format

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In JSON documents, dates are represented as strings. Elasticsearch uses a set of preconfigured formats to recognize and parse these strings into a long value representing milliseconds-since-the-epoch in UTC.

Besides the built-in formats, your own custom formats can be specified using the familiar yyyy/MM/dd syntax:

resp = client.indices.create(
    index="my-index-000001",
    mappings={
        "properties": {
            "date": {
                "type": "date",
                "format": "yyyy-MM-dd"
            }
        }
    },
)
print(resp)
response = client.indices.create(
  index: 'my-index-000001',
  body: {
    mappings: {
      properties: {
        date: {
          type: 'date',
          format: 'yyyy-MM-dd'
        }
      }
    }
  }
)
puts response
res, err := es.Indices.Create(
	"my-index-000001",
	es.Indices.Create.WithBody(strings.NewReader(`{
	  "mappings": {
	    "properties": {
	      "date": {
	        "type": "date",
	        "format": "yyyy-MM-dd"
	      }
	    }
	  }
	}`)),
)
fmt.Println(res, err)
const response = await client.indices.create({
  index: "my-index-000001",
  mappings: {
    properties: {
      date: {
        type: "date",
        format: "yyyy-MM-dd",
      },
    },
  },
});
console.log(response);
PUT my-index-000001
{
  "mappings": {
    "properties": {
      "date": {
        "type":   "date",
        "format": "yyyy-MM-dd"
      }
    }
  }
}

Many APIs which support date values also support date math expressions, such as now-1m/d — the current time, minus one month, rounded down to the nearest day.

Custom date formats

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Completely customizable date formats are supported. The syntax for these is explained in DateTimeFormatter docs.

Differences in locale information between JDK versions

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There can be some differences in date formats between JDK versions and different locales. In particular, there can be differences in text strings used for textual date formats, and there can be differences in the results of week-date calculations.

There can be differences in text strings used by the following field specifiers:

  • B, E, G, O, a, v, z of any length
  • L, M, Q, q, c, e of length 3 or greater
  • Z of length 4

If the text format changes between Elasticsearch or JDK versions, it can cause significant problems with ingest, output, and re-indexing. It is recommended to always use numerical fields in custom date formats, which are not affected by locale information.

There can also be differences in week-date calculations using the Y, W, and w field specifiers. The underlying data used to calculate week-dates can vary depending on the JDK version and locale; this can cause differences in the calculated week-date for the same calendar dates. It is recommended that the built-in week-date formats are used, which will always use ISO rules for calculating week-dates.

In particular, there is a significant change in locale information between JDK releases 22 and 23. Elasticsearch will use the COMPAT locale database when run on JDK 22 and before, and will use the CLDR locale database when run on JDK 23 and above. This change can cause significant differences to the textual date formats accepted by Elasticsearch, and to calculated week-dates. If you are using affected specifiers, you may need to modify your ingest or output integration code to account for the differences between these two JDK versions.

Built-in formats

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Most of the below formats have a strict companion format, which means that year, month and day parts of the month must use respectively 4, 2 and 2 digits exactly, potentially prepending zeros. For instance a date like 5/11/1 would be considered invalid and would need to be rewritten to 2005/11/01 to be accepted by the date parser.

To use them, you need to prepend strict_ to the name of the date format, for instance strict_date_optional_time instead of date_optional_time.

These strict date formats are especially useful when date fields are dynamically mapped in order to make sure to not accidentally map irrelevant strings as dates.

The following tables lists all the defaults ISO formats supported:

epoch_millis
A formatter for the number of milliseconds since the epoch. Note, that this timestamp is subject to the limits of a Java Long.MIN_VALUE and Long.MAX_VALUE.
epoch_second
A formatter for the number of seconds since the epoch. Note, that this timestamp is subject to the limits of a Java Long.MIN_VALUE and Long. MAX_VALUE divided by 1000 (the number of milliseconds in a second).
date_optional_time or strict_date_optional_time

A generic ISO datetime parser, where the date must include the year at a minimum, and the time (separated by T), is optional. Examples: yyyy-MM-dd'T'HH:mm:ss.SSSZ or yyyy-MM-dd.

