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Some entities need to match patterns rather than specific terms.
For example, national identification numbers, IDs, license plates, and so on.
With regexp entities,
you can provide
regular expressions
for matching.
Compound regular expressions
Each regexp entity corresponds to a single pattern,
but you can provide multiple regular expressions
if they all represent variations of a single pattern.
During agent training, all regular expressions of a single entity are combined
with the alternation operator (|) to form one compound regular expression.
For example, if you provide the following regular expressions for a phone number:
The ordering of regular expressions matters.
Each of the regular expressions in the compound regular expression are processed in order.
Searching stops once a valid match is found.
For example, for an end user expression of "Seattle":
Sea|Seattle matches "Sea"
Seattle|Sea matches "Seattle"
Special handling for speech recognition
If your agent uses speech recognition
(also known as audio input, speech-to-text, or STT),
your regular expressions will need special handling when matching letters and numbers.
A spoken end-user utterance is first processed by the speech recognizer before entities are matched.
When an utterance contains a series of letters or numbers,
the recognizer may pad each character with spaces.
In addition, the recognizer may interpret digits in word form.
For example, an end-user utterance of "My ID is 123"
may be recognized as any of the following:
"My ID is 123"
"My ID is 1 2 3"
"My ID is one two three"
To accommodate three digit numbers,
you could use the following regular expressions:
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-07 UTC."],[[["\u003cp\u003eRegexp entities allow matching patterns rather than specific terms, useful for national IDs, license plates, and other structured data.\u003c/p\u003e\n"],["\u003cp\u003eMultiple regular expressions can be combined into a single compound regular expression using the alternation operator (\u003ccode\u003e|\u003c/code\u003e).\u003c/p\u003e\n"],["\u003cp\u003eThe order of regular expressions in a compound regular expression is important, as the system stops searching after the first valid match.\u003c/p\u003e\n"],["\u003cp\u003eSpecial handling is needed for regexp entities when using speech recognition, as the recognizer may add spaces or use word forms for digits.\u003c/p\u003e\n"],["\u003cp\u003eThere are limitations to using regexp entities, including the exclusion of fuzzy matching, a maximum of 50 regexp entities per agent, and a 2000-character limit for the compound regular expression.\u003c/p\u003e\n"]]],[],null,["# Regexp entities\n\nSome entities need to match patterns rather than specific terms.\nFor example, national identification numbers, IDs, license plates, and so on.\nWith *regexp entities* ,\nyou can provide\n[regular expressions](https://github.com/google/re2/wiki/Syntax)\nfor matching.\n\nCompound regular expressions\n----------------------------\n\nEach regexp entity corresponds to a single pattern,\nbut you can provide multiple regular expressions\nif they all represent variations of a single pattern.\nDuring agent training, all regular expressions of a single entity are combined\nwith the alternation operator (`|`) to form one *compound regular expression*.\n\nFor example, if you provide the following regular expressions for a phone number:\n\n- `^[2-9]\\d{2}-\\d{3}-\\d{4}$`\n- `^(1?(-?\\d{3})-?)?(\\d{3})(-?\\d{4})$`\n\nThe compound regular expression becomes:\n\n- `^[2-9]\\d{2}-\\d{3}-\\d{4}$|^(1?(-?\\d{3})-?)?(\\d{3})(-?\\d{4})$`\n\nThe ordering of regular expressions matters.\nEach of the regular expressions in the compound regular expression are processed in order.\nSearching stops once a valid match is found.\nFor example, for an end user expression of \"Seattle\":\n\n- `Sea|Seattle` matches \"Sea\"\n- `Seattle|Sea` matches \"Seattle\"\n\nSpecial handling for speech recognition\n---------------------------------------\n\n| **Note:** Enabling [auto speech adaptation](/dialogflow/cx/docs/concept/speech-adaptation) is recommended when using regexp entities. Also see the speech adaptation [regexp-specific guidelines](/dialogflow/cx/docs/concept/speech-adaptation#regexp-entities).\n\nIf your agent uses speech recognition\n(also known as audio input, speech-to-text, or STT),\nyour regular expressions will need special handling when matching letters and numbers.\nA spoken end-user utterance is first processed by the speech recognizer before entities are matched.\nWhen an utterance contains a series of letters or numbers,\nthe recognizer may pad each character with spaces.\nIn addition, the recognizer may interpret digits in word form.\nFor example, an end-user utterance of \"My ID is 123\"\nmay be recognized as any of the following:\n\n- \"My ID is 123\"\n- \"My ID is 1 2 3\"\n- \"My ID is one two three\"\n\nTo accommodate three digit numbers,\nyou could use the following regular expressions: \n\n```\n\\d{3}\n``` \n\n```\n\\d \\d \\d\n``` \n\n```\n(zero|one|two|three|four|five|six|seven|eight|nine) (zero|one|two|three|four|five|six|seven|eight|nine) (zero|one|two|three|four|five|six|seven|eight|nine)\n```\n\nCreate a regexp entity\n----------------------\n\n### Console\n\n1. Open the [Dialogflow CX console](https://dialogflow.cloud.google.com/cx/projects).\n2. Choose your GCP project.\n3. Select your agent.\n4. Select the **Manage** tab.\n5. Click **Entity Types**.\n6. Click **Create**.\n7. Check **Regexp entities**.\n8. Complete remaining fields.\n9. Click **Save**.\n\n### API\n\nSet the `EntityType.kind` field to `KIND_REGEXP`.\n\n\nGo to the EntityType API reference \n**Select a protocol and version for the EntityType reference:**\n\nClose\n\n\u003cbr /\u003e\n\nLimitations\n-----------\n\nThe following limitations apply:\n\n- [Fuzzy matching](/dialogflow/cx/docs/concept/entity-fuzzy) cannot be enabled for regexp entities. These features are mutually exclusive.\n- Each agent can have a maximum of 50 regexp entities.\n- The [compound regular expression](#compound) for an entity has a maximum length of 2000 characters."]]
