `/${string}` = defaultPostAuthPath
 ) {
-	const raw = searchParams.get('redirect_url') ?? searchParams.get('redirectUrl');
+	const raw =
+		searchParams.get('redirect_url') ??
+		searchParams.get('redirectUrl') ??
+		searchParams.get('redirectAfterAuth');
 	return safeRedirectPath(raw, fallback);
 }
diff --git a/src/lib/components/post-auth-redirect.svelte b/src/lib/components/post-auth-redirect.svelte
new file mode 100644
index 0000000..1ca5cb2
--- /dev/null
+++ b/src/lib/components/post-auth-redirect.svelte
@@ -0,0 +1,10 @@
+<script lang="ts">
+	import { base } from '$app/paths';
+	import { onMount } from 'svelte';
+
+	let { to }: { to: `/${string}` } = $props();
+
+	onMount(() => {
+		window.location.replace(`${base}${to}`);
+	});
+</script>
diff --git a/src/lib/server/auth.ts b/src/lib/server/auth.ts
index 30f7d27..991d3a0 100644
--- a/src/lib/server/auth.ts
+++ b/src/lib/server/auth.ts
@@ -5,7 +5,7 @@ import { error, redirect, type RequestEvent } from '@sveltejs/kit';
 
 export { safeRedirectPath } from '$lib/auth-redirect';
 
-export function readPostAuthRedirectUrl(event: RequestEvent, fallback?: string) {
+export function readPostAuthRedirectUrl(event: RequestEvent, fallback?: `/${string}`) {
 	return readPostAuthRedirectUrlFromSearchParams(event.url.searchParams, fallback);
 }
 
diff --git a/src/routes/(marketing)/sign-in/+page.svelte b/src/routes/(marketing)/sign-in/+page.svelte
index 2b9d300..0d3e6b4 100644
--- a/src/routes/(marketing)/sign-in/+page.svelte
+++ b/src/routes/(marketing)/sign-in/+page.svelte
@@ -1,6 +1,7 @@
 <script lang="ts">
 	import { page } from '$app/state';
 	import AuthWidgetLoading from '$lib/components/auth-widget-loading.svelte';
+	import PostAuthRedirect from '$lib/components/post-auth-redirect.svelte';
 	import ClerkLoaded from 'clerk-sveltekit/client/ClerkLoaded.svelte';
 	import ClerkLoading from 'clerk-sveltekit/client/ClerkLoading.svelte';
 	import SignIn from 'clerk-sveltekit/client/SignIn.svelte';
@@ -8,7 +9,9 @@
 
 	const redirectUrl = $derived(
 		safeRedirectPath(
-			page.url.searchParams.get('redirect_url') ?? page.url.searchParams.get('redirectUrl')
+			page.url.searchParams.get('redirect_url') ??
+				page.url.searchParams.get('redirectUrl') ??
+				page.url.searchParams.get('redirectAfterAuth')
 		)
 	);
 </script>
@@ -26,8 +29,13 @@
 		<ClerkLoading>
 			<AuthWidgetLoading />
 		</ClerkLoading>
-		<ClerkLoaded>
-			<SignIn {redirectUrl} signUpUrl="/sign-up" />
+		<ClerkLoaded let:clerk>
+			{#if clerk?.user}
+				<PostAuthRedirect to={redirectUrl} />
+				<AuthWidgetLoading />
+			{:else}
+				<SignIn {redirectUrl} signUpUrl="/sign-up" />
+			{/if}
 		</ClerkLoaded>
 	</section>
 </main>