Developer Tools for Formatting, Encoding and Testing

These are the small utilities that sit between larger pieces of work: checking why an API response will not parse, decoding a token to see what is actually in it, or confirming a regular expression matches what you think it does before it reaches production.

Developer Tools (27)

Base64 Encoder and Decoder

Encode text to Base64 or decode Base64 back to readable text for API payloads, tokens, data URIs, headers, and debugging.
Bcrypt Hash Generator

Generate bcrypt password hashes with selectable cost rounds and verify plain text against an existing bcrypt hash.
Cron Expression Builder

Build 5-field cron expressions for minutes, hours, days, months, and weekdays with quick schedule presets.
CSV to JSON Converter

Convert CSV rows into JSON arrays, or flatten JSON arrays back to CSV for spreadsheets, imports, exports, and API payloads.
cURL Command Builder

Build cURL commands with HTTP method, request URL, headers, query parameters, bearer token, and JSON body for API testing.
Hash Generator

Generate MD5, SHA-1, SHA-256, and SHA-512 hashes from text for checksums, integrity checks, and developer testing.
HTML Entity Encoder & Decoder

Encode <, >, &, quotes, and Unicode characters into HTML entities, or decode entities back into readable text.
HTML Formatter

Format messy HTML with indentation or minify markup by removing extra whitespace before editing templates, emails, or CMS snippets.
JavaScript Keycode Finder

Press any key to inspect JavaScript keyboard event values such as key, code, which, location, and modifier states.
JavaScript Minifier & Formatter

Beautify JavaScript snippets for reading or minify functions, objects, and browser scripts before copying into a page or bundle.
JSON Formatter and Validator

Format, validate, minify, and debug JSON from API responses, config files, webhooks, logs, and copied payloads.
JSON to C# Class Converter

Paste JSON and generate C# POCO classes with typed properties, nested models, arrays, nullable fields, and a custom root class name.
JSON to YAML Converter

Convert JSON objects and arrays into readable YAML for Docker, CI files, Kubernetes snippets, and configuration examples.
JWT Decoder

Decode JWT header and payload JSON to inspect token claims, issuer, subject, audience, and expiry values.
JWT Generator

Create signed JWTs from custom header JSON, payload JSON, secret key, and algorithm settings for testing.
Mock Data Generator

Generate sample records with names, emails, phone numbers, countries, dates, amounts, companies, and IDs in JSON or CSV format.
Regex Tester

Test regular expressions against sample text, inspect matches and groups, switch flags, and debug patterns before using them in code.
SQL Formatter

Format SELECT queries, joins, subqueries, WHERE clauses, aliases, and keyword casing for debugging or code review.
Text Encryptor & Decryptor

Encrypt text with a secret key or decrypt previously encrypted text for private notes, demos, and local experiments.
Unix Timestamp Converter

Convert Unix epoch timestamps in seconds or milliseconds to local and UTC date-time, or convert a date-time back to epoch.
URL Encoder & Decoder

Encode or decode URLs, query parameters, form values, spaces, Unicode text, and reserved characters safely.
URL Parser

Parse a URL into protocol, host, port, path, fragment, and query parameters for debugging links, redirects, tracking, and forms.
User-Agent Parser

Parse a user-agent string to identify browser, rendering engine, operating system, device family, CPU hints, and bot-like signals.
UUID Generator

Generate one or many UUID v4 identifiers with optional hyphens, uppercase formatting, or braces for databases, APIs, and test data.
UUID Validator

Validate UUID strings, detect version and variant, identify nil UUIDs, and review multiple IDs line by line.
XML to JSON Converter

Convert XML documents into JSON or turn JSON objects back into XML for API testing, data cleanup, and migration checks.
YAML to JSON Converter

Convert YAML mappings, lists, and nested config files into JSON for APIs, validators, app settings, and debugging.

Guides for This Topic

Guide · 7 min read
How to Format JSON and Fix Common JSON Errors

Understand JSON formatting, validation errors, missing commas, broken quotes, trailing commas and cleanup before using JSON in APIs or configuration files.
Guide · 7 min read
How to Encode, Decode and Hash Text for Developer Workflows

Understand when to use Base64, URL encoding, HTML entities, and cryptographic hashes for API work, data transfer, authentication systems, and secure credential storage.

Formatting Is How You Find the Error

A minified JSON payload hides its own mistakes. Running it through a formatter both indents the structure and reports exactly where parsing failed, which is usually a trailing comma, an unescaped quote, or a single quote where the specification requires double. Reading the raw string looking for the problem is far slower than letting a parser point at the character.

Encoding Is Not Encryption

Base64 and URL encoding make data safe to transport; they do nothing to protect it. Anyone can decode either in seconds. A JWT is the same story: its payload is Base64 and readable by anyone holding the token. The signature proves the token was not altered, but it does not hide the contents, so nothing secret belongs in a JWT payload.

Hashing Choices Depend on Purpose

For checking that a file downloaded intact, a fast hash like SHA-256 is the right tool. For storing passwords, fast is exactly wrong, because it lets an attacker try billions of guesses. Password storage wants a deliberately slow algorithm such as bcrypt, with a work factor that can be raised as hardware improves. MD5 and SHA-1 should not be used for either job any more.

Test Patterns Against Real Data

A regular expression that works on three hand-written examples will meet inputs you did not imagine: empty strings, unicode, unexpected whitespace, and text far longer than you planned for. Testing against realistic samples before deploying catches the cases that would otherwise surface as production bugs.

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