SimpleToolbox
Developer Tools

Web Developer Utilities

Fast, client-side tools for formatting code, testing regex, and converting data formats.

JSON Formatter

Validate and beautify JSON payloads.

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Base64 Encoder

Encode and decode strings or files to Base64.

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QR Code Gen

Generate customizable SVG/PNG QR codes.

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Regex Tester

Test and debug regular expressions in real-time.

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CSS Minifier

Minify and compile CSS styles.

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LLM API Cost

Estimate token overhead for OpenAI, Claude, and Gemini.

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String Formatter

Instantly convert text to camelCase, snake_case, PascalCase, or kebab-case.

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JSON to CSV

Flatten and convert nested JSON objects into tabular CSV data.

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Meta Tag Gen

Generate HTML meta tags, Twitter Cards, and Open Graph data.

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UUID Generator

Instantly generate bulk v4 UUIDs / GUIDs.

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JWT Decoder

Decode JSON Web Tokens securely without sending payloads.

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HTML Entity Encoder

Safely encode and decode HTML entities to prevent XSS.

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Markdown to HTML

Convert Markdown to clean HTML with live preview and XSS protection.

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Text Diff Checker

Compare two text blocks or code snippets to find the exact differences.

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Unix Timestamp

Convert Unix epoch times to human-readable dates and vice versa.

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IP Subnet Calculator

Calculate network CIDR ranges, broadcast addresses, and usable hosts.

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JSON to YAML

Instantly translate JSON configurations into clean, readable YAML.

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URL Encoder/Decoder

Safely encode URLs for HTTP parameters or decode percent-encoded strings.

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SQL Formatter

Instantly beautify messy SQL queries with perfect indentation.

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Free developer tools for code formatting, encoding, hashing, and network analysis — all browser-based with no account required. Built for the daily workflow of working engineers.

Frequently Asked Questions

What developer tools are available?

JSON formatter, JSON to CSV, JSON to YAML, regex tester, CSS minifier, SQL formatter, string formatter, URL encoder, Base64 encoder, UUID generator, JWT decoder, Markdown to HTML, HTML entity encoder, Unix timestamp converter, bcrypt generator, network subnet calculator, diff checker, LLM API cost estimator, and meta tag generator.

Do these tools work with sensitive code?

Yes — every tool runs client-side in your browser. No code, queries, tokens, or IP addresses are ever sent to a server.

Are there usage limits?

No limits of any kind — no rate limiting, no character caps, no account required.

Can I use these tools offline?

Yes. After the page loads, all processing is local. You can disconnect from the internet and every tool continues to function.