Every day, millions of job applicants, students, visa applicants, and home buyers are forced to upload highly sensitive identity documents—including passport photos, government IDs, bank statements, tax documents, and scanned signatures—to online converters and compressors. 100kb.in was engineered to eliminate this risk entirely by leveraging client-side WebAssembly sandboxes.
The Identity Privacy Crisis in Online Document Processing
What most users do not realize is that traditional online document tools operate on a server-side architecture. When you drag a file into a traditional web converter, your unencrypted file is transmitted over HTTP to a remote cloud server. The server writes your private document to temporary disk storage, processes it, and retains copies until cron jobs run. This legacy model introduces massive security risks: data breaches, server log eavesdropping, unauthorized data scraping for AI training sets, and identity theft.
What is WebAssembly (Wasm)?
WebAssembly is a high-performance binary instruction format designed as a portable compilation target for programming languages like C, C++, Rust, and AssemblyScript. It allows web applications to run low-level algorithms inside web browsers at near-native execution speed.
- Near-Native CPU/GPU Performance: Wasm executes C/C++ algorithms (such as JPEG quantization matrices, PDF stream deflation, and neural network tensor operations) up to 20x faster than traditional JavaScript.
- Hardware-Enforced Memory Isolation: WebAssembly modules run within a tightly sandboxed linear memory space. The browser kernel strictly isolates Wasm memory from external network interfaces.
- Zero Server Infrastructure Footprint: Because all computations execute on your CPU and GPU, zero byte of document payload is ever transmitted over the network.
How 100kb.in Implements Zero-Server Processing
1. Local Blob Ingestion
When you select or drop a file into our upload area, the browser reads the file as a local Blob or ArrayBuffer using the HTML5 FileReader API. The file remains locked within your local device memory.
2. Browser Sandbox Compilation
The input bytes are passed directly into compiled WebAssembly modules: PDF stream deflation via pdf-lib Wasm, image quantization via libjpeg-turbo Wasm, and background removal via ONNX Runtime Web using WebGPU acceleration.
3. Iterative Mathematical Scaling
Instead of trial-and-error uploading, our algorithms execute iterative binary searches locally. If a target size of 50KB is requested, the client-side loop dynamically adjusts quality scaling factors in steps of <5ms until the generated Blob strictly satisfies bytes <= 51200.
4. Local Object URL Generation & Memory Sweep
Once processing is complete, the app creates a temporary local blob: URL. When you click Download, your browser saves the file directly from local RAM to your disk. The moment you close or refresh the tab, browser Garbage Collection sweeps the memory buffers clean.
Security Audit & Verification: Prove It Yourself
- Open Google Chrome, Mozilla Firefox, or Apple Safari.
- Press F12 to open Developer Tools.
- Switch to the Network tab.
- Drag a sensitive document into 100kb.in and hit Compress or Process.
- Observe the Network log: Zero HTTP POST or upload requests are emitted. The network panel remains completely silent because no data leaves your machine!