NOTE: When using `date_optional_time`, the parsing is lenient and will attempt to parse
numbers as a year (e.g. `292278994` will be parsed as a year). This can lead to unexpected results
when paired with a numeric focused format like `epoch_second` and `epoch_millis`.
It is recommended you use `strict_date_optional_time` when pairing with a numeric focused format.
strict_date_optional_time_nanos
A generic ISO datetime parser, where the date must include the year at a minimum, and the time (separated by T), is optional. The fraction of a second part has a nanosecond resolution. Examples: yyyy-MM-dd'T'HH:mm:ss.SSSSSSZ or yyyy-MM-dd.
basic_date
A basic formatter for a full date as four digit year, two digit month of year, and two digit day of month: yyyyMMdd.
basic_date_time
A basic formatter that combines a basic date and time, separated by a T: yyyyMMdd'T'HHmmss.SSSZ.
basic_date_time_no_millis
A basic formatter that combines a basic date and time without millis, separated by a T: yyyyMMdd'T'HHmmssZ.
basic_ordinal_date
A formatter for a full ordinal date, using a four digit year and three digit dayOfYear: yyyyDDD.
basic_ordinal_date_time
A formatter for a full ordinal date and time, using a four digit year and three digit dayOfYear: yyyyDDD'T'HHmmss.SSSZ.
basic_ordinal_date_time_no_millis
A formatter for a full ordinal date and time without millis, using a four digit year and three digit dayOfYear: yyyyDDD'T'HHmmssZ.
basic_time
A basic formatter for a two digit hour of day, two digit minute of hour, two digit second of minute, three digit millis, and time zone offset: HHmmss.SSSZ.
basic_time_no_millis
A basic formatter for a two digit hour of day, two digit minute of hour, two digit second of minute, and time zone offset: HHmmssZ.
basic_t_time
A basic formatter for a two digit hour of day, two digit minute of hour, two digit second of minute, three digit millis, and time zone off set prefixed by T: 'T'HHmmss.SSSZ.
basic_t_time_no_millis
A basic formatter for a two digit hour of day, two digit minute of hour, two digit second of minute, and time zone offset prefixed by T: 'T'HHmmssZ.
basic_week_date or strict_basic_week_date
A basic formatter for a full date as four digit weekyear, two digit week of weekyear, and one digit day of week: xxxx'W'wwe.
basic_week_date_time or strict_basic_week_date_time
A basic formatter that combines a basic weekyear date and time, separated by a T: xxxx'W'wwe'T'HHmmss.SSSZ.
basic_week_date_time_no_millis or strict_basic_week_date_time_no_millis
A basic formatter that combines a basic weekyear date and time without millis, separated by a T: xxxx'W'wwe'T'HHmmssZ.
date or strict_date
A formatter for a full date as four digit year, two digit month of year, and two digit day of month: yyyy-MM-dd.
date_hour or strict_date_hour
A formatter that combines a full date and two digit hour of day: yyyy-MM-dd'T'HH.
date_hour_minute or strict_date_hour_minute
A formatter that combines a full date, two digit hour of day, and two digit minute of hour: yyyy-MM-dd'T'HH:mm.
date_hour_minute_second or strict_date_hour_minute_second
A formatter that combines a full date, two digit hour of day, two digit minute of hour, and two digit second of minute: yyyy-MM-dd'T'HH:mm:ss.
date_hour_minute_second_fraction or strict_date_hour_minute_second_fraction
A formatter that combines a full date, two digit hour of day, two digit minute of hour, two digit second of minute, and three digit fraction of second: yyyy-MM-dd'T'HH:mm:ss.SSS.
date_hour_minute_second_millis or strict_date_hour_minute_second_millis
A formatter that combines a full date, two digit hour of day, two digit minute of hour, two digit second of minute, and three digit fraction of second: yyyy-MM-dd'T'HH:mm:ss.SSS.
