Dev & Tech Tools

JSON formatters, regex testers, encoders, decoders, hash generators, and the everyday developer utilities that should just work when you need them.

The JSON formatter, regex tester, and base64 encoder/decoder handle the utility tasks that come up constantly — usually in the middle of something else. They're not hard problems. They just require a tool that loads fast, doesn't obscure the text area with ads, and doesn't ask you to sign up.

Every tool here runs entirely in your browser. Paste a production JWT, a malformed JSON blob, or an API response with PII — nothing touches a server. Privacy isn't a feature you opt into; it's the default architecture.

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Dev & Tech Tools

AI Token Calculator

Count tokens and estimate API costs for any AI model.

Color Converter & Palette Generator

Convert colors between formats and generate harmonious palettes

Cron Expression Builder

Build and decode cron expressions with a visual schedule editor.

CSS Generator

Generate beautiful CSS gradients, shadows, and glassmorphism effects.

Design Token & Color System Generator

Generate complete design systems from a single brand color

DNS Lookup

Query and inspect all DNS records for any domain instantly

Encoding Toolkit

Encode, decode, and convert between Base64, URL, HTML, and more.

Hash Generator

Generate MD5, SHA-1, SHA-256, and SHA-512 hashes instantly

HTML Cleaner & Formatter

Clean messy HTML from Word, Google Docs, and CMS editors

HTTP Security Header Grader

Audit your HTTP security headers with A-F grades per category

IP Subnet Calculator

Calculate subnet details from any IP/CIDR notation

JSON Formatter & Validator

Format, validate, and explore JSON with instant error detection

JWT Decoder

Decode, inspect, and validate JSON Web Tokens instantly.

Link Building Cost Calculator

Estimate link building costs by DA, niche, and link type

Meta Tag Generator

Generate SEO meta tags, Open Graph, and Twitter Cards with live previews

Password Generator

Generate cryptographically secure passwords with strength analysis

QR Code Generator

Generate customizable QR codes for URLs, WiFi, contacts, and more

Regex Tester

Build and test regular expressions with live match highlighting

Robots.txt Generator

Build and validate robots.txt files visually

SQL Formatter

Format and beautify SQL queries instantly

SQL Query Builder & Explainer

Build SQL visually or paste queries for plain-English explanations

UUID Generator

Generate, validate, and format UUIDs instantly

XML Sitemap Generator

Generate valid XML sitemaps with URL validation and smart splitting

Getting More from Dev & Tech Tools

Choosing the right tool for the task

For JSON work, the JSON formatter handles validation, formatting, and minification — paste any JSON blob and it either formats it cleanly or reports exactly where the syntax error is. The regex tester runs against a test string in real time and highlights matches; the flavor defaults to JavaScript regex with a toggle for PCRE-compatible syntax. The encoding toolkit handles base64, URL encoding, HTML entities, and hex in one interface.

The JWT decoder parses the header, payload, and signature without needing a secret — useful for inspecting token claims without validation. The hash generator supports MD5, SHA-1, SHA-256, and SHA-512. For network work, the subnet calculator takes CIDR notation and returns network address, broadcast, host range, and available host count.

What these tools won't tell you

Syntax validation isn't semantic validation — the JSON formatter can confirm your JSON is syntactically valid without knowing whether the structure matches the schema your API expects. The regex tester shows matches against a test string you provide; it can't tell you whether your pattern handles edge cases in real production data.

Hash generation confirms what a hash looks like; it doesn't assess whether MD5 or SHA-1 are appropriate for your use case — they're not, for cryptographic security. Use SHA-256 or stronger. The subnet calculator outputs network addresses and host ranges but doesn't validate routing or firewall configurations.

Why your data never leaves the browser

Every tool in this category runs as client-side JavaScript — the compute happens in your browser, not on a remote server. When you paste a JWT with production claims, a JSON blob with user PII, a database connection string, or any sensitive configuration, it never travels over the network. There's no backend, no logging, no analytics on input content.

