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SEO019 · JSON-LD date format

Severity: info

Flags a value under a known date key (datePublished, dateModified, startDate, …) that is not ISO-8601. Reduced precision allowed by schema.org is accepted — year (2026), year-month (2026-06), full date, and date-time all pass.

Schema.org date properties expect ISO-8601; other formats may be ignored or misparsed.

"datePublished": "2026-06-26"