Each jurisdiction in this checker is classified into one of three rules based on its statute or regulator guidance: all-party consent (every participant must agree before recording), recording notice required (the GDPR pattern: a lawful basis plus informing participants), or one-party consent (one participant's consent, which can be the recorder's, suffices). Every classification links to at least one primary source, either the statute text on an official legislature site or the national data protection authority's guidance. The review date shown above is the date we last checked those sources, not a publishing date.
For cross-border pairs the checker applies a strictest-wins rule: if either side requires all-party consent, the verdict is all-party consent; otherwise, if either side requires a recording notice, the verdict is notice required. This is a conservative rule of thumb, not a conflict-of-laws analysis. Courts have applied the stricter jurisdiction's law to interstate calls, but no single answer covers every case, which is why cross-border results say "the safer course is" rather than stating a legal requirement. When either side of a call is outside our dataset, the checker says so and recommends local counsel instead of guessing.
Found an error, or a jurisdiction we should add? Tell us via the contact form on our homepage and we will review it against the primary sources.