# Expressions reference > Complete reference for Kustomer's expression languages. Covers every /#fn function, every Handlebars helper with its arguments and defaults, and the criteria format and operators used by queue rules and satisfaction surveys. Source: https://developer.kustomer.com/docs/workflows/expressions-reference Kustomer has three small expression languages. This page lists everything in each. | Language | Looks like | Used in | | ----------------------------------------- | ----------------------------------------------------------------------------------- | ----------------------------------------------------------- | | [Functions](#functions) | `"/#fn:parseInt,steps.1.custom.qtyStr"` | Workflow params and conditions. Returns typed values | | [Handlebars helpers](#handlebars-helpers) | `"{{{dateFormat steps.1.createdAt format='LL'}}}"` | Any workflow string that isn't a reference. Returns strings | | [Criteria](#criteria) | `{ "and": [{ "conversation_status": { "operator": "equals", "value": "open" } }] }` | Queue rules and satisfaction surveys | For how references, templates and conditions fit together, start with [Conditions and variables](https://developer.kustomer.com/docs/workflows/conditions-and-expressions). ## Functions A function call is a reference that starts with `/#fn:`. The parts are separated by commas, with no spaces: the function name, a path to the input value, then any arguments. ```text /#fn:,,, ``` Because commas separate the parts, arguments can't contain commas (`dateFormat`'s format is the one exception). The path is resolved like any reference, so `steps.1.custom.qtyStr` means `/#steps.1.custom.qtyStr`. Write it as a bare path: `/#fn:parseInt,steps.1.custom.qtyStr`, not `/#fn:parseInt,/#steps.1.custom.qtyStr`. Like any reference, a function call only works as the whole value of a param or condition operand. A function name that doesn't exist doesn't fail: it silently returns the input value unchanged, so check spelling carefully. | Function | Example | Returns | | ------------------------------- | ------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------ | | `parseInt` | `/#fn:parseInt,steps.1.custom.qtyStr` | An integer. `0` if the input is empty or not a number | | `parseFloat` | `/#fn:parseFloat,steps.1.attributes.data.total` | A number. `0` if the input is empty or not a number | | `parseBool` | `/#fn:parseBool,steps.1.attributes.data.vip` | `true` for `true` or `"true"` (any case), otherwise `false` | | `parseJSON` | `/#fn:parseJSON,steps.call.body` | The parsed object. `{}` if the string isn't valid JSON | | `dateFormat` | `/#fn:dateFormat,steps.1.createdAt,YYYY-MM-DD` | The date in a [Moment.js format](https://momentjs.com/docs/#/displaying/format/). The default is ISO 8601. `undefined` if the input isn't a date | | `slice` | `/#fn:slice,steps.1.tags,0,3` | Part of an array or string, like JavaScript's `slice(start, end)` | | `map` | `/#fn:map,steps.lookup.emails,email` | Pulls one property out of every item in an array: `["jane@example.com", …]` | | `transform` | `/#fn:transform,steps.call.body.items,name=title,sku=id` | Each array item reshaped: the new key `name` takes the old key `title`, and so on | | `cond` | `/#fn:cond,steps.1.status,open=Waiting,done=Resolved` | The value for the matching key, or `undefined`. Matches strings exactly, so it doesn't work on numbers | | `ifExists` | `/#fn:ifExists,steps.lookup.id,/#steps.lookup.name` | The second expression if the path has a value, otherwise `undefined`, so the param is left out | | `URIEncode` | `/#fn:URIEncode,steps.1.attributes.data.email` | `encodeURIComponent` of the value | | `URIDecode` | `/#fn:URIDecode,steps.1.attributes.data.redirect` | `decodeURIComponent` of the value | | `isValidEmailAddress` | `/#fn:isValidEmailAddress,steps.1.attributes.data.email` | `true` or `false` | | `isValidPhoneNumber` | `/#fn:isValidPhoneNumber,steps.1.attributes.data.phone` | `true` if the number can be formatted as a valid phone number | | `findIncludedResourceAttribute` | `/#fn:findIncludedResourceAttribute,steps.call.body.included,type=order,id=4417,attributes.total` | From a JSON:API `included` array, the property of the first resource matching every `key=value` | | `inBusinessHours` | `/#fn:inBusinessHours,steps.1.createdAt,64f1c0ffee5ca1ab1e0000aa` | Whether the date falls within a [business schedule](https://developer.kustomer.com/api/core-resources/create-a-business-schedule). See below | ### inBusinessHours | Form | Checks | | ------------------------------------------------ | ---------------------------------------------------------------------------- | | `/#fn:inBusinessHours,` | Now, against that schedule | | `/#fn:inBusinessHours,,` | The date at the path, against that schedule | | `/#fn:inBusinessHours,,` | The date, against the schedule ID found at a second path, such as a variable | | `/#fn:inBusinessHours,` | The date, against the org's default schedule | Holidays on the schedule count as closed. If there's no schedule to check against, or the date isn't valid, the result is `true`. ```json title="Route differently out of hours" { "target": "after-hours-reply", "condition": { "op": "neq", "values": ["/#fn:inBusinessHours,steps.1.createdAt,64f1c0ffee5ca1ab1e0000aa", true] } } ``` ## Handlebars helpers Use helpers inside templates, with positional arguments first and then `key=value` options. Wrap them in triple braces, `{{{ }}}`, so the output isn't HTML-escaped. Arguments can be paths (`steps.1.createdAt`), quoted strings or numbers. ### Dates | Helper | Example | Output | | --------------- | --------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------- | | `date` | `{{{date 'hours' count=24}}}` | ISO timestamp 24 hours **ago**. Units: `minutes`, `hours`, `days`, `years`, singular or plural | | `date` (future) | `{{{date 'days' count=-3}}}` | ISO timestamp 3 days **from now**. Use a negative count | | `dateFormat` | `{{{dateFormat steps.1.createdAt format='MMMM Do YYYY, h:mma' timezone='America/New_York'}}}` | `October 21st 2026, 11:20am` | | `dateDiff` | `{{{dateDiff 'hours' from=steps.1.createdAt to=steps.1.lastDone.createdAt}}}` | Whole units from `from` to `to`. Units: `years`, `quarters`, `months`, `weeks`, `days` (default), `hours`, `minutes`, `seconds`, `milliseconds` | `dateFormat` options: `format` (Moment.js, default `LL`, such as "October 21, 2026"), `locale` (default `en-us`), `inputTimezone` and `timezone` (output; IANA names or `UTC`). It accepts ISO strings and Unix timestamps in milliseconds, and outputs an empty string for invalid dates. > **Schedule for later with a negative count:** `date` counts backwards from now. `{{{date 'hours' count=24}}}` is 24 hours **ago**, which is a common mistake when scheduling. To compute an absolute `runAt` for the [Scheduler](https://developer.kustomer.com/docs/workflows/triggers-and-actions#schedule-a-workflow), use a negative count: `"value": "{{{date 'hours' count=-2}}}"` is two hours from now. For a fixed delay, a relative `runAt` in seconds is simpler. ### Signing and encoding | Helper | Example | Output | | -------------- | --------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------- | | `authHMAC` | `{{{authHMAC steps.1.id secretKey=variables.6513b2f4a4b1e1001a6b3f24 algorithm='sha256' encoding='hex'}}}` | HMAC of the first argument. `algorithm`: `sha1`, `sha224`, `sha256` (default), `sha384`, `sha512`. `encoding`: `base64` (default), `hex`, `utf8`, `ascii` | | `base64Encode` | `{{#base64Encode}}{{{variables.6513b2f4a4b1e1001a6b3f22}}}:{{{variables.6513b2f4a4b1e1001a6b3f23}}}{{/base64Encode}}` | Base64 of the block's content. Add `uriEncode="true"` to URL-encode the result | | `base64Decode` | `{{#base64Decode}}{{{steps.1.attributes.data.payload}}}{{/base64Decode}}` | Decoded block content (ASCII) | | `uriEncode` | `{{{uriEncode steps.1.attributes.data.email}}}` | `encodeURIComponent` | | `uriDecode` | `{{{uriDecode steps.1.attributes.data.next}}}` | `decodeURIComponent` | The long hex strings in these examples are [workflow variable](https://developer.kustomer.com/docs/workflows/conditions-and-expressions#variables-and-secrets) IDs. Workflows