# String filters
> Filters for changing and encoding text.
These filters change and encode text. Apply a filter with `|`, as in `{{ title|upper }}`. Lengths and positions count Unicode code points, not JavaScript's UTF-16 units. A letter written with a separate accent mark, or an emoji made of several code points, counts as more than one.
Most string filters return an empty string for null, so optional fields print nothing.
## Safe markup
Given safe markup, such as the content of [`apply`](https://kilnlang.com/docs/tags/apply/) or a value marked with `raw`, these filters return safe markup too: `upper`, `lower`, `capitalize`, `title`, `trim`, `replace`, `truncate`, `stripTags` and `nl2br`. They change only the text. Tags and entities stay as they are, and any text they add, such as a replacement, is escaped. Other filters return plain values, which are escaped when printed.
page.kiln:
```kiln
{{ html|raw|upper }}
```
Output:
```html
ABOUT & CONTACT
```
## `upper` and `lower`
Change text to upper or lower case.
page.kiln:
```kiln
{{ "Hello"|upper }} {{ "Hello"|lower }}
```
Output:
```html
HELLO hello
```
## `capitalize`
Makes the first character upper case and the rest lower case.
page.kiln:
```kiln
{{ "hELLO wORLD"|capitalize }}
```
Output:
```html
Hello world
```
## `title`
Starts each word with an upper-case letter and makes the rest lower case. Accent marks and apostrophes belong to the word they are in, so "o'neil" becomes "O'neil".
page.kiln:
```kiln
{{ "the QUICK brown fox"|title }}
```
Output:
```html
The Quick Brown Fox
```
## `trim`
Removes whitespace from both ends. Pass characters to remove instead, and `"start"` or `"end"` to trim one side.
page.kiln:
```kiln
{{ " hello "|trim }}|{{ "--hello--"|trim("-", "end") }}
```
Output:
```html
hello|--hello
```
## `replace`
Replaces every match of a piece of text. Pass a hash to replace several at once, and the longest match wins at each position. It matches plain text, not regular expressions.
page.kiln:
```kiln
{{ "I like tea"|replace("tea", "coffee") }}
{{ "Hi NAME, welcome to PLACE"|replace({ NAME: "Ada", PLACE: "Kiln" }) }}
```
Output:
```html
I like coffee
Hi Ada, welcome to Kiln
```
## `split`
Splits text into an array. An optional limit caps the number of items. An empty separator splits into characters.
page.kiln:
```kiln
{{ "a,b,c"|split(",")|join(" / ") }}
{{ "a,b,c"|split(",", 2)|join(" / ") }}
```
Output:
```html
a / b / c
a / b
```
## `truncate`
Shortens text to a length, trims trailing spaces and adds an ellipsis if it cut anything. Pass a different ending as the second argument. Given safe markup, it counts only the text and closes any tags the cut leaves open.
page.kiln:
```kiln
{{ "Kiln is a template language"|truncate(13) }}
{{ "Short"|truncate(13) }}
```
Output:
```html
Kiln is a tem…
Short
```
## `stripTags`
Removes HTML tags and comments. It doesn't decode entities such as `&`, and removing a tag never leaves a new one behind. Its result is still escaped, so don't mark it with `raw` to make it safe.
page.kiln:
```kiln
{{ "Hello world
"|stripTags }}
```
Output:
```html
Hello world
```
## `nl2br`
Escapes the text, then adds a `
` before each line break. Safe markup isn't escaped again. The result is safe HTML.
page.kiln:
```kiln
{{ "Line one
Line two"|nl2br }}
```
Output:
```html
Line one
Line two
```
## `urlEncode`
Encodes a string for use in a URL, or turns a hash into a query string.
page.kiln:
```kiln
/search?q={{ "tea & cake"|urlEncode }}
/search?{{ { q: "tea", page: 2 }|urlEncode }}
```
Output:
```html
/search?q=tea%20%26%20cake
/search?q=tea&page=2
```
## `json`
Turns a value into JSON. Pass a number to indent it. Sets, generators and other iterables become arrays. The output escapes `<`, `>` and `&`, so it is safe inside a `
```
Output:
```html
```
## `escape`
Escapes a value with a strategy: `"html"` (the default), `"attr"`, `"js"`, `"css"` or `"url"`. See [Escaping](https://kilnlang.com/docs/language/escaping/).
page.kiln:
```kiln
Tag
```
Output:
```html
Tag
```
## `raw`
Marks a value as safe, so it is output without escaping. Only use it for HTML you trust. Put it after filters that return plain values, such as `split` and `join`.
page.kiln:
```kiln
{{ html|raw }}
```
Output:
```html
Trusted
```