diff --git a/src/app/api/like/route.ts b/src/app/api/like/route.ts
new file mode 100644
index 0000000..47dbf95
--- /dev/null
+++ b/src/app/api/like/route.ts
@@ -0,0 +1,61 @@
+import { auth } from "@/lib/auth";
+import { prisma } from "@/lib/prisma";
+
+export async function PATCH(request: Request) {
+	// todo: rate limit
+
+	const session = await auth();
+	if (!session) return Response.json({ error: "Unauthorized" }, { status: 401 });
+
+	const { miiId } = await request.json();
+	if (!miiId) return Response.json({ error: "Mii ID is required" }, { status: 400 });
+
+	const result = await prisma.$transaction(async (tx) => {
+		const existingLike = await tx.like.findUnique({
+			where: {
+				userId_miiId: {
+					userId: Number(session.user.id),
+					miiId,
+				},
+			},
+		});
+
+		if (existingLike) {
+			// Delete the like if it exists
+			await tx.like.delete({
+				where: {
+					userId_miiId: {
+						userId: Number(session.user.id),
+						miiId,
+					},
+				},
+			});
+
+			const updatedMii = await tx.mii.update({
+				where: { id: miiId },
+				data: { likes: { decrement: 1 } },
+				select: { likes: true },
+			});
+
+			return { liked: false, count: updatedMii.likes };
+		} else {
+			// Create a new like if it doesn't exist
+			await tx.like.create({
+				data: {
+					userId: Number(session.user.id),
+					miiId,
+				},
+			});
+
+			const updatedMii = await tx.mii.update({
+				where: { id: miiId },
+				data: { likes: { increment: 1 } },
+				select: { likes: true },
+			});
+
+			return { liked: true, count: updatedMii.likes };
+		}
+	});
+
+	return Response.json({ success: true, liked: result.liked, count: result.count });
+}
diff --git a/src/app/components/like-button.tsx b/src/app/components/like-button.tsx
index 09ae5a4..a3d598e 100644
--- a/src/app/components/like-button.tsx
+++ b/src/app/components/like-button.tsx
@@ -6,26 +6,32 @@ import { Icon } from "@iconify/react";
 
 interface Props {
 	likes: number;
+	miiId: number | undefined;
+	isLiked: boolean;
 	isLoggedIn: boolean;
 	big?: boolean;
 }
 
-export default function LikeButton({ likes, isLoggedIn, big }: Props) {
-	const [isLiked, setIsLiked] = useState(false);
+export default function LikeButton({ likes, isLiked, miiId, isLoggedIn, big }: Props) {
+	const [isLikedState, setIsLikedState] = useState(isLiked);
 	const [likesState, setLikesState] = useState(likes);
 
-	const onClick = () => {
+	const onClick = async () => {
 		if (!isLoggedIn) redirect("/login");
 
-		setIsLiked((prev) => !prev);
+		setIsLikedState((prev) => !prev);
 		setLikesState((prev) => (isLiked ? prev - 1 : prev + 1));
 
-		// todo: update database
+		const response = await fetch("/api/like", { method: "PATCH", body: JSON.stringify({ miiId }) });
+		const { liked, count } = await response.json();
+
+		setIsLikedState(liked);
+		setLikesState(count);
 	};
 
 	return (
 		<button onClick={onClick} className={`flex items-center gap-2 text-red-400 cursor-pointer ${big ? "text-3xl" : "text-xl"}`}>
-			<Icon icon={isLiked ? "icon-park-solid:like" : "icon-park-outline:like"} />
+			<Icon icon={isLikedState ? "icon-park-solid:like" : "icon-park-outline:like"} />
 			<span>{likesState}</span>
 		</button>
 	);
diff --git a/src/app/components/mii-list.tsx b/src/app/components/mii-list.tsx
index b8afb20..a89690c 100644
--- a/src/app/components/mii-list.tsx
+++ b/src/app/components/mii-list.tsx
@@ -8,6 +8,7 @@ import Link from "next/link";
 
 interface Props {
 	searchParams: Promise<{ [key: string]: string | string[] | undefined }>;
+	// for use on profiles
 	userId?: number;
 }
 
@@ -38,7 +39,7 @@ export default async function MiiList({ searchParams, userId }: Props) {
 	const whereTags = tagFilter.length > 0 ? { tags: { hasSome: tagFilter } } : undefined;
 
 	// If the mii list is on a user's profile, don't query for the username
-	const include =
+	const userInclude =
 		userId == null
 			? {
 					user: {
@@ -63,9 +64,24 @@ export default async function MiiList({ searchParams, userId }: Props) {
 			userId,
 		},
 		orderBy,
-		include,
+		include: {
+			...userInclude,
+			likedBy: {
+				where: {
+					userId: Number(session?.user.id),
+				},
+				select: {
+					userId: true,
+				},
+			},
+		},
 	});
 
+	const formattedMiis = miis.map((mii) => ({
+		...mii,
+		isLikedByUser: mii.likedBy.length > 0, // True if the user has liked the Mii
+	}));
+
 	return (
 		<div className="w-full">
 			<div className="flex justify-between items-end mb-2">
@@ -99,13 +115,13 @@ export default async function MiiList({ searchParams, userId }: Props) {
 			</div>
 
 			<div className="grid grid-cols-4 gap-4 max-lg:grid-cols-3 max-sm:grid-cols-2 max-[25rem]:grid-cols-1">
-				{miis.map((mii) => (
+				{formattedMiis.map((mii) => (
 					<div
 						key={mii.id}
 						className="flex flex-col bg-zinc-50 rounded-3xl border-2 border-zinc-300 shadow-lg p-3 transition hover:scale-105 hover:bg-cyan-100 hover:border-cyan-600"
 					>
 						<Link href={`/mii/${mii.id}`}>
-							<img src="https://placehold.co/600x400" alt="mii" className="rounded-xl" />
+							<img src="https://placehold.co/600x400" alt="mii" className="rounded-xl border-2 border-zinc-300" />
 						</Link>
 						<div className="p-4 flex flex-col gap-1 h-full">
 							<Link href={`/mii/${mii.id}`} className="font-bold text-2xl overflow-hidden text-ellipsis line-clamp-2" title={mii.name}>
@@ -120,7 +136,7 @@ export default async function MiiList({ searchParams, userId }: Props) {
 							</div>
 
 							<div className="mt-auto grid grid-cols-2 items-center">
-								<LikeButton likes={mii.likes} isLoggedIn={session?.user != null} />
+								<LikeButton likes={mii.likes} miiId={mii.id} isLiked={mii.isLikedByUser} isLoggedIn={session?.user != null} />
 
 								{userId == null && (
 									<Link href={`/profile/${mii.user.id}`} className="text-sm text-right overflow-hidden text-ellipsis">
diff --git a/src/app/mii/[slug]/page.tsx b/src/app/mii/[slug]/page.tsx
index 852e12c..25ad627 100644
--- a/src/app/mii/[slug]/page.tsx
+++ b/src/app/mii/[slug]/page.tsx
@@ -27,9 +27,18 @@ export default async function ProfilePage({ params }: Props) {
 		},
 	});
 
+	const isLiked = await prisma.like.findUnique({
+		where: {
+			userId_miiId: {
+				userId: Number(session?.user.id),
+				miiId: Number(slug),
+			},
+		},
+	});
+
 	return (
 		<div className="flex gap-2 max-sm:flex-col">
-			<img src="https://placehold.co/400x300" alt="mii" className="rounded-xl" />
+			<img src="https://placehold.co/400x300" alt="mii" className="rounded-xl border-2 border-zinc-300 shadow-lg" />
 			<div className="flex flex-col gap-1 p-4">
 				<h1 className="text-5xl font-extrabold break-words">{mii?.name}</h1>
 				<div id="tags" className="flex gap-1 mt-1 *:px-2 *:py-1 *:bg-orange-300 *:rounded-full *:text-xs">
@@ -50,7 +59,7 @@ export default async function ProfilePage({ params }: Props) {
 				</div>
 
 				<div className="mt-auto">
-					<LikeButton likes={mii?.likes ?? 0} isLoggedIn={session?.user != null} big />
+					<LikeButton likes={mii?.likes ?? 0} miiId={mii?.id} isLiked={isLiked != null} isLoggedIn={session?.user != null} big />
 				</div>
 			</div>
 		</div>