refer to variables by ID, never by name. See [Call your own code](https://developer.kustomer.com/docs/workflows/code-steps#sign-your-requests) for signing requests to your own services with `authHMAC`. ### JSON and text | Helper | Example | Output | | ---------------- | ---------------------------------------------------------------------------------------------- | ----------------------------------------------------- | | `toJSON` | `{{{toJSON steps.lookup.custom}}}` | The value as JSON text | | `parseJSON` | `{{#parseJSON steps.call.body}}{{{order.number}}}{{/parseJSON}}` | Renders the block with the parsed JSON as its context | | `split` | `{{{split steps.1.attributes.data.name separator=' ' index=0}}}` | One part of a split string | | `substring` | `{{{substring steps.1.preview start=0 end=140}}}` | Part of a string | | `replace` | `{{{replace steps.1.preview search='[0-9]{4}-[0-9]{4}-[0-9]{4}-[0-9]{4}' newvalue='[card]'}}}` | Regex replace. `flags` defaults to `gm` | | `markdownToHTML` | `{{markdownToHTML steps.note.body}}` | Inline HTML from Markdown | | `removeMarkdown` | `{{{removeMarkdown steps.1.preview}}}` | Plain text without Markdown syntax | | `formatCurrency` | `{{{formatCurrency steps.order.data.total currency='EUR' locale='de-DE'}}}` | `1.234,56 €`. Defaults: `USD`, `en-US` | | `math` | `{{{math steps.order.data.total '*' 100}}}` | `+`, `-`, `*`, `/` or `%` on two numbers | | `randomId` | `{{{randomId size=12}}}` | A random ID string. Pass the length as `size` | The string helpers from [Lodash](https://lodash.com/docs#camelCase) are available too, each taking one string: `camelCase`, `capitalize`, `escape`, `escapeRegExp`, `kebabCase`, `lowerCase`, `lowerFirst`, `snakeCase`, `startCase`, `toLower`, `toUpper`, `trim`, `trimEnd`, `trimStart`, `truncate`, `upperCase` and `upperFirst`. Conditions accept templates, so these helpers also make text checks case-insensitive: `{ "op": "contains", "values": ["{{{toLower steps.1.subject}}}", "refund"] }`. See [Case-insensitive text checks](https://developer.kustomer.com/docs/workflows/conditions-and-expressions#case-insensitive-text-checks). ### Logic | Helper | Example | Output | | --------- | -------------------------------------------------------------------- | ------------------------------------------------------------------------------------- | | `or` | `{{{or steps.lookup.firstName 'there'}}}` | The first value if it's truthy, otherwise the second | | `cond` | `{{{cond steps.1.status open='Waiting on us' done='Resolved'}}}` | The option named by the value, or an empty string | | `ifCond` | `{{#ifCond steps.1.priority '>=' 4}}Urgent{{else}}Normal{{/ifCond}}` | Block helper. Operators: `==`, `===`, `!=`, `!==`, `<`, `<=`, `>`, `>=`, `&&`, `\|\|` | | `isEmpty` | `{{#isEmpty steps.1.tags}}Untagged{{else}}Tagged{{/isEmpty}}` | Block helper: empty strings, arrays, objects, `null` and `undefined` are empty | Handlebars' built-ins (`if`, `unless`, `each`, `with`, `lookup`) work as documented at [handlebarsjs.com](https://handlebarsjs.com/guide/builtin-helpers.html). ### App settings In workflows that ship with an [app](https://developer.kustomer.com/docs/apps/settings), `{{{ setting .. }}}` inserts the installing org's value for that setting. Write it with exactly one space inside each set of braces, as shown. To supply a fallback and a type, add them after the path: `{{{ setting .. }}}`. Settings are resolved before the rest of the template renders, and invalid `setting` references are rejected when you save the workflow. ## Criteria Queue rules and satisfaction surveys don't use workflow conditions. They use **criteria**: an object with `and` and `or` lists of field checks. ```json title="Route VIP chats to a queue" { "and": [ { "conversation_channel": { "operator": "in", "value": ["chat"] } }, { "customer_custom_tierStr": { "operator": "equals", "value": "gold" } } ], "or": [ { "conversation_priority": { "operator": "gte", "value": 4 } }, { "conversation_preview": { "operator": "contains_any_of", "value": ["refund", "chargeback"] } } ] } ``` The criteria match when **every** `and` check passes **and** at least one `or` check passes. An empty list doesn't restrict anything, so `{ "and": [], "or": [] }` matches everything. | Where | Endpoint | | ------------------------- | ---------------------------------------------------------------------------------------------------------------------- | | Queue rules | [`POST /v1/routing/queue-rules`](https://developer.kustomer.com/api/queues-and-routing/create-queue-rule) | | Fields queue rules accept | [`GET /v1/routing/queue-rules-criteria`](https://developer.kustomer.com/api/queues-and-routing/get-queue-criteria) | | Satisfaction surveys | [`POST /v1/satisfaction`](https://developer.kustomer.com/api/settings-and-configurations/create-a-satisfaction-survey) | ### Field names A field is `_`, where the object is `conversation`, `customer`, `message`, `company` or `kobject`, and the attribute keeps its camelCase name: `customer_lastSeenAt`, `conversation_assignedTeams`. Custom attributes are `_custom_`, such as `conversation_custom_orderNumberStr`. A few names are shortcuts: `conversation_channel` checks `channels`, and `customer_email` and `customer_phone` check the primary email and phone. The queue rules criteria endpoint lists every field you can use, with its type and an `operator` group (`string`, `number`, `datetime`, `boolean`, `list`) that tells you which operators make sense. > **Not the same as search:** Criteria field names look like [search](https://developer.kustomer.com/docs/concepts/search) attribute names but aren't the same. Search uses names such as `customer_last_seen_at`, while criteria use the attribute's camelCase name. Don't copy one into the other. ### Operators | Operator | `value` | Passes when | | ------------------------ | ----------------- | ------------------------------------------------------------------------------------------------------------------------------- | | `is_set` | none | The field has a value. `false` and `0` count as set; empty strings and empty arrays don't | | `not_set` | none | The field is missing, `null`, an empty string or an empty array | | `equals` | any | Equal after casting the value to the field's type. For an array field, the array includes the value | | `not_equals` | any | `equals` would fail | | `gt`, `gte`, `lt`, `lte` | number or date | Numeric comparison, or a date comparison if the value is a date. See relative dates below | | `in` | array | The field's value is in the list. For an array field, at least one item is | | `not_in` | array | `in` would fail | | `contains` | string or array | The field contains the text, ignoring case. For an array field, an item does. With an array value, every item must be contained | | `not_contains` | string or array | `contains` would fail | | `contains_any_of` | array | The field contains at least one of the strings, ignoring case | | `not_contains_any_of` | array | It contains none of them | | `matches` | regex string | The field matches the regular expression (case-sensitive) | | `in_business_hours` | schedule ID | The date field falls within the business schedule | | `not_in_business_hours` | schedule ID | It doesn't | | `changes` | `before`, `after` | The field changed in this update, and its old and new values match the nested checks | Date comparisons accept ISO 8601 timestamps or relative values: `now-2d` means two days ago and `now+1h` an hour from now. The units are `s` (seconds), `m` (minutes), `h` (hours), `d` (days), `w` (weeks) and `M` (months), with up to 99 of each. ```json title="Last seen more than a week ago" { "customer_lastSeenAt": { "operator": "lt", "value": "now-7d" } } ``` ```json title="Status changed from open to done" { "conversation_status": { "operator": "changes", "before": { "operator": "equals", "value": "open" }, "after": { "operator": "equals", "value": "done" } } } ``` A check on a custom attribute that has since been deleted is ignored, so it passes. Remove such checks when you delete attributes.