What does the DMARC t= tag do?

DMARC `t=` Tag — Testing Mode (t)

The DMARC t tag (RFC 9989) signals that a domain is in testing mode. Receivers may treat p=reject as quarantine when t=y, enabling softer rollout without changing policy.

Importance
Optional

Tag
t=

Default
n

Example
t=y

✅ Valid Values

y Testing mode active. Receivers may soften enforcement.

n Normal enforcement (default). Not testing.

💬 What This Tag Does

Added in RFC 9989 (DMARCbis), the "t" tag signals that the domain is testing its DMARC policy. When set to "y", receivers may apply a less strict treatment — a p=reject policy might be handled as p=quarantine. This replaces the role that pct= served for gradual rollouts, without the complexity of percentage-based sampling.