LangStop

Your Online Developer Toolbox

Format, test, and convert — JSON, APIs, JWTs, ERDs, and more. All your essential dev tools, right in the browser.

🚀
Instant Load
Milliseconds load times mean zero waiting.
🔒
Privacy-first
100% client-side—no data leaves your browser.
⚙️
Developer Focused
Keyboard shortcuts & powerful features.

Featured Tools

ERD Generator

ERD Generator

Generate Entity Relationship Diagrams instantly from your database schema or definitions.

Try ERD Generator
AI Prompt Generator

AI Prompt Generator

Quickly craft, refine, and organize AI prompts with our powerful prompt builder. Save time and boost creativity.

Try AI Prompt Generator
REST API Client

REST API Client

Test, debug, and visualize REST APIs effortlessly with our modern API client. Supports authentication, headers, and response formatting — all in one intuitive interface.

Try REST API Client
Regex Tester

Regex Tester

Test and validate regular expressions instantly. Perfect for developers experimenting with patterns or debugging complex regexes.

Try Regex Tester

How It Works

🔍
Discover Tools
Use the command paletteCtrl+Kor browse the menu to find the right tool.
📥
Input Data
Paste, import a file, or fetch from a URL—data loads instantly in your browser.
🚀
Process & Export
Transform, validate, or convert, then copy or download with a single click.

From the Blog

Developer Toolkit
2025-07-10Blog
Supercharge your workflow with browser-based tools that just work.
Read more →
What is JSON?
2025-07-11Blog
Learn what JSON is, how it replaced XML, where it's used today, and essential tips to master it.
Read more →
What is XML?
2025-07-15Blog
Discover what XML is, its history, how it compares with JSON, key use cases, and best practices to master structured data exchange.
Read more →
What is YAML?
2025-06-18Blog
Learn what YAML is, its syntax, why it’s favored for configuration and data serialization, and best practices to master it.
Read more →
What is Base64?
2025-07-17Blog
Learn what Base64 encoding is, how it works, its common use cases, and best practices for embedding binary data in text formats.
Read more →
What is JWT Encoding?
2025-07-18Blog
Understand how JWT (JSON Web Token) encoding works, its structure, use in authentication and secure data exchange, and best practices for implementation.
Read more →

Frequently Asked Questions

How do I search for a tool?
Press Ctrl+K (or ⌘+K on Mac) to open the command palette.
Is my data private?
All processing is client-side; we never store data.
Can I use these tools offline?
Yes, once loaded, everything works offline.

Ready to streamline your development?

Get Started Now