Let's look at the core code mechanics required to build your portfolio's crown jewel: a serverless file transfer platform. Step 1: Chunking the File Natively
While the 60 projects give you a strong baseline, the real power of these technologies shines when you apply them to solve practical problems. One of the most valuable modern applications is —enabling you to send gigabytes of data directly from one device to another without paying for cloud storage, without worrying about privacy violations, and without requiring recipients to install any software.
Now open your editor, pick the first project, and start building. Happy coding! Let's look at the core code mechanics required
For transferring large files securely without cost, several platforms are highly recommended in 2026 based on their free tier limits and security features.
Connect to real-time WebSockets to stream market pricing seamlessly. Now open your editor, pick the first project,
let chunks = []; let totalChunks = 0; receiveChannel.onmessage = async (event) => const packet = JSON.parse(event.data); totalChunks = packet.total; const decrypted = await crypto.subtle.decrypt( name: 'AES-GCM', iv: packet.iv , key, packet.data); chunks.push(decrypted); if (chunks.length === totalChunks) const blob = new Blob(chunks); const url = URL.createObjectURL(blob); const a = document.createElement('a'); a.href = url; a.download = 'received_file'; a.click();
By building in your portfolio, you learn how to bypass the server entirely. You can use vanilla JavaScript to build a web application that facilitates secure, peer-to-peer (P2P), free, large file transfers directly between browsers. Connect to real-time WebSockets to stream market pricing
Implement native HTML5 Drag and Drop events to move items between columns.
document.addEventListener('DOMContentLoaded', () => const dropZone = document.getElementById('drop-zone'); const fileInput = document.getElementById('file-input'); const fileDetails = document.getElementById('file-details'); const fileNameDisplay = document.getElementById('file-name'); const fileSizeDisplay = document.getElementById('file-size'); const progressFill = document.getElementById('progress-fill'); const progressPercent = document.getElementById('progress-percent'); const transferStatus = document.getElementById('transfer-status'); const startBtn = document.getElementById('start-btn'); let selectedFile = null; const CHUNK_SIZE = 1024 * 1024 * 2; // 2MB Processing Chunks // Drag and Drop Event Listeners ['dragenter', 'dragover'].forEach(eventName => dropZone.addEventListener(eventName, (e) => e.preventDefault(); dropZone.classList.add('drag-over'); , false); ); ['dragleave', 'drop'].forEach(eventName => dropZone.addEventListener(eventName, (e) => e.preventDefault(); dropZone.classList.remove('drag-over'); , false); ); dropZone.addEventListener('drop', (e) => const dt = e.dataTransfer; const files = dt.files; if (files.length) handleFileSelection(files[0]); ); fileInput.addEventListener('change', (e) => if (e.target.files.length) handleFileSelection(e.target.files[0]); ); dropZone.addEventListener('click', () => fileInput.click()); function handleFileSelection(file) selectedFile = file; fileNameDisplay.textContent = file.name; fileSizeDisplay.textContent = formatBytes(file.size); fileDetails.classList.remove('hidden'); startBtn.disabled = false; updateProgress(0); transferStatus.textContent = "Ready to secure and transfer"; function formatBytes(bytes) if (bytes === 0) return '0 Bytes'; const k = 1024; const sizes = ['Bytes', 'KB', 'MB', 'GB']; const i = Math.floor(Math.log(bytes) / Math.log(k)); return parseFloat((bytes / Math.pow(k, i)).toFixed(2)) + ' ' + sizes[i]; function updateProgress(percentage) progressFill.style.width = `$percentage%`; progressPercent.textContent = `$Math.round(percentage)%`; // Cryptographic Key Generation & Encryption Streaming async function processAndEncryptFile() startBtn.disabled = true; transferStatus.textContent = "Generating local cryptographic keys..."; try // Generate a secure, single-use symmetric AES-GCM encryption key const key = await window.crypto.subtle.generateKey( name: "AES-GCM", length: 256 , true, ["encrypt", "decrypt"] ); let offset = 0; const fileSize = selectedFile.size; transferStatus.textContent = "Encrypting file payloads locally..."; while (offset < fileSize) const chunk = selectedFile.slice(offset, offset + CHUNK_SIZE); const arrayBuffer = await readChunkAsArrayBuffer(chunk); // Initialization Vector (IV) must be unique for every chunk const iv = window.crypto.getRandomValues(new Uint8Array(12)); const encryptedChunk = await window.crypto.subtle.encrypt( name: "AES-GCM", iv: iv , key, arrayBuffer ); offset += CHUNK_SIZE; const percentComplete = Math.min((offset / fileSize) * 100, 100); updateProgress(percentComplete); // In a production app, append 'encryptedChunk' to WebRTC data channel or stream payload to a target bucket. transferStatus.textContent = "Secure transfer complete!"; transferStatus.style.color = "var(--success)"; catch (error) console.error(error); transferStatus.textContent = "Error safeguarding data stream."; function readChunkAsArrayBuffer(fileChunk) return new Promise((resolve, reject) => const reader = new FileReader(); reader.onload = () => resolve(reader.result); reader.onerror = () => reject(reader.error); reader.readAsArrayBuffer(fileChunk); ); startBtn.addEventListener('click', processAndEncryptFile); ); Use code with caution. Verification and Edge Case Handling
We keep it clean and semantic. We need a drop zone, a status bar, and a password input.
You learn how the browser actually handles binary data (Blobs and ArrayBuffers). 💡 Pro-Tip for "Large Files"