HTML Entity Encoder & Decoder

Escape special characters for HTML or decode common entities back to text.

How it works

Encoding protects text from being interpreted as markup in a text context. It is not a complete XSS defense; use context-aware escaping in applications.

Replace &, <, >, ", and ' with named HTML entities.

Debugging scenario

Encode an untrusted display string containing ampersands, angle brackets and quotes, then place the result only in an HTML text-node test. For attributes, URLs, JavaScript, CSS or allowed rich HTML, use the framework encoder or sanitizer designed for that exact context.

How to interpret the result

Encoding replaces a small set of characters so text is not parsed as markup in a basic text context. Decoding reverses common entities and can recreate markup characters. Neither operation decides which elements, attributes, protocols or script behaviors are safe.

Input reference

Mode
Example default: Encode
Input
Example default: Sample input included

Common mistakes

  • Pasting secrets, credentials, customer records or other production data into a browser tool or shareable URL.
  • Using text-node escaping as a complete sanitizer for attributes, URLs, scripts, styles or rich HTML.
  • Treating a convenient preview as validation by the target runtime, parser, database or security control.

Before using the result

  1. Reduce the input to a synthetic example that still reproduces the behavior.
  2. Use context-aware framework escaping and an allowlist sanitizer where markup is permitted.
  3. Add the accepted input and expected output to the project regression tests before release.

Questions to check before production use

Does encoding sanitize HTML?

No. It escapes text for a context; it does not remove unsafe HTML or scripts.

Is input sent to a server?

No. Processing runs in the browser.

Independent developer utility. Review output before using it in production.

Detailed developer guide

Time, URLs and web interoperability: test boundaries, not appearances

Web values often look readable while carrying hidden unit, context or compatibility assumptions. This guide traces each value through the system that actually consumes it.

Read the guide