Expression Language

The expression language is used for substitutions, text transformations, and simple conditions in builder blocks and message templates.

Expressions are written inside {...}.

Where Expressions Are Used

Expressions are available in two places:

• builder blocks;
• message templates.

Basic Syntax

Use an expression inside a text string when you want to insert a value:

Hello, {client.name}!

If a whole field contains only one expression, the full field value is taken from that expression:

{funnel.order_total}

When an expression is embedded inside normal text, its result is inserted into the final string.

Embedded expressions must return a simple value:

• string
• number
• boolean
• null

Rendering behavior:

• null becomes an empty string;
• true and false become the strings true and false;
• an object or array inside a normal text template causes an error.

Available Variables

Message Templates

Message templates can use:

• client.*
• chat.*
• operator.*
• message.*

The same values are also available through sys.*:

• sys.client.*
• sys.chat.*
• sys.operator.*
• sys.message.*

Builder Blocks

Builder blocks use system variables through sys.*:

• sys.client.*
• sys.chat.*
• sys.operator.*
• sys.message.*

Builder blocks can also use:

• funnel.<key>
• env.<KEY>

System Variables

Client

• client.name
• client.id
• client.external_id
• client.phone
• client.comment

Chat

• chat.id
• chat.status
• chat.channel

Operator

• operator.id

Message

• message.id
• message.text
• message.type
• message.direction

Client Custom Fields

Client custom fields are available as:

client.customfield.<field_key>

In builder blocks, the common form is:

sys.client.customfield.<field_key>

Funnel Variables

Use funnel variables for values collected or calculated inside the funnel:

funnel.order_total
funnel.stage_code
funnel.is_repeat_client

Funnel variable keys must:

• be lowercase;
• start with a letter;
• contain only letters, digits, and _.

Environment Variables

Use environment variables for configured values:

env.API_URL
env.COUNTRY_CODE

Environment variable names must:

• be uppercase;
• start with a letter;
• contain only letters, digits, and _.

Functions

Lowercase

Signature: lowercase(value): string

Converts a string to lowercase.

lowercase(message.text)

Uppercase

Signature: uppercase(value): string

Converts a string to uppercase.

uppercase(client.name)

Length

Signature: length(value): number

Returns the string length.

length(message.text)

Replace

Signature: replace(value, search, replace): string

Replaces all occurrences of a string.

replace(message.text, "hello", "hi")

Regex Replace

Signature: regex_replace(value, pattern, replacement): string

Replaces text with a regular expression.

regex_replace(message.text, '#^/start\\s+#', '')

If the regular expression is invalid, the expression returns an error.

Base64

Signature: base64(value): string

Encodes a string as Base64.

base64(client.id)

Operators

Supported operators:

• and
• or
• not
• ==
• !=
• >
• >=
• <
• <=
• +
• -
• *
• /
• %
• ~

Use ~ for string concatenation.

Conditions

Conditions can be used inside expressions to calculate the required value.

Supported comparisons and logical operators:

• ==
• !=
• >
• >=
• <
• <=
• and
• or
• not

Examples:

sys.client.customfield.tariff == "premium" and sys.chat.channel == "telegram"
length(message.text) > 10
sys.chat.channel == "telegram" ? "TG client" : "Other client"

Conditions also support:

• strings in single or double quotes;
• numbers;
• true, false, null;
• arrays: [1, 2, 3];
• in;
• matches;
• ternary expressions: condition ? a : b;
• null coalescing: a ?? b.