Free Developer Tools
Small formatting and inspection tasks interrupt development work. This collection puts the quick checks in one place: inspect a URL, validate structured text, test a pattern, or produce a CSS value. Browser-based tools are useful for local snippets, but review any output before putting it into production code.
Inspect and validate data
JSON Formatter parses and formats JSON, XML Validator checks XML syntax, and Regex Tester shows matches and captured groups against sample text. These tools help catch obvious input mistakes; they do not replace schema validation, automated tests, or safe handling of untrusted patterns.
Convert data for documentation
CSV to Markdown Table handles quoted and multiline CSV cells for a table you can paste into documentation. CSV / JSON Converter changes common data formats, while Number Base Converter handles signed integers in bases 2 through 36 without rounding large values.
Inspect checksums and networks
File Hash Checker calculates a SHA checksum and compares it with an expected value. HMAC Generator authenticates a message with a shared key for debugging API integrations. IPv4 Subnet Calculator shows network and host ranges from a CIDR address. Review the source of any checksum and use test keys in shared examples.
Work with web addresses and text
URL Parser separates an HTTP address into its host, path, fragment, and query values. URL Encoder handles URL components, while HTML Entity Encoder / Decoder handles special characters in HTML text. Base64 is useful for transport and debugging, but it does not encrypt data.
Check visual code
Color Contrast Checker calculates the ratio between two solid colors. CSS Gradient Generator creates a linear-gradient rule, and Color Converter provides RGB and HSL values from a HEX color. Always preview these values in the real page layout.
These utilities run locally in your browser. Do not paste production secrets or private tokens into shared screenshots or copied output.