date_time or strict_date_time
A formatter that combines a full date and time, separated by a T: yyyy-MM-dd'T'HH:mm:ss.SSSZ.
date_time_no_millis or strict_date_time_no_millis
A formatter that combines a full date and time without millis, separated by a T: yyyy-MM-dd'T'HH:mm:ssZ.
hour or strict_hour
A formatter for a two digit hour of day: HH
hour_minute or strict_hour_minute
A formatter for a two digit hour of day and two digit minute of hour: HH:mm.
hour_minute_second or strict_hour_minute_second
A formatter for a two digit hour of day, two digit minute of hour, and two digit second of minute: HH:mm:ss.
hour_minute_second_fraction or strict_hour_minute_second_fraction
A formatter for a two digit hour of day, two digit minute of hour, two digit second of minute, and three digit fraction of second: HH:mm:ss.SSS.
hour_minute_second_millis or strict_hour_minute_second_millis
A formatter for a two digit hour of day, two digit minute of hour, two digit second of minute, and three digit fraction of second: HH:mm:ss.SSS.
ordinal_date or strict_ordinal_date
A formatter for a full ordinal date, using a four digit year and three digit dayOfYear: yyyy-DDD.
ordinal_date_time or strict_ordinal_date_time
A formatter for a full ordinal date and time, using a four digit year and three digit dayOfYear: yyyy-DDD'T'HH:mm:ss.SSSZ.
ordinal_date_time_no_millis or strict_ordinal_date_time_no_millis
A formatter for a full ordinal date and time without millis, using a four digit year and three digit dayOfYear: yyyy-DDD'T'HH:mm:ssZ.
time or strict_time
A formatter for a two digit hour of day, two digit minute of hour, two digit second of minute, three digit fraction of second, and time zone offset: HH:mm:ss.SSSZ.
time_no_millis or strict_time_no_millis
A formatter for a two digit hour of day, two digit minute of hour, two digit second of minute, and time zone offset: HH:mm:ssZ.
t_time or strict_t_time
A formatter for a two digit hour of day, two digit minute of hour, two digit second of minute, three digit fraction of second, and time zone offset prefixed by T: 'T'HH:mm:ss.SSSZ.
t_time_no_millis or strict_t_time_no_millis
A formatter for a two digit hour of day, two digit minute of hour, two digit second of minute, and time zone offset prefixed by T: 'T'HH:mm:ssZ.
week_date or strict_week_date
A formatter for a full date as four digit weekyear, two digit week of weekyear, and one digit day of week: YYYY-'W'ww-e. This uses the ISO week-date definition.
week_date_time or strict_week_date_time
A formatter that combines a full weekyear date and time, separated by a T: YYYY-'W'ww-e'T'HH:mm:ss.SSSZ. This uses the ISO week-date definition.
week_date_time_no_millis or strict_week_date_time_no_millis
A formatter that combines a full weekyear date and time without millis, separated by a T: YYYY-'W'ww-e'T'HH:mm:ssZ. This uses the ISO week-date definition.
weekyear or strict_weekyear
A formatter for a four digit weekyear: YYYY. This uses the ISO week-date definition.
weekyear_week or strict_weekyear_week
A formatter for a four digit weekyear and two digit week of weekyear: YYYY-'W'ww. This uses the ISO week-date definition.
weekyear_week_day or strict_weekyear_week_day
A formatter for a four digit weekyear, two digit week of weekyear, and one digit day of week: YYYY-'W'ww-e. This uses the ISO week-date definition.
year or strict_year
A formatter for a four digit year: yyyy.
year_month or strict_year_month
A formatter for a four digit year and two digit month of year: yyyy-MM.
year_month_day or strict_year_month_day
A formatter for a four digit year, two digit month of year, and two digit day of month: yyyy-MM-dd.