Free Developer Utilities Online

Private, rapid, and lightweight browser-based developer tools. Every utility runs completely client-side. Your keys, configuration files, Base64 strings, and raw database parameters never touch any external server.

JSON Formatter

Pretty print, minify, validate, and convert JSON data with syntax highlight.

Base64 Codec

Encode text strings, payloads, or file assets to Base64, or decode them instantly.

UUID v4 Generator

Generate RFC 4122 compliant random UUID v4 identifiers in bulk with custom spacing.

Hash Generator

Calculate cryptographically secure MD5, SHA-1, SHA-256, and SHA-512 checksums.

cURL Converter

Transform standard terminal cURL commands into clean JavaScript, Python, or Go code.

HTML/CSS Minifier

Scrub whitespace, comments, and empty selectors to compress stylesheets and pages.

ER Diagram Creator

Sketch structural database entities, relations, and primary keys using local visual canvas.

Agentic Rules

Draft high-quality markdown files defining constraints and directives for coding assistants.

Secure Browser-Based Engineering Tools

As modern engineering workflows adopt cloud-hosted APIs and browser playgrounds, it has become alarmingly easy to leak secrets, API keys, database hashes, or user tokens into logs. ToolShelf shields your operations by keeping 100% of the computations isolated locally.

Why Client-Side Dev Utilities Excel:

No Telemetry Logging: We do not log inputs, hashes, or credentials. Everything remains in your browser's private state.
Zero Dependencies on External Networks: Load the toolbox once, and format JSON, decode Base64, or generate UUID tokens completely offline at your remote site.
Instant Latency-Free Execution: Because there are no backend API gateways or container wakeups, operations process instantly.