Web + CLI + AI (MCP)
All your mission-critical utilities executed locally in your browser, terminal, and AI agents. Zero server tracking, sub-millisecond transforms, and seamless multi-stage pipelines.
Ctrl + K
npx castov`` castov mcp
Simulates the full castov-cli suite locally via WebCrypto and instant transforms.
Click any quick-run chip above or type help to see commands.
Why Developers Choose Castov #
Five architectural decisions that make Castov the preferred toolkit for modern software teams.
Zero-Data Logging
WebCrypto 100% of cryptography, JWT inspection, JSON formatting, and timestamp parsing executes in local browser memory. Not a single keystroke is sent to external servers.
Tool Pipelines ("Pipe to...")
Chaining Pass outputs seamlessly across utilities in one click: JSON directly to TypeScript interfaces, Cron schedules into world timezones, and diffs to schema generators without clipboard juggling.
Unified Ecosystem
Web • CLI • MCP
The exact same 13 utilities work on the Web, in your local terminal via castov, and inside Cursor or Claude via our Grade-A certified Model Context Protocol server.
Encrypted URL Shares
Zero-Server
Share inputs, diffs, and settings with teammates instantly. Payloads are compressed into the URL hash fragment (#) so servers never see what you shared.
E2EE Cloud Sync & Team Vaults
GitHub OAuth Zero-friction leverage unlocked on registration
Connect your GitHub account to sync pinned utilities, presets, and dev preferences across all your machines. Collaborate with teammates using RSA-OAEP encrypted Team Vaults to share .env files without cleartext exposure in chat channels.
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 --help
Advanced 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 data channels coordinated through public signaling servers (which may receive connection metadata). Workflow graphs, node configurations, and payload data are never stored on Castov servers.
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.
Labs #
Experimental tools Experimental tools: WebRTC P2P mesh, steganography, AST parsing, and in-browser WebGL computing.
Frequently Asked Questions #
Everything you need to know about Castov.
Frequently Asked Questions #
Is Castov really free? #
Is my data sent to a server? #
What is a Unix timestamp? #
Should I use seconds or milliseconds? #
Which time zones are supported? #
Ready to supercharge your workflow? #
Free browser-based developer tools. Some collaboration, cloud, and external API features may require an account or additional configuration.