A structured-data date or duration is malformed
In the reportDate or duration value is not valid ISO 8601
structured_data_invalid_date_format · Issue
A captured temporal property contains a value that fails the supported ISO 8601 grammar.
Severity: Low. Correct the value when updating the page.
Why it matters
Structured-data consumers need a machine-readable date, time or duration to interpret this property.
What to do
- Read the property, failing substring and parser reason in the finding.
- Use a calendar date such as 2024-01-05, a datetime such as 2024-01-05T08:00:00+08:00, a time such as 08:00:00, or a duration such as PT1M54S appropriate for that property.
When to leave it as it is: Keep a legitimate text or numeric alternative where the property permits it; do not rewrite it as a date merely to satisfy a parser.
What we read
We read the page’s captured HTML and its JSON-LD, Microdata and RDFa declarations without executing JavaScript or fetching remote contexts. The finding preserves the property, validated value, original declaration and source byte positions.
Incomplete capture, an unresolved reference, contradictory values or a form outside the supported parser means not checked. It never demonstrates a correction.
We distinguish Date, DateTime, Time, Duration and interval properties, including explicitly typed literals. A local datetime without a timezone is a separate notice, not a malformed-date issue.
For Microdata temporal values, a captured content attribute supplies the machine value while the original visible property value remains in evidence.
Example & evidence
Illustrative correction; this is not a live audit.
"datePublished": "2024/01/05""datePublished": "2024-01-05"Confirm & check again
Check for yourself: Compare the reported property with the HTML served at this URL. Validate the corrected markup with the appropriate structured-data test.
Check again: Full audit — Run another full site audit. A correction is confirmed only for the same page with sufficient captured coverage and no remaining violation. Missing coverage does not close the finding.
Limits & sources
Week dates, ordinal/basic forms, expanded years, leap seconds and other unimplemented alternatives remain not checked rather than being reported as invalid.
This is a temporal value check, not a complete ISO conformance or rich-result eligibility validator. A property with an unconfirmed text/number alternative is not guessed to be malformed.
Confidence: High The finding records an exact offline validation reason. It does not establish Google indexing, ranking or rich-result display.
Sources
- Google, Article structured data — Documents ISO datetime values for article publication and modification. Checked 3 October 2026.
- Schema.org, Duration — Defines duration values and their temporal properties. Checked 3 October 2026.
- Schema.org, Time — Defines clock-time values and their properties. Checked 3 October 2026.
Editorial review: 2 November 2026