IsEmailAddress

Runtime verified Differs from official docs Test scripts included

Syntax

IsEmailAddress(value)  →  boolean

1 argument — exactly

Parameters

Name	Type	Required	Description
`value`	string	Yes	Value to validate; trim it first, as a leading or trailing space fails

Example

%%[ VAR @ok SET @ok = IsEmailAddress("tomas.q@example.com") ]%%
%%=v(@ok)=%%

Renders True.

Validating a form field means trimming it first — the raw value from a query string keeps its spaces, and a space is enough to fail the check:

%%[
  VAR @input, @ok
  SET @input = Trim(RequestParameter("email"))
  SET @ok = IsEmailAddress(@input)
]%%
%%=IIf(@ok, "thanks", "please check that address")=%%

Return value

boolean — True for a syntactically valid address, False otherwise.

Both literals were produced in the same render, as the capitalised words True and False. They are genuine booleans: each compares equal to the corresponding boolean value, so IIf and IF consume the result directly.

Behaviour

The check is syntax only. A well-formed address at a domain that resolves to nothing still returns True, so nothing here says the mailbox can receive mail.

A leading or trailing space fails. IsEmailAddress(" tomas.q@example.com") and the same address with a trailing space both return False, while the trimmed form returns True. No source mentions this, and an untrimmed form field is the usual way to meet it.

Local-part decoration is fine. A plus tag, dots, hyphens, underscores and digits are all accepted — a.b-c_d+e9@x-y.z.example.museum returns True.

Multi-label domains are accepted. tomas.q@mail.corp.example.com returns True.

A number does not abort the call. IsEmailAddress(123) returns False, as does the empty string.

Which inputs are accepted

Call	Renders
`IsEmailAddress("tomas.q@example.com")`	`True`
`IsEmailAddress("tomas.q+news@example.com")`	`True`
`IsEmailAddress("tomas.q@mail.corp.example.com")`	`True`
`IsEmailAddress("a.b-c_d+e9@x-y.z.example.museum")`	`True`
`IsEmailAddress("tomas.q@example")`	`False`
`IsEmailAddress("tomas.q.example.com")`	`False`
`IsEmailAddress(" tomas.q@example.com")`	`False`
`IsEmailAddress("tomas.q@example.com ")`	`False`
`IsEmailAddress("a@b@example.com")`	`False`
`IsEmailAddress("@example.com")`	`False`
`IsEmailAddress("a@.com")`	`False`
`IsEmailAddress("")`	`False`

A domain with no top-level domain is rejected

The official reference lists an address whose domain is a single label — no .com, no dot at all — as a valid result, with a note that such domains do exist. The engine returns False for that shape. Every other example in the same table matched what the engine did. See the differs-from-docs card.

Show test script

%%[
  VAR @b
  SET @b = RequestParameter("b")

  /* known-good control: renders on every request, so a run of HTTP 422s
     can be told apart from a broken deploy */
  OutputLine(Concat("CTRL=[", Uppercase("ok"), "]"))

  /* the accepted/rejected matrix - safe on every request */
  OutputLine(Concat("--- E start ---"))
  OutputLine(Concat("E1_valid=[", IsEmailAddress("tomas.q@example.com"), "]"))
  OutputLine(Concat("E2_plustag=[", IsEmailAddress("tomas.q+news@example.com"), "]"))
  OutputLine(Concat("E3_subdomain=[", IsEmailAddress("tomas.q@mail.corp.example.com"), "]"))
  OutputLine(Concat("E4_no_at=[", IsEmailAddress("tomas.q.example.com"), "]"))
  OutputLine(Concat("E5_no_tld=[", IsEmailAddress("tomas.q@example"), "]"))
  OutputLine(Concat("E6_lead_space=[", IsEmailAddress(" tomas.q@example.com"), "]"))
  OutputLine(Concat("E7_trail_space=[", IsEmailAddress("tomas.q@example.com "), "]"))
  OutputLine(Concat("E8_absurd=[", IsEmailAddress("a.b-c_d+e9@x-y.z.example.museum"), "]"))
  OutputLine(Concat("E9_double_at=[", IsEmailAddress("a@b@example.com"), "]"))
  OutputLine(Concat("E10_no_local=[", IsEmailAddress("@example.com"), "]"))
  OutputLine(Concat("E11_no_sld=[", IsEmailAddress("a@.com"), "]"))
  OutputLine(Concat("--- E done ---"))

  /* the empty string, in its own branch: the sibling IsCHTMLBrowser aborts
     on it, so the four functions must not share one empty-string branch */
  IF @b == "e_empty" THEN
    OutputLine(Concat("--- e_empty start ---"))
    OutputLine(Concat("E_EMPTY=[", IsEmailAddress(""), "]"))
    OutputLine(Concat("--- e_empty done ---"))
  ENDIF

  /* a non-string argument */
  IF @b == "g_num" THEN
    OutputLine(Concat("--- g_num start ---"))
    OutputLine(Concat("E_NUM=[", IsEmailAddress(123), "]"))
    OutputLine(Concat("--- g_num done ---"))
  ENDIF

  /* the rendered literals compared against real booleans */
  IF @b == "g_tok" THEN
    OutputLine(Concat("--- g_tok start ---"))
    OutputLine(Concat("E_EQTRUE=[", IIf(IsEmailAddress("tomas.q@example.com") == true, "matches-true", "no"), "]"))
    OutputLine(Concat("E_EQFALSE=[", IIf(IsEmailAddress("nope") == false, "matches-false", "no"), "]"))
    OutputLine(Concat("--- g_tok done ---"))
  ENDIF
]%%

OutputLine needs Concat

Every marker and label in the test script goes through Concat(...), including single-argument ones. A bare string literal passed to OutputLine renders an empty line while the page still returns HTTP 200, so the marker silently vanishes.

Availability

Platform	Available
Marketing Cloud Engagement	Yes
Marketing Cloud Next	No