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Date formats supported by Siteimprove Policy

Kate Sygrove avatar
By Kate Sygrove

Supported date formats

Only three formats are supported: Variants of ISO 8601, RFCs 1123, 5322 and 2822 as well as Unix Epoch dates.

Group Formats Examples Notes
 ISO 8601







Supports three granularities: Date, date with time, and date with time and fractions.
The timezone identifier is Z for UTC, or can be provided as +01:00 or +0100.
No timezone identifier is interpreted as UTC.
Time, if provided, must be in 24-hour format.

ddd, dd, MMM yyyy HH:mm:ss GMT

ddd, dd, MMM yyyy HH:mm:ss K 


Mon, 15 Jun 2009 20:45:30 GMT

Mon, 15 Jun 2009 20:45:30 +0100
Mon, 15 Jun 2009 20:45:30 +01:00
Mon, 15 Jun 2009 20:45:30

Variants are commonly used for HTTP date headers, such as the Last-Modified header.
Day and month names must be in English, as per the RFCs.
No timezone identifier is interpreted as UTC.
Time must be in 24-hour format. 
Unix Epoch  A large whole number  1443052852 The number of seconds since 1st of January 1970 (also known as the Unix Epoch).
The date will be interpreted as UTC. 

This following table shows the built-in date formats that will be accepted by Policy in a range of programming languages:


Language/environment Format strings Documentation
.NET O, o, R, r Standard Date and Time Format Strings  
 RFCs c, r Date/Time Functions
Java N/A Java doesn't natively support ISO 8601, but the Joda-Time library does.
Learn more about Custom Formatters


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