Data Validators

The Data validators category covers the formats and identifiers used in software development, system administration, and data engineering — 15 validators spanning structured document formats, network identifiers, regular expressions, and scheduling syntax. These are the tools developers reach for when debugging an unexpected validation failure, verifying a format before writing code around it, or checking a value copied from an external system.

Structured document validation

The JSON Validator, XML Validator, YAML Validator, and HTML Validator check the most widely used data and markup formats. All four use full parsers — not just regex pattern matching — and report errors with line and column positions. A missing closing bracket in JSON, a tab character in YAML indentation, an unclosed tag in HTML — these are caught immediately with enough position information to navigate directly to the problem.

Network and identity validators

The Email Validator, URL Validator, IP Address Validator, MAC Address Validator, and Domain Name Validator cover the network-layer identifiers that appear in application configuration, logs, and form input. The UUID Validator identifies UUID versions from the version and variant bits — useful when debugging systems that mix UUID v1 and v4.

Developer tools

The Regex Tester validates both the pattern syntax and the test string match in one step. The Cron Expression Validator covers both 5-field Unix cron and 6-field Quartz format, with field-by-field error reporting. The Colour Code Validator handles all CSS colour formats and shows a live preview swatch. The Date Validator distinguishes between DD/MM/YYYY and MM/DD/YYYY to catch the date format errors that consistently slip through type-based validation. The ISBN Validator verifies both ISBN-10 and ISBN-13 checksums for book cataloguing.

Privacy

All validation runs in your browser — no data is transmitted or stored.