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Formatters

HTML Formatter / Minifier

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Validators

HTML Validator

JSON Validator

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Regular Expression Tester

Cryptography and Security

Hash Generator

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Bcrypt Generator / Checker

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Encoders and Decoders

URL Encoder / Decoder

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Base32 Encoder / Decoder

Base58 Encoder / Decoder

Base64 Encoder / Decoder

Base64 Image Encoder / Decoder

JWT Decoder

Converters

JavaScript / JSON Converter

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Text / HEX Converter

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EXIF Viewer

Network Tools

My IP

IP Lookup

IP / Number Converter

CIDR / IP Converter

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About

Contact

Validators

HTML Validator

server

Input 1 - Browse HTML File

Choose file...

Input 2 - Enter HTML

Options

Fragment

HTML Validator is a free online developer tool to validate HTML code against the W3C standards as known as HTML linter instantly. Supports partial HTML code validation.

You can either browse an HTML file, fetch HTML code from a URL, or paste HTML code manually, and then click the validate button. The results will be displayed accordingly when the process is done.

Basically, there are two types of result messages: warning and error

Warning - A suggestion to fix your HTML code. For instance, an HTML attribute that can be omitted.

Error - An error in your HTML code that's against the W3C standards. You're encouraged to fix it.

Each message comes with a line number and excerpt code indicating where a warning or an error is located.

Optionally, you can partially validate HTML code by enabling the fragment option so that the HTML code will be treated as part of an HTML document instead of a full one.

Related Tools

JSON Validator

Validates JSON data against the JSON specification instantly as known as JSON linter. Errors including line numbers and excerpt code will be printed if any.

YAML Validator

Validates YAML data against the YAML specification instantly as known as YAML linter. Errors including line numbers and excerpt code will be printed if any.

Credit Card Validator

Safely validates a credit card number instantly to check if it's a valid card and find the card type. Completely works on your browser for your safety and privacy.

Regular Expression Tester

Tests a regular expression against any string instantly with matches highlighted including a cheat sheet and a reference.