{
"id": "jmespath-custom-functions",
"title": "JMESPath custom functions",
"url": "https://redis.io/docs/latest/integrate/write-behind/reference/jmespath-custom-functions/",
"summary": "JMESPath custom function reference",
"tags": [
"docs",
"integrate",
"rs",
"rdi"
],
"last_updated": "2026-04-01T08:10:08-05:00",
"page_type": "content",
"content_hash": "0cc0698b042571514d966343a080ac07b09748f215ab39815b55309df9b2a63a",
"sections": [
{
"id": "content",
"title": "Content",
"role": "content",
"text": "| Function | Description | Example | Comments |\n| -------------------- | ----------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| `base64_decode` | Decodes a base64(RFC 4648) encoded string | Input: `{\"encoded\": \"SGVsbG8gV29ybGQh\"}`
Expression: `base64_decode(encoded)`
Output: `Hello World!` | |\n| `capitalize` | Capitalizes all the words in the string | Input: `{\"name\": \"john doe\"}`
Expression: `capitalize(name)`
Output: `John Doe` | |\n| `concat` | Concatenates an array of variables or literals | Input: `{\"fname\": \"john\", \"lname\": \"doe\"}`
Expression: `concat([fname, ' ' ,lname])`
Output: `john doe` | This is equivalent to the more verbose built-in expression: `' '.join([fname,lname])` |\n| `filter_entries` | Filters entries in a dictionary (object) using the given JMESPath predicate | Input: `{ \"name\": \"John\", \"age\": 30, \"country\": \"US\", \"score\": 15}`
Expression: `` filter_entries(@, `key == 'name' \\|\\| key == 'age'`)``
Output:`{\"name\": \"John\", \"age\": 30 }` | |\n| `from_entries` | Converts an array of objects with `key` and `value` properties into a single object | Input: `[{\"key\": \"name\", \"value\": \"John\"}, {\"key\": \"age\", \"value\": 30}, {\"key\": \"city\", \"value\": null}]`
Expression: `from_entries(@)`
Output: `{\"name\": \"John\", \"age\": 30, \"city\": null}` | |\n| `hash` | Calculates a hash using the `hash_name` hash function and returns its hexadecimal representation | Input: `{\"some_str\": \"some_value\"}`
Expression: `hash(some_str, `sha1`)`
Output: `8c818171573b03feeae08b0b4ffeb6999e3afc05` | Supported algorithms: sha1 (default), sha256, md5, sha384, sha3_384, blake2b, sha512, sha3_224, sha224, sha3_256, sha3_512, blake2s |\n| `in` | Checks if an element matches any value in a list of values | Input: `{\"el\": \"b\"}`
Expression: `in(el, `[\"a\", \"b\", \"c\"]`)`
Output: `True` | |\n| `left` | Returns a specified number of characters from the start of a given text string | Input: `{\"greeting\": \"hello world!\"}`
Expression: `left(greeting, `5`)`
Output: `hello` | |\n| `lower` | Converts all uppercase characters in a string into lowercase characters | Input: `{\"fname\": \"John\"}`
Expression: `lower(fname)`
Output: `john` | |\n| `mid` | Returns a specified number of characters from the middle of a given text string | Input: `{\"greeting\": \"hello world!\"}`
Expression: `mid(greeting, `4`, `3`)`
Output: `o w` | |\n| `json_parse` | Returns parsed object from the given json string | Input: `{\"data\": '{\"greeting\": \"hello world!\"}'}`
Expression: `parse_json(data)`
Output: `{\"greeting\": \"hello world!\"}` | |\n| `regex_replace` | Replaces a string that matches a regular expression | Input: `{\"text\": \"Banana Bannnana\"}`
Expression: `regex_replace(text, 'Ban\\w+', 'Apple Apple')`
Output: `Apple Apple` | |\n| `replace` | Replaces all the occurrences of a substring with a new one | Input: `{\"sentence\": \"one four three four!\"}`
Expression: `replace(sentence, 'four', 'two')`
Output: `one two three two!` | |\n| `right` | Returns a specified number of characters from the end of a given text string | Input: `{\"greeting\": \"hello world!\"}`
Expression: `right(greeting, `6`)`
Output: `world!` | |\n| `split` | Splits a string into a list of strings after breaking the given string by the specified delimiter (comma by default) | Input: `{\"departments\": \"finance,hr,r&d\"}`
Expression: `split(departments)`
Output: `['finance', 'hr', 'r&d']` | Default delimiter is comma - a different delimiter can be passed to the function as the second argument, for example: `split(departments, ';')` |\n| `time_delta_days` | Returns the number of days between a given `dt` and now (positive) or the number of days that have passed from now (negative) | Input: `{\"dt\": '2021-10-06T18:56:16.701670+00:00'}`
Expression: `time_delta_days(dt)`
Output: `365` | If `dt` is a string, ISO datetime (2011-11-04T00:05:23+04:00, for example) is assumed. If `dt` is a number, Unix timestamp (1320365123, for example) is assumed. |\n| `time_delta_seconds` | Returns the number of seconds between a given `dt` and now (positive) or the number of seconds that have passed from now (negative) | Input: `{\"dt\": '2021-10-06T18:56:16.701670+00:00'}`
Expression: `time_delta_days(dt)`
Output: `31557600` | If `dt` is a string, ISO datetime (2011-11-04T00:05:23+04:00, for example) is assumed. If `dt` is a number, Unix timestamp (1320365123, for example) is assumed. |\n| `to_entries` | Converts a given object into an array of objects with `key` and `value` properties | Input: `{\"name\": \"John\", \"age\": 30, \"city\": null}`
Expression: `to_entries(@)`
Output: `[{\"key\": \"name\", \"value\": \"John\"}, {\"key\": \"age\", \"value\": 30}, {\"key\": \"city\", \"value\": null}]` | |\n| `upper` | Converts all lowercase characters in a string into uppercase characters | Input: `{\"fname\": \"john\"}`
Expression: `upper(fname)`
Output: `JOHN` | |\n| `uuid` | Generates a random UUID4 and returns it as a string in standard format | Input: None
Expression: `uuid()`
Output: `3264b35c-ff5d-44a8-8bc7-9be409dac2b7` | |"
}
],
"examples": []
}