Privacy & Security
LangStop is designed from the ground up to protect your data. Every tool runs entirely in your browser. We cannot see, store, or access what you process — because it never reaches our servers.
How LangStop Protects Your Data
Static assets loaded from CDN · All processing via WebAssembly + JavaScript · Zero data egress
Architecture Overview
LangStop uses a static-first, client-only architecture. The entire application is pre-built as static HTML, CSS, and JavaScript files served from a global CDN. There are no application servers, no databases, no API endpoints processing your data.
When you use a tool, your browser loads the necessary JavaScript and WebAssembly modules from the CDN, then executes all processing locally. Your input data — whether text pasted into an editor, files selected for upload, or configuration values — is processed entirely within your browser's memory using your device's CPU.
This architecture means LangStop physically cannot access your data. There is no server receiving it, no database storing it, no log recording it. Once you close the browser tab, your data is gone forever.
Data Flow
| What | What Happens | Server? |
|---|---|---|
| Code you paste into tools | Processed locally in your browser via WASM/JavaScript | Never sent |
| Files you upload | Read via FileReader API, processed entirely client-side | Never sent |
| Tool preferences & settings | Stored in browser localStorage / IndexedDB | Never sent |
| Page views (analytics) | Anonymized, privacy-preserving page view counting | Aggregated, no input data |
| Theme preference | Stored in browser localStorage | Never sent |
| Recently used tools | Stored in browser localStorage | Never sent |
How to Verify
You don't have to trust us. You can verify LangStop's privacy claims yourself using your browser's built-in Developer Tools.
Open Developer Tools
Press F12 or Ctrl+Shift+I (Cmd+Option+I on Mac) to open your browser's Developer Tools panel.
Navigate to the Network Tab
Click the 'Network' tab. This shows every network request your browser makes.
Use Any LangStop Tool
Go to any tool page. Paste data, format JSON, validate YAML, decode JWT — use it as you normally would.
Observe Zero Data Requests
Watch the Network tab. You will see zero requests to any server for tool processing. Only the initial page load appears. The rest is entirely local.
Verifying this takes 30 seconds. Zero network requests will appear when using any LangStop tool.
Security Transparency
No Accounts, No Risk
Without user accounts, there are no credentials to leak, no sessions to hijack, and no personal data to expose.
No Tracking Cookies
We use zero tracking cookies. Theme preferences and tool history are stored locally in your browser via localStorage and IndexedDB.
Fully Open Source
Every line of code is publicly auditable. No hidden analytics, no secret data collection, no third-party tracking scripts.
Dependency Transparency
All processing libraries are audited open-source packages: js-yaml, fast-xml-parser, papaparse, smol-toml, jose, jsonrepair, and more.
HTTPS Everywhere
All traffic is encrypted via HTTPS. Static assets served through Vercel's global edge network with A+ SSL rating.
Regular Audits
Dependabot monitors dependencies for vulnerabilities. Community reviews welcome via GitHub pull requests.
Frequently Asked Questions
Do you store my JSON data or any input I paste?
No. Your data never reaches our servers. All processing happens in your browser using WebAssembly and JavaScript. We physically cannot store what we never receive.
Can you see what I paste into LangStop tools?
No. Since every tool runs entirely client-side in your browser, your input is never transmitted over the network (except for loading the initial page assets from our CDN). There are no servers processing, inspecting, or storing your data at any point.
What data does LangStop collect?
We use privacy-preserving, anonymized page view analytics to understand which tools are most popular. This data includes page URLs visited, browser type, and approximate country (from IP). It does NOT include any data you enter into tools, any file contents, any keystrokes, or any personally identifiable information. You can verify this yourself using your browser's Developer Tools.
Is LangStop open source?
Yes. LangStop is fully open source. You can audit every line of code, verify there are no hidden server calls, and even self-host the entire application.
Can I use LangStop without an internet connection?
Yes. Install LangStop as a Progressive Web App (PWA) and all 180+ tools work completely offline. After the initial page load, zero network connectivity is required for any tool functionality.
Does LangStop use cookies?
LangStop does not use any tracking cookies. Your theme preference and recently used tools are stored locally in your browser using localStorage and IndexedDB. No cookie consent banners needed.
Additional Details
Third-Party Services: LangStop is hosted on Vercel's edge network. Static assets (HTML, CSS, JavaScript, WASM binaries) are served from Vercel's CDN. We use Cloudflare for DNS. No third-party services process your tool input data.
Affiliate Links: LangStop participates in the Amazon Associates affiliate program. Clicking product recommendations may send referral data to Amazon. This does not affect tool functionality or data processing.
Contact & Reporting: If you discover a security concern, please open a GitHub issue or contact us directly. We take all reports seriously and will respond promptly.
Last updated: June 2026