> ## Documentation Index > Fetch the complete documentation index at: https://new.docs.falkordb.com/llms.txt > Use this file to discover all available pages before exploring further. # FLEX Function Reference > Reference for FLEX, FalkorDB's open-source community UDF package with text, date, JSON, map, collection, bitwise, and similarity utilities. FLEX is FalkorDB's open source community UDF package, available at [github.com/FalkorDB/flex](https://github.com/FalkorDB/flex).\ It contains a variety of useful functionality, including: * String and set similarity metrics for fuzzy matching and comparison * Date and time manipulation, formatting, and parsing * Low-level bitwise operations on integers We welcome contributions to extend this library with additional functionality. The following sections document all FLEX (FalkorDB Library for Extensions) functions. ## Function Categories ### Similarity Functions (`flex.sim.*`) Set similarity metrics for fuzzy matching and comparison. | Function | Description | | -------------------------------------------- | ----------------------------------------------------- | | [sim.jaccard](/udfs/flex/similarity/jaccard) | Calculate Jaccard similarity coefficient between sets | ### Text Functions (`flex.text.*`) String manipulation, formatting, case conversion utilities, and string similarity metrics. | Function | Description | | ----------------------------------------------------- | ------------------------------------------------- | | [text.capitalize](/udfs/flex/text/capitalize) | Capitalize the first character of a string | | [text.decapitalize](/udfs/flex/text/decapitalize) | Lowercase the first character of a string | | [text.swapCase](/udfs/flex/text/swapCase) | Swap the case of all characters in a string | | [text.camelCase](/udfs/flex/text/camelCase) | Convert string to camelCase format | | [text.upperCamelCase](/udfs/flex/text/upperCamelCase) | Convert string to UpperCamelCase (PascalCase) | | [text.snakeCase](/udfs/flex/text/snakeCase) | Convert string to snake\_case format | | [text.format](/udfs/flex/text/format) | Format string with placeholder substitution | | [text.indexOf](/udfs/flex/text/indexOf) | Find first occurrence of substring | | [text.indexesOf](/udfs/flex/text/indexesOf) | Find all occurrences of substring | | [text.join](/udfs/flex/text/join) | Join array elements with delimiter | | [text.lpad](/udfs/flex/text/lpad) | Pad string on the left to target length | | [text.rpad](/udfs/flex/text/rpad) | Pad string on the right to target length | | [text.regexGroups](/udfs/flex/text/regexGroups) | Extract regex matches and capture groups | | [text.repeat](/udfs/flex/text/repeat) | Repeat string multiple times | | [text.replace](/udfs/flex/text/replace) | Replace text using regex pattern | | [text.jaroWinkler](/udfs/flex/text/jaroWinkler) | Compute Jaro-Winkler similarity for short strings | | [text.levenshtein](/udfs/flex/text/levenshtein) | Compute Levenshtein edit distance between strings | ### Collection Functions (`flex.coll.*`) Operations on lists and arrays including set operations and transformations. | Function | Description | | -------------------------------------------------------- | ----------------------------------------------- | | [coll.zip](/udfs/flex/collections/zip) | Combine two lists element-by-element into pairs | | [coll.union](/udfs/flex/collections/union) | Combine lists and return unique elements | | [coll.intersection](/udfs/flex/collections/intersection) | Find common elements between lists | | [coll.shuffle](/udfs/flex/collections/shuffle) | Randomly shuffle list elements | | [coll.frequencies](/udfs/flex/collections/frequencies) | Count frequency of each element in list | ### Map Functions (`flex.map.*`) Map/object manipulation for property management and transformation. | Function | Description | | ------------------------------------------- | -------------------------------------- | | [map.merge](/udfs/flex/map/merge) | Shallow merge multiple maps | | [map.fromPairs](/udfs/flex/map/fromPairs) | Convert list of key-value pairs to map | | [map.submap](/udfs/flex/map/submap) | Extract subset of keys from map | | [map.removeKey](/udfs/flex/map/removeKey) | Remove single key from map | | [map.removeKeys](/udfs/flex/map/removeKeys) | Remove multiple keys from map | ### JSON Functions (`flex.json.*`) JSON serialization and parsing utilities. | Function | Description | | ------------------------------------------------- | ------------------------------ | | [json.toJson](/udfs/flex/json/toJson) | Serialize value to JSON string | | [json.fromJsonMap](/udfs/flex/json/fromJsonMap) | Parse JSON string to map | | [json.fromJsonList](/udfs/flex/json/fromJsonList) | Parse JSON string to list | ### Date Functions (`flex.date.*`) Date and time manipulation, formatting, and parsing. | Function | Description | | --------------------------------------------- | ------------------------------------------------- | | [date.format](/udfs/flex/date/format) | Format date/time with pattern and timezone | | [date.parse](/udfs/flex/date/parse) | Parse date/time string with optional pattern | | [date.truncate](/udfs/flex/date/truncate) | Truncate date to specific unit (day, month, etc.) | | [date.toTimeZone](/udfs/flex/date/toTimeZone) | Convert date to timezone offset | ### Bitwise Functions (`flex.bitwise.*`) Low-level bitwise operations on integers. | Function | Description | | --------------------------------------------------- | ---------------------------------------- | | [bitwise.and](/udfs/flex/bitwise/and) | Bitwise AND operation | | [bitwise.or](/udfs/flex/bitwise/or) | Bitwise OR operation | | [bitwise.xor](/udfs/flex/bitwise/xor) | Bitwise XOR (exclusive OR) operation | | [bitwise.not](/udfs/flex/bitwise/not) | Bitwise NOT (one's complement) operation | | [bitwise.shiftLeft](/udfs/flex/bitwise/shiftLeft) | Left bit shift operation | | [bitwise.shiftRight](/udfs/flex/bitwise/shiftRight) | Right bit shift with sign extension | ## Common Use Cases ### Data Cleaning and Normalization * `text.camelCase`, `text.snakeCase` - Normalize field names * `text.replace` - Remove or sanitize unwanted characters * `coll.union` - Deduplicate lists ### Fuzzy Matching and Search * `text.levenshtein` - Find similar strings with edit distance * `text.jaroWinkler` - Match names and short strings * `sim.jaccard` - Compare sets and tag similarity ### Data Aggregation and Analysis * `date.truncate` - Group by time periods * `coll.frequencies` - Count occurrences * `map.submap` - Select relevant fields ### API and Data Exchange * `json.toJson`, `json.fromJsonMap` - JSON serialization * `map.removeKeys` - Filter sensitive data * `text.format` - Build formatted messages ### Permission and Flag Management * `bitwise.and`, `bitwise.or` - Check and set permission flags * `bitwise.xor` - Toggle flags ## Frequently Asked Questions FLEX (FalkorDB Library for Extensions) is FalkorDB's open-source community UDF package. It provides ready-to-use functions for text manipulation, date/time handling, JSON processing, collections, maps, bitwise operations, and similarity metrics. FLEX functions use the namespace pattern `flex..()`. For example: `flex.text.camelCase('hello world')` or `flex.sim.jaccard(list1, list2)`. Yes. FLEX is available at [github.com/FalkorDB/flex](https://github.com/FalkorDB/flex) and must be loaded into your FalkorDB instance as a UDF library before use. Yes! FLEX is open source and welcomes community contributions. Visit the [FLEX GitHub repository](https://github.com/FalkorDB/flex) to submit new functions or improvements.