2026.10.4
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Convert to slug format: slugify

The slugify template function converts a string into a slug format, which is a URL-friendly, lowercase version of the text with special characters removed and spaces replaced by a separator. By default it uses underscores as the separator, but you can choose any character you like, such as a hyphen.

Slugs are the format Home Assistant uses for entityAn entity represents a sensor, actor, or function in Home Assistant. Entities are used to monitor physical properties or to control other entities. An entity is usually part of a device or a service. [Learn more] IDs, so this function is handy whenever you need to build or match entity IDs dynamically. For example, you might want to turn a room name from a sensor into an entity ID format, or create consistent naming for use in automationsAutomations in Home Assistant allow you to automatically respond to things that happen in and around your home. [Learn more] and scriptsA script is a saved list of steps that runs when you start it, for example, from a dashboard, with Assist, or from an automation. Unlike an automation, a script has no triggers, so it doesn’t start by itself. [Learn more]. It is also useful when generating filenames or identifiers that should not contain spaces or special characters.

Usage

Here’s how to use this template function. Copy any example and adjust it to your setup.

TemplateA template is an automation definition that can include variables for the action or data from the trigger values. This allows automations to generate dynamic actions. [Learn more] 
{{ slugify("Hello World!") }}
Result (stringA piece of text, like a name, message, or entity ID. In templates, wrap strings in quotes, like "living_room" or "lights are on".) 
hello_world

Function signature

The signature is a technical summary of this template function. It shows the name of the function, the values (called parameters) it accepts, and what type of data each parameter expects (for example, a piece of text or a number).

Function parameters that have a = with a value after them are optional. If you leave them out, the default value shown is used automatically.

Function parameters without a = are usually required. A few optional parameters have no default value, so the signature shows them without a = as well. To check whether a parameter is required, look at the parameter list below the signature. Each parameter is marked as Required or Optional.

The most common optional parameter without a default value is default. The default parameter sets the value a function returns when the function can’t produce a result, for example, when float gets text that isn’t a number. If you leave out default, there is no fallback value, so most functions raise an error and the template fails. The parameter list of each function says what happens. If you set default, the function returns your value instead.

How to read a signature

Here is the signature of the round filter as an example:

round(
    value: Any,
    precision: int = 0,
    method: str = "common",
    default: Any,
) -> float | int | Any
  • round is the name of the function.
  • Between the parentheses are the parameters. Each parameter has a name, followed by a colon and the type of value the parameter expects. The type only tells you what kind of value to pass. For default: Any, you pass a value of any type, such as 0 or "unknown", not the word Any.
  • = 0 and = "common" are default values. You can leave out precision and method, and round uses these default values.
  • default has no =, but the parameter list marks default as optional. If you leave out default and round gets a value that isn’t a number, round raises an error.
  • -> shows the type of value the function returns.
  • Inside a signature, | means “or”. This function returns a decimal number, a whole number, or the value you passed as default.

round is a filter, so the first parameter, value, is the value before the |. For example, {{ 3.14159 | round(2) }} returns 3.14.

The types you’ll see most often:

  • str: text, such as "hello"
  • int: a whole number, such as 5
  • float: a decimal number, such as 3.14
  • bool: true or false
  • list: a list of values, such as [1, 2, 3]. list[str] is a list of texts.
  • dict: a set of keys and values, such as {"name": "Kitchen"}
  • datetime and timedelta: a date and time, and a duration. For details, refer to Dates and times.
  • None: no value
  • Any: any type of value

Some signatures use special forms:

  • *args means you can pass any number of values, separated by commas. For example, average(1, 2, 3).
  • value | name(...) means the function is a filter. The value before the | is passed to the filter as its first parameter. Some filter signatures, like the round example, show this value as the first parameter between the parentheses instead.
slugify(
    value: str,
    separator: str = "_",
) -> str

Function parameters

The following parameters can be provided to this function.

value string Required

The string to convert into a slug. Special characters are removed, spaces are replaced by the separator, and the result is lowercased.

separator string (Optional, default: “_”)

The character to use between words. Defaults to an underscore (_).

Using a custom separator

You can use a hyphen or any other character as the separator instead of the default underscore.

TemplateA template is an automation definition that can include variables for the action or data from the trigger values. This allows automations to generate dynamic actions. [Learn more]: Using a hyphen separator 
{{ slugify("Living Room Light", "-") }}
Result (stringA piece of text, like a name, message, or entity ID. In templates, wrap strings in quotes, like "living_room" or "lights are on".) 
living-room-light

Good to know

  • The default separator is an underscore, which matches the Home Assistant entity ID format.
  • The result is always lowercase, regardless of the input case.
  • Accented characters are stripped to plain ASCII equivalents where possible.

Try it yourself

Ready to test this? Open Settings > Tools > Template, paste the example into the Template editor, and watch the result update on the right. Edit the values to see how the function adapts to your own entitiesAn entity represents a sensor, actor, or function in Home Assistant. Entities are used to monitor physical properties or to control other entities. An entity is usually part of a device or a service. [Learn more].

More examples

Real scenarios where this function comes up in automations and templates. Copy any example and adapt it to your setup.

Build an entity ID from a room name

Turn a human-readable room name into an entity ID format that can be used to look up entitiesAn entity represents a sensor, actor, or function in Home Assistant. Entities are used to monitor physical properties or to control other entities. An entity is usually part of a device or a service. [Learn more].

TemplateA template is an automation definition that can include variables for the action or data from the trigger values. This allows automations to generate dynamic actions. [Learn more] 
{{ "light." ~ slugify("Kitchen Ceiling") }}
Result (stringA piece of text, like a name, message, or entity ID. In templates, wrap strings in quotes, like "living_room" or "lights are on".) 
light.kitchen_ceiling

Create a consistent identifier from user input

When processing input from a text helper or other source, convert it to a clean slug for use in templates.

TemplateA template is an automation definition that can include variables for the action or data from the trigger values. This allows automations to generate dynamic actions. [Learn more] 
{% set room = states("input_text.room_name") %}
sensor.temperature_{{ slugify(room) }}
Result (stringA piece of text, like a name, message, or entity ID. In templates, wrap strings in quotes, like "living_room" or "lights are on".) 
sensor.temperature_living_room

Still stuck?

The Home Assistant community is quick to help: join Discord for real-time chat, post on the community forum with your template and expected result, or share on our subreddit /r/homeassistant.

Tip

AI assistants like ChatGPT or Claude can also explain or fix templates when you describe what you want in plain language.

Related template functions

These functions work well alongside this one: