Git City — 3D GitHub Profile Visualization

Skill by ara.so — Daily 2026 Skills collection.

Git City transforms GitHub profiles into a 3D pixel art city. Each user becomes a unique building: height from contributions, width from repos, window brightness from stars. Built with Next.js 16 (App Router), React Three Fiber, and Supabase.

Quick Setup

git clone https://github.com/srizzon/git-city.git
cd git-city
npm install

# Copy env template
cp .env.example .env.local   # Linux/macOS
copy .env.example .env.local  # Windows CMD
Copy-Item .env.example .env.local  # PowerShell

npm run dev
# → http://localhost:3001

Environment Variables

Fill in .env.local after copying:

# Supabase — Project Settings → API
NEXT_PUBLIC_SUPABASE_URL=https://your-project.supabase.co
NEXT_PUBLIC_SUPABASE_ANON_KEY=your-anon-key
SUPABASE_SERVICE_ROLE_KEY=your-service-role-key

# GitHub — Settings → Developer settings → Personal access tokens
GITHUB_TOKEN=github_pat_your_token_here

# Optional: comma-separated GitHub logins for /admin/ads access
ADMIN_GITHUB_LOGINS=your_github_login

Finding Supabase values: Dashboard → Project Settings → API
Finding GitHub token: github.com → Settings → Developer settings → Personal access tokens (fine-grained recommended)

Project Structure

git-city/
├── app/                    # Next.js App Router pages
│   ├── page.tsx            # Main city view
│   ├── [username]/         # User profile pages
│   ├── compare/            # Side-by-side compare mode
│   └── admin/              # Admin panel
├── components/
│   ├── city/               # 3D city scene components
│   │   ├── Building.tsx    # Individual building mesh
│   │   ├── CityScene.tsx   # Main R3F canvas/scene
│   │   └── LODManager.tsx  # Level-of-detail system
│   ├── ui/                 # 2D overlay UI components
│   └── profile/            # Profile page components
├── lib/
│   ├── github.ts           # GitHub API helpers
│   ├── supabase/           # Supabase client + server utils
│   ├── buildings.ts        # Building metric calculations
│   └── achievements.ts     # Achievement logic
├── hooks/                  # Custom React hooks
├── types/                  # TypeScript type definitions
└── public/                 # Static assets

Core Concepts

Building Metrics Mapping

Buildings are generated from GitHub profile data:

// lib/buildings.ts pattern
interface BuildingMetrics {
  height: number;      // Based on total contributions
  width: number;       // Based on public repo count
  windowBrightness: number;  // Based on total stars received
  windowPattern: number[];   // Based on recent activity pattern
}

function calculateBuildingMetrics(profile: GitHubProfile): BuildingMetrics {
  const height = Math.log10(profile.totalContributions + 1) * 10;
  const width = Math.min(Math.ceil(profile.publicRepos / 10), 8);
  const windowBrightness = Math.min(profile.totalStars / 1000, 1);
  
  return { height, width, windowBrightness, windowPattern: [] };
}

3D Building Component (React Three Fiber)

// components/city/Building.tsx pattern
import { useRef } from 'react';
import { useFrame } from '@react-three/fiber';
import * as THREE from 'three';

interface BuildingProps {
  position: [number, number, number];
  metrics: BuildingMetrics;
  username: string;
  isSelected?: boolean;
  onClick?: () => void;
}

export function Building({ position, metrics, username, isSelected, onClick }: BuildingProps) {
  const meshRef = useRef<THREE.Mesh>(null);
  
  // Animate selected building
  useFrame((state) => {
    if (meshRef.current && isSelected) {
      meshRef.current.rotation.y = Math.sin(state.clock.elapsedTime) * 0.05;
    }
  });

  return (
    <group position={position} onClick={onClick}>
      {/* Main building body */}
      <mesh ref={meshRef}>
        <boxGeometry args={[metrics.width, metrics.height, metrics.width]} />
        <meshStandardMaterial color="#1a1a2e" />
      </mesh>
      
      {/* Windows as instanced meshes for performance */}
      <WindowInstances metrics={metrics} />
    </group>
  );
}

Instanced Meshes for Performance

Git City uses instanced rendering for windows — critical for a city with many buildings:

// components/city/WindowInstances.tsx pattern
import { useRef, useEffect } from 'react';
import { InstancedMesh, Matrix4, Color } from 'three';

export function WindowInstances({ metrics }: { metrics: BuildingMetrics }) {
  const meshRef = useRef<InstancedMesh>(null);
  
  useEffect(() => {
    if (!meshRef.current) return;
    
    const matrix = new Matrix4();
    const color = new Color();
    let index = 0;
    
    // Calculate window positions based on building dimensions
    for (let floor = 0; floor < metrics.height; floor++) {
      for (let col = 0; col < metrics.width; col++) {
        const isLit = metrics.windowPattern[index] > 0.5;
        
        matrix.setPosition(col * 1.1 - metrics.width / 2, floor * 1.2, 0.51);
        meshRef.current.setMatrixAt(index, matrix);
        meshRef.current.setColorAt(
          index,
          color.set(isLit ? '#FFD700' : '#1a1a2e')
        );
        index++;
      }
    }
    
    meshRef.current.instanceMatrix.needsUpdate = true;
    if (meshRef.current.instanceColor) {
      meshRef.current.instanceColor.needsUpdate = true;
    }
  }, [metrics]);

  const windowCount = Math.floor(metrics.height) * metrics.width;
  
  return (
    <instancedMesh ref={meshRef} args={[undefined, undefined, windowCount]}>
      <planeGeometry args={[0.4, 0.5]} />
      <meshBasicMaterial />
    </instancedMesh>
  );
}

GitHub API Integration

// lib/github.ts pattern
import { Octokit } from '@octokit/rest';

const octokit = new Octokit({ auth: process.env.GITHUB_TOKEN });

export async function fetchGitHubProfile(username: string) {
  const [userResponse, reposResponse] = await Promise.all([
    octokit.users.getByUsername({ username }),
    octokit.repos.listForUser({ username, per_page: 100, sort: 'updated' }),
  ]);

  const totalStars = reposResponse.data.reduce(
    (sum, repo) => sum + (repo.stargazers_count ?? 0),
    0
  );

  return {
    username: userResponse.data.login,
    avatarUrl: userResponse.data.avatar_url,
    publicRepos: userResponse.data.public_repos,
    followers: userResponse.data.followers,
    totalStars,
  };
}

export async function fetchContributionData(username: string): Promise<number> {
  // Use GitHub GraphQL for contribution calendar data
  const query = `
    query($username: String!) {
      user(login: $username) {
        contributionsCollection {
          contributionCalendar {
            totalContributions
            weeks {
              contributionDays {
                contributionCount
                date
              }
            }
          }
        }
      }
    }
  `;
  
  const response = await fetch('https://api.github.com/graphql', {
    method: 'POST',
    headers: {
      Authorization: `Bearer ${process.env.GITHUB_TOKEN}`,
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({ query, variables: { username } }),
  });
  
  const data = await response.json();
  return data.data.user.contributionsCollection.contributionCalendar.totalContributions;
}

Supabase Integration

// lib/supabase/server.ts pattern — server-side client
import { createServerClient } from '@supabase/ssr';
import { cookies } from 'next/headers';

export function createClient() {
  const cookieStore = cookies();
  return createServerClient(
    process.env.NEXT_PUBLIC_SUPABASE_URL!,
    process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY!,
    {
      cookies: {
        getAll: () => cookieStore.getAll(),
        setAll: (cookiesToSet) => {
          cookiesToSet.forEach(({ name, value, options }) =>
            cookieStore.set(name, value, options)
          );
        },
      },
    }
  );
}

// lib/supabase/client.ts — browser client
import { createBrowserClient } from '@supabase/ssr';

export function createClient() {
  return createBrowserClient(
    process.env.NEXT_PUBLIC_SUPABASE_URL!,
    process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY!
  );
}

Achievement System

// lib/achievements.ts pattern
export interface Achievement {
  id: string;
  name: string;
  description: string;
  icon: string;
  condition: (stats: UserStats) => boolean;
}

export const ACHIEVEMENTS: Achievement[] = [
  {
    id: 'first-commit',
    name: 'First Commit',
    description: 'Made your first contribution',
    icon: '🌱',
    condition: (stats) => stats.totalContributions >= 1,
  },
  {
    id: 'thousand-commits',
    name: 'Commit Crusher',
    description: '1,000+ total contributions',
    icon: '⚡',
    condition: (stats) => stats.totalContributions >= 1000,
  },
  {
    id: 'star-collector',
    name: 'Star Collector',
    description: 'Earned 100+ stars across repos',
    icon: '⭐',
    condition: (stats) => stats.totalStars >= 100,
  },
  {
    id: 'open-sourcer',
    name: 'Open Sourcer',
    description: '20+ public repositories',
    icon: '📦',
    condition: (stats) => stats.publicRepos >= 20,
  },
];

export function calculateAchievements(stats: UserStats): Achievement[] {
  return ACHIEVEMENTS.filter((achievement) => achievement.condition(stats));
}

Adding a New Building Decoration

// types/decorations.ts
export type DecorationSlot = 'crown' | 'aura' | 'roof' | 'face';

export interface Decoration {
  id: string;
  slot: DecorationSlot;
  name: string;
  price: number;
  component: React.ComponentType<DecorationProps>;
}

// components/city/decorations/Crown.tsx
export function CrownDecoration({ position, buildingWidth }: DecorationProps) {
  return (
    <group position={[position[0], position[1], position[2]]}>
      <mesh>
        <coneGeometry args={[buildingWidth / 3, 2, 4]} />
        <meshStandardMaterial color="#FFD700" metalness={0.8} roughness={0.2} />
      </mesh>
    </group>
  );
}

// Register in decoration registry
export const DECORATIONS: Decoration[] = [
  {
    id: 'golden-crown',
    slot: 'crown',
    name: 'Golden Crown',
    price: 500,
    component: CrownDecoration,
  },
];

Camera / Flight Controls

// components/city/CameraController.tsx pattern
import { useThree, useFrame } from '@react-three/fiber';
import { useRef } from 'react';
import * as THREE from 'three';

export function CameraController() {
  const { camera } = useThree();
  const targetRef = useRef(new THREE.Vector3());
  const velocityRef = useRef(new THREE.Vector3());

  useFrame((_, delta) => {
    // Smooth lerp camera toward target
    camera.position.lerp(targetRef.current, delta * 2);
  });

  // Expose flyTo function via context or ref
  const flyTo = (position: THREE.Vector3) => {
    targetRef.current.copy(position).add(new THREE.Vector3(0, 10, 20));
  };

  return null;
}

Server Actions (Next.js App Router)

// app/actions/kudos.ts
'use server';

import { createClient } from '@/lib/supabase/server';
import { revalidatePath } from 'next/cache';

export async function sendKudos(toUsername: string) {
  const supabase = createClient();
  const { data: { user } } = await supabase.auth.getUser();
  
  if (!user) throw new Error('Must be logged in to send kudos');

  const { error } = await supabase.from('kudos').insert({
    from_user_id: user.id,
    to_username: toUsername,
    created_at: new Date().toISOString(),
  });

  if (error) throw error;
  
  revalidatePath(`/${toUsername}`);
}

Profile Page Route

// app/[username]/page.tsx pattern
import { fetchGitHubProfile } from '@/lib/github';
import { createClient } from '@/lib/supabase/server';
import { calculateAchievements } from '@/lib/achievements';
import { BuildingPreview } from '@/components/profile/BuildingPreview';

interface Props {
  params: { username: string };
}

export default async function ProfilePage({ params }: Props) {
  const { username } = params;
  
  const [githubProfile, supabase] = await Promise.all([
    fetchGitHubProfile(username),
    createClient(),
  ]);

  const { data: cityProfile } = await supabase
    .from('profiles')
    .select('*, decorations(*)')
    .eq('username', username)
    .single();

  const achievements = calculateAchievements({
    totalContributions: githubProfile.totalContributions,
    totalStars: githubProfile.totalStars,
    publicRepos: githubProfile.publicRepos,
  });

  return (
    <main>
      <BuildingPreview profile={githubProfile} cityProfile={cityProfile} />
      <AchievementGrid achievements={achievements} />
    </main>
  );
}

export async function generateMetadata({ params }: Props) {
  return {
    title: `${params.username} — Git City`,
    description: `View ${params.username}'s building in Git City`,
    openGraph: {
      images: [`/api/og/${params.username}`],
    },
  };
}

Common Development Patterns

LOD (Level of Detail) System

// Simplified LOD pattern used in the city
import { useThree } from '@react-three/fiber';

export function useLOD(buildingPosition: THREE.Vector3) {
  const { camera } = useThree();
  const distance = camera.position.distanceTo(buildingPosition);
  
  if (distance < 50) return 'high';    // Full detail + animated windows
  if (distance < 150) return 'medium'; // Simplified windows
  return 'low';                        // Box only
}

Fetching with SWR in City View

import useSWR from 'swr';

const fetcher = (url: string) => fetch(url).then(r => r.json());

export function useCityBuildings() {
  const { data, error, isLoading } = useSWR('/api/buildings', fetcher, {
    refreshInterval: 30000, // refresh every 30s for live activity feed
  });
  
  return { buildings: data, error, isLoading };
}

Key API Routes

Route	Purpose
GET /api/buildings	Fetch all city buildings with positions
GET /api/profile/[username]	GitHub + city profile data
POST /api/kudos	Send kudos to a user
GET /api/og/[username]	Generate OG share card image
POST /api/webhook/stripe	Stripe payment webhook
GET /admin/ads	Admin panel (requires ADMIN_GITHUB_LOGINS)

Troubleshooting

3D scene not rendering
Check that @react-three/fiber and three versions are compatible. The canvas needs a height set on its container div.

GitHub API rate limits
Use a fine-grained token with appropriate scopes. The app caches GitHub responses in Supabase to avoid repeated API calls.

Supabase auth not working locally
Configure the GitHub OAuth provider in your Supabase project and ensure your local callback URL (http://localhost:3001/auth/callback) is allowlisted.

Buildings not appearing
Check that Supabase Row Level Security policies allow reads on the profiles and buildings tables for anonymous users.

Window shimmer/flicker
This is usually a Z-fighting issue. Add a tiny offset (0.001) to window mesh positions along the normal axis.

Performance issues with many buildings
Ensure instanced meshes are used for windows and the LOD system is active. Avoid creating new THREE.Material instances inside render loops — define them outside components or use useMemo.

Stack Reference

Layer	Technology
Framework	Next.js 16 (App Router, Turbopack)
3D Rendering	Three.js + @react-three/fiber + drei
Database	Supabase (PostgreSQL + RLS)
Auth	Supabase GitHub OAuth
Payments	Stripe
Styling	Tailwind CSS v4 + Silkscreen font
Hosting	Vercel
License	AGPL-3.0