This matters for developer tools more than almost any other category: the data being processed is often production data, internal credentials, or sensitive payloads. Client-side execution is the only architecture that makes it unambiguously safe to use these tools at work. Verify it yourself with your browser's network tab.

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Who Are These Tools For?

Software Developers

Format JSON, test regex patterns, encode and decode strings, and run the small utility tasks that come up on any given afternoon.

DevOps & SREs

Decode JWT tokens, inspect API payloads, calculate subnets, and troubleshoot data formats without leaving the browser.

CS Students

Experiment with JSON structure, regex syntax, and encoding schemes with immediate visual feedback — no local environment setup required.

Dev & Tech vs Writing & Content — Code vs Prose

Dev & Tech tools process structured input: JSON objects, base64 strings, regex patterns, JWT tokens, CSS rules. The inputs are data formats — not sentences.

Writing & Content tools process natural language: word counts, readability scores, headline analysis, meta descriptions. Schema markup generation is the clearest overlap — JSON-LD is structured data (Dev & Tech) that describes content written in natural language (Writing & Content). If you're generating the markup, start in Dev & Tech; if you're writing the content it describes, start in Writing & Content. Both categories have a schema tool for their respective starting points.

Frequently Asked Questions

No. Every tool in the Dev & Tech category runs as client-side JavaScript in your browser. Input data — including JWTs, API responses, code snippets, and configuration files — is processed locally and never transmitted. You can verify this yourself with your browser's network tab.

Yes — the client-side architecture means no data leaves your machine. That said, be careful when working with private keys or credentials: even a tool that doesn't transmit data can expose sensitive values on shared screens or in browser history. Treat those with the usual care.

The SQL formatter takes existing SQL and makes it readable — consistent indentation, keyword casing, line breaks. The SQL query builder helps you construct a query from scratch using a guided interface. They solve different problems: one cleans up what you have, the other helps you write something new.

It calculates token counts using the same tokenization logic (tiktoken for GPT-family models, approximate counts for Claude and other models) and converts those counts to estimated cost at current published API pricing. It's useful for estimating inference costs before running a large batch job.

Yes — MD5, SHA-1, SHA-256, and SHA-512 outputs match the standard algorithm specifications. Note that MD5 and SHA-1 are considered cryptographically broken for security purposes — collision attacks exist. For password hashing, use bcrypt, Argon2, or scrypt rather than any of these direct hash functions.

It defaults to JavaScript (ECMA-262) regex, which runs natively in the browser. A PCRE-compatible mode is available for server-side PHP, Python, and Ruby patterns. Full POSIX ERE and BRE support is not included — for that, test locally against your actual runtime.

Key Terms

JSON (JavaScript Object Notation): A lightweight text format for structured data — key-value pairs and ordered lists, human-readable and widely supported across languages. The de facto standard for API responses.
Regex (regular expression): A pattern-matching syntax for finding, extracting, or replacing text. A single regex can match thousands of string variations — the regex tester helps you see exactly which ones, and which ones slip through.
Base64: An encoding scheme that converts binary data into a string of ASCII characters. Used to transmit binary data over text-only channels — common in email attachments, data URIs, and API authentication headers.
JWT (JSON Web Token): A compact, self-contained token format for transmitting claims (user ID, roles, expiry) between parties. Consists of three base64url-encoded sections: header, payload, and signature.
Cryptographic hash: A fixed-length output generated from any input. The same input always produces the same hash; a one-character change produces a completely different output. Used for data integrity checks and — with secure algorithms — password storage.
UUID: Universally Unique Identifier — a 128-bit label formatted as 32 hex characters in five groups. Version 4 UUIDs are randomly generated and have collision probability so low they're treated as globally unique.
CIDR notation: A compact way to express a network address and its subnet mask — e.g., 192.168.1.0/24, where /24 means the first 24 bits are the network prefix, leaving 8 bits (256 addresses) for hosts.