Free Developer Tools:
Time, JSON, Encoding & More
Most tools run entirely in your browser.
A complete ecosystem, not just a website.
Castov integrates directly into your workflow. From the browser to the terminal, and right inside your IDE.
Global Command Center
Press Cmd+K anywhere. Inline-compute UUIDs, format dates, and navigate instantly without leaving your keyboard.
MCP Server & CLI
npm v1.4.0Connect 10 Glama Grade-A certified local tools to Claude, Cursor, and Windsurf (npx castov mcp) or run utilities in terminal.
VS Code Extension
OfficialNever context-switch again. Highlight text in your editor to instantly decode Base64, parse JWTs, inspect timestamps, or generate UUIDs.
Deploy Castov Everywhere You Build
Whether inside your local terminal, Docker containers, AI editors, or automated CI/CD pipelines — Castov provides the instant execution layer for developers and MCP AI agents.
Docker Hub
Run Castov CLI and MCP runtime in an isolated, non-root Alpine container with zero host dependencies.
docker run --rm -it castovdev/castov:latest --helpAdvanced Capabilities
We didn't just build formatters. We built the architecture required by modern engineering teams.
P2P Multiplayer Canvas
A visual node-editor for building data pipelines. Connects peers in real-time using WebRTC and CRDTs (Yjs) with direct peer-to-peer sync and zero server storage.
Steganography Environment Vaults
End-to-end encrypted environment variables. We hide your secure AES keys inside standard image pixels (Steganography) for invisible sharing, entirely in your browser.
Test your frontend without a backend. Our Local API Mocker runs entirely in your browser's Service Worker to simulate payloads globally.
Explore Our Toolkit
From time manipulation to cryptography, everything is beautifully structured and instantly accessible.
Timestamp
7 tools
Convert, validate, compare and work with Unix timestamps.
Date & Duration
5 tools
Calculate differences, durations, and add or subtract time from a date.
Time Zones
6 tools
Convert, compare and browse time across the world's time zones.
Developer
33 tools
ISO 8601, RFC 3339, cron and other formats developers work with daily.
- JSON to TypeScript
- Diff Checker
- JSON Formatter & Validator
- Base64 Encode / Decode
- JWT Decoder
- UUID Generator
- Hash Generator
- Gigantic JSON Viewer
- ISO 8601 to Unix
- Unix to ISO 8601
- Unix Timestamp Validator
- Unix Timestamp Batch Converter
- Date Format Converter
- ISO 8601 Converter
- RFC 3339 Converter
- Cron Expression Generator
- Universal Config Sync
- Zero-Knowledge .env Vault
- Universal Secret Scanner
- Shadow API Load Tester
- Docker Architecture Visualizer
- In-Browser SQLite Fiddle
- Code to Image Generator
- CSS Glassmorphism Generator
- GitHub README Builder
- App & Screenshot Mockup Studio
- Favicon & App Icon Generator
- Color Code Converter & Palette Studio
- LLM Token & Cost Visualizer
- Git Disaster Recovery & Time-Traveler
- SVG Keyframe Animator & Studio
- Synthetic Mock Data Studio
- CyberChef & Magic Decoder
Labs
Experimental toolsExperimental tools: WebRTC P2P mesh, steganography, AST parsing, and in-browser WebGL computing.
Generate local fetch interceptor scripts to mock API endpoints.
Share localhost via direct P2P WebRTC connection.
Hide encrypted .env files inside PNG image pixels.
Explore massive JSON architectures in a 3D WebGL universe.
Evolve perfect Regex using local genetic algorithms.
Replay past API states using a visual timeline scrubber.
Semantically merge Git conflicts using AST logic parsing.
Decentralized WebGPU Supercomputer running local AI workloads.
Air-gapped ultrasonic acoustic data transfer protocol.
Browser-native quantum circuit execution via matrix tensors.
Frequently Asked Questions
Everything you need to know about Castov.