What is the difference between Helm functions and Sprig functions?

Sprig is the upstream Go template function library that supplies most string, list, math and encoding helpers. Helm adds a handful of chart-specific functions on top, such as include, tpl, required, lookup and the Files object, which are not part of Sprig.

How do I render a value as a quoted YAML string?

Pipe it through quote, for example {{ .Values.name | quote }} produces a double-quoted string. Use squote for single quotes. Always quote user-supplied strings so values that look like numbers or booleans are not misinterpreted by the YAML parser.

When should I use include instead of template?

include returns the rendered output as a string so you can pipe it into functions like indent or nindent, which template cannot do because it writes directly to output. Prefer include for any named template whose result needs further processing.

What does the required function do?

required "message" .Value fails the render with the given error message if the value is empty or nil, otherwise it returns the value. It is the standard way to enforce that a chart user has supplied a mandatory configuration value.

Why use nindent instead of indent?

nindent prepends a newline before indenting every line by the given number of spaces, which is convenient when embedding a multi-line block after a YAML key. indent only adds spaces without the leading newline, so you often combine it with a manual newline.