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Use developer tools for fast technical checks without opening a heavyweight app. The goal is simple: make encoding, formatting, subnetting, passwords, URLs, and debugging helpers easy to run in the browser with clear privacy notes.

Fast technical checks in the browser

Developer tools should be copy-friendly, private by default, and clear about security assumptions. They are useful for routine checks, not a substitute for production review.

I need network rangesCalculate CIDR ranges, usable hosts, masks, broadcast addresses, and network blocks.I need a passwordGenerate strong random passwords and review length, symbols, and storage advice.I need URL encodingPercent-encode or decode URL component text without sending it away.I need readable JSONFormat, validate, and copy JSON while keeping the source text in the browser.I need campaign URLsBuild UTM links with clear source, medium, campaign, term, and content fields.
17

tools available

17

guides available

Free

No signup needed

Developer checks to open first

These utilities cover common interface and documentation jobs, including color contrast and Markdown table formatting.

Useful shortcuts

Color Contrast CheckerCheck text, background, focus, disabled, and selected-state contrast before publishing UI.Markdown Table GeneratorCreate GitHub-flavored Markdown tables from headers, rows, and alignment choices.

What this category helps with

  • Technical browser utilities for subnetting, passwords, encoding-style tasks, and developer checks.
  • Local-first tools that avoid sending sensitive technical inputs to a server.
  • Research-backed notes for standards-sensitive workflows such as CIDR and password generation.

Start with these tools

Subnet CalculatorCalculate IPv4 CIDR network, broadcast, mask, wildcard, and usable host range.Password GeneratorGenerate strong random passwords with length, character sets, and ambiguity controls.Base64 Encode / DecodeEncode UTF-8 text to Base64 or decode Base64 back to text.URL Encode / DecodePercent-encode URL component text or decode percent-encoded text.Bandwidth CalculatorEstimate file transfer time from data size and network bandwidth.JSON FormatterFormat and validate JSON with two-space indentation and optional sorted object keys.

All developer utilities

Open a tool, try the examples, then use the matching guide when you need more explanation.

Subnet CalculatorCalculate IPv4 CIDR network, broadcast, mask, wildcard, and usable host range.
Password GeneratorGenerate strong random passwords with length, character sets, and ambiguity controls.
JSON FormatterFormat and validate JSON with two-space indentation and optional sorted object keys.
JSON to CSV ConverterConvert JSON objects or arrays to CSV with nested fields, a table preview, and spreadsheet-safe output.
UUID GeneratorGenerate UUID v4 identifiers with quantity, uppercase, and hyphen options.
Hash GeneratorGenerate SHA-256, SHA-384, or SHA-512 text digests in hexadecimal format.
UTM BuilderBuild campaign URLs with source, medium, campaign, content, and term parameters.
Query String ParserParse URL query strings into JSON or build encoded query strings from key-value lines.
CSS Clamp CalculatorGenerate CSS clamp formulas for fluid font sizes, spacing, and responsive layout values.
API Pricing CalculatorEstimate API usage cost from request count, units per request, unit price, fees, and overhead.

Guides for this category

Each guide uses its matching tool, with example numbers and plain limits.