Email HTML Entity Obfuscator

Encode each email-address code point as a decimal HTML character reference for presentation, without claiming spam protection.

Description

HTML character references can encode visible address characters in source while rendering familiar text.

HTML character references can encode visible address characters in source while rendering familiar text. That transformation is presentation obfuscation rather than encryption or spam prevention.^[1]

Encode each email-address code point as a decimal HTML character reference for presentation, without claiming spam protection.

When to use Email HTML Entity Obfuscator

Use this tool to encode each email-address code point as a decimal HTML character reference for presentation, without claiming spam protection.

Choose the URL, decoded source text, header value or explicit byte list requested by this tool. Paste the complete relevant input and follow its parsing and encoding conventions.

How to use Email HTML Entity Obfuscator and understand its results

Choose the URL, decoded source text, header value or explicit byte list requested by this tool. Paste the complete relevant input and follow its parsing and encoding conventions.
Enter email using the field table and calculation rules, then run the tool.
Read encoded. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
email	Email address to encode.	string; maximum length: 1000000	Required

Enter a string with exactly one @, nonempty sides and no whitespace. The tool iterates Unicode code points and emits a decimal semicolon-terminated HTML reference for each. Read or copy the resulting encoded string for an appropriate HTML text context.

encoded=concatenate '&#'+UnicodeCodePoint+';' for each address character

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
encoded	HTML numeric character references.	string; maximum length: 1000000

json

{
  "input": {
    "email": "a@example.com"
  },
  "output": {
    "encoded": "&#97;&#64;&#101;&#120;&#97;&#109;&#112;&#108;&#101;&#46;&#99;&#111;&#109;"
  }
}

Limitations and assumptions

The address check is intentionally simple and does not validate mailbox syntax, deliverability or domain registration. Ordinary parsers and scrapers can recover the address.

Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Extremely large text inputs are rejected. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Meta Tag Parser: Extract named meta entries from HTML source in document order, preserving repeated keys. For a complementary task, use Unicode Domain to ASCII: Normalize a Unicode domain using WHATWG URL IDNA processing and return its ASCII hostname without performing DNS lookup.

References

Email HTML Entity Obfuscator — tool.io

Similar or alternative tools

Meta Tag Parser
Extract named meta entries from HTML source in document order, preserving repeated keys.
Unicode Domain to ASCII
Normalize a Unicode domain using WHATWG URL IDNA processing and return its ASCII hostname without performing DNS lookup.