Regular expressions
Regular expressions are patterns that allow a bot to validate the format of user input — for example, to ensure that the input is a phone number rather than something else.
To compare using a regular expression, you need to set the match type to "RegEx match".
When collecting data, users often enter something other than what they're asked for. Here's a typical flow for validating a phone number input. If the user doesn't enter a valid phone number, the bot will prompt them to try again.
The phone number input block has two outgoing connections: one without any trigger, and the other with a trigger that uses a regular expression to match a phone number.
^(\+)?((\d{2,3}) ?\d|\d)(([ -]?\d)|( ?(\d{2,3}) ?)){5,12}\d$
This flow uses two connections to handle phone number validation:
Primary connection (valid number)
Trigger: A correctly formatted phone number.
Action: Adds the number to the application and proceeds.
Fallback connection (invalid input)
Priority: Lower than the primary connection.
Trigger: Any input that is not a valid phone number.
Action: Informs the user of the error and redirects them to try again.
This ensures that the user only progresses after providing valid data, while receiving immediate feedback on any errors.
A list of useful regular expressions:
Numeric Input only digits starting with 1: ^[1-9]+[0-9]*$
Numeric Input only digits starting with 0: ^[0-9]+[0-9]*$
Credit card number: [0-9]{13,16}
General phone number: ^(\+)?((\d{2,3}) ?\d|\d)(([ -]?\d)|( ?(\d{2,3}) ?)){5,12}\d$
Letters and numbers (Latin): ^[a-zA-Z0-9]+$
Domain (e.g. abcd.com): ^([a-zA-Z0-9]([a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]{2,6}$
URL (e.g. abcd.com): (https?):((//)|(\\\\))+[\w\d:#@%/;$()~_?\+-=\\\.&]*
IPv4: ((25[0-5]|2[0-4]\d|[01]?\d\d?)\.){3}(25[0-5]|2[0-4]\d|[01]?\d\d?)
IPv6: ((^|:)([0-9a-fA-F]{0,4})){1,8}$
User name (with a limit of 2-20 characters, which can be letters and numbers, the first character need to be a letter): ^[a-zA-Z][a-zA-Z0-9-_\.]{1,20}$
Password (Lowercase and uppercase latin letters, numbers): ^(?=.*\d)(?=.*[a-z])(?=.*[A-Z])(?!.*\s).*$
Strong password (uppercase, lowercase, numbers/special characters, min 8 characters): (?=^.{8,}$)((?=.*\d)|(?=.*\W+))(?![.\n])(?=.*[A-Z])(?=.*[a-z]).*$
Date in YYYY-MM-DD format: [0-9]{4}-(0[1-9]|1[012])-(0[1-9]|1[0-9]|2[0-9]|3[01]) UPD. Stricter date validation: (19|20)\d\d-((0[1-9]|1[012])-(0[1-9]|[12]\d)|(0[13-9]|1[012])-30|(0[13578]|1[02])-31)
Date in DD/MM/YYYY format: (0[1-9]|[12][0-9]|3[01])[- /.](0[1-9]|1[012])[- /.](19|20)\d\d
Date in DD.MM.YYYY format: (0[1-9]|[12][0-9]|3[01])[.](0[1-9]|1[012])[.](19|20)\d\d
Integer and floating-point numbers (dot as decimal separator) \-?\d+(\.\d{0,})?
UUID: ^[0-9A-Fa-f]{8}\-[0-9A-Fa-f]{4}\-[0-9A-Fa-f]{4}\-[0-9A-Fa-f]{4}\-[0-9A-Fa-f]{12}$
Latitude or Longitude: -?\d{1,3}\.\d+
UPD. E-mail: ^[-\w.]+@([A-z0-9][-A-z0-9]+\.)+[A-z]{2,4}$
UPD. URL ~^(?:(?:https?|ftp|telnet)://(?:[a-z0-9_-]{1,32}(?::[a-z0-9_-]{1,32})?@)?)?(?:(?:[a-z0-9-]{1,128}\.)+(?:ru|su|com|net|org|mil|edu|arpa|gov|biz|info|aero|inc|name|[a-z]{2})|(?!0)(?:(?!0[^.]|255)[0-9]{1,3}\.){3}(?!0|255)[0-9]{1,3})(?:/[a-z0-9.,_@%&?+=\~/-]*)?(?:#[^ '\"&]*)?$~i
UPD. Time in HH:MM:SS: format ^([0-1]\d|2[0-3])(:[0-5]\d){2}$
UPD. Mac-address: ([0-9a-fA-F]{2}([:-]|$)){6}$|([0-9a-fA-F]{4}([.]|$)){3}
There is a large number of regular expressions available. If you don’t find the one you need in this list, it’s a good idea to use a search engine.
You can conveniently test regular expressions on websites like: https://regex101.com/
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