All-in-One Developer Toolbox — Free & Client-Side
ToolboxDevs brings together the most commonly needed utilities for everyday software development,
all in one place and all running entirely in your browser. No sign-up, no installs, no data ever
leaves your machine. Below is a quick guide to each tool and when to use it.
Formatters & Validators
JSON Formatter & Beautifier
JSON (JavaScript Object Notation) is the de-facto standard for web API payloads,
configuration files, and NoSQL documents. Raw API responses are often delivered as a single minified
line. Our JSON formatter adds 2-space indentation and line breaks, turning an unreadable blob into a
clean, structured document — while simultaneously validating syntax and reporting exact error positions.
You can also minify JSON to remove all whitespace for production payloads.
XML Formatter & Beautifier
XML powers configuration files (pom.xml, web.config),
SOAP services, RSS feeds, SVG graphics, and Office document formats. Like JSON, XML is frequently
transmitted in compact form. The XML formatter parses and re-serializes the document with consistent
indentation and attribute alignment, making it easy to read or diff. Minify mode produces a
single-line output for embedding or transmission.
Converters
JSON ↔ C# Class Converter
Paste a JSON object and instantly get a strongly-typed C# class with proper property names and
[JsonPropertyName] attributes — ready to drop into your .NET project. The reverse
direction serializes a C# class back to a sample JSON object, helping you verify your model matches
the expected API contract. No code generation server required; all logic runs in the browser.
Encoders & Decoders
Base64 Encoder / Decoder
Base64 is used to safely embed binary data (images, files, tokens) in text-based formats like JSON,
HTML, or HTTP headers. Paste any UTF-8 text to encode it, or paste a Base64 string to decode it
back. Multi-byte characters (emoji, accented letters, CJK) are handled correctly via
TextEncoder/TextDecoder.
URL Encoder / Decoder
URL-encodes special characters using encodeURIComponent so they are safe to include in
query strings and path segments. Paste a raw URL or query string to encode it, or paste an
already-encoded string to decode it back to readable form. Useful when building REST calls,
debugging redirect chains, or constructing OAuth parameters.
HTML Encoder / Decoder
Converts characters like <, >, &, and
" to their HTML entity equivalents (<,
>, etc.) to prevent XSS vulnerabilities when inserting user content into HTML.
The decoder reverses the process — handy when reading encoded content from a CMS or API response.
Hex Converter (Text ↔ Hex)
Converts plain text to its hexadecimal byte representation and vice versa. Commonly used in
cryptography, network debugging, and low-level protocol work where byte values need to be
inspected or constructed manually.
JWT Decoder
Paste any JSON Web Token to instantly see its header and payload
as formatted JSON — without needing a server or sharing your token with a third-party site. Useful
for debugging authentication issues, checking expiry (exp) or issued-at (iat)
claims, and verifying audience (aud) and issuer (iss) fields. Note: the
signature is not validated; use this tool for inspection only.
Security Generators
Password Generator
Generates cryptographically secure random passwords using crypto.getRandomValues() —
the same API used by password managers. Choose the length (4–128 characters) and which character
sets to include (uppercase, lowercase, digits, special characters). A Fisher-Yates shuffle removes
positional bias so the character-set guarantees do not leak information about the password structure.
UUID / GUID v4 Generator
Generates one or more RFC 4122-compliant version-4 UUIDs (universally unique identifiers) using
crypto.randomUUID(). UUIDs are used as primary keys in distributed databases, correlation
IDs in microservices, idempotency keys in payment APIs, and asset names in cloud storage. Generate
up to 20 at once and copy them all with a single click.
API Key / Token Generator
Produces a cryptographically secure random token of configurable byte length (8–64 bytes) in either
hexadecimal or Base64URL format. Suitable for generating API keys, webhook secrets, CSRF tokens, and
session identifiers that need to be unpredictable and URL-safe.
Hash Generator — SHA-256 & SHA-512
Computes the SHA-256 or SHA-512 digest of any text input using the browser's native
SubtleCrypto API (crypto.subtle.digest). Output is lowercase hexadecimal.
SHA hashes are one-directional — they cannot be reversed — and are used to verify data integrity,
store password digests (with a proper KDF on top), and sign artifacts. SHA-256 produces a 64-character
hex string; SHA-512 produces a 128-character hex string.
.NET Error Guide
A searchable reference of common C#/.NET development errors with step-by-step solutions. Covers
SDK version mismatches, NuGet restore failures (including NU1101 and private feed
authentication), port conflicts on IIS Express and Kestrel, database connection string errors
(LocalDB, SQL Server, Azure SQL, TrustServerCertificate), and IDE environment issues
(OmniSharp/Roslyn cache corruption, locked bin/obj folders). Each entry includes the
exact error message, the most common root cause, and a numbered list of terminal commands to resolve it.
Privacy & Security
Every tool on ToolboxDevs runs entirely inside your web browser using native JavaScript APIs:
JSON.parse, DOMParser, crypto.subtle,
crypto.getRandomValues(), TextEncoder, and TextDecoder.
No data is ever sent to any server. Your code, tokens, passwords, and text stay
completely private. The tools also work offline once the page has been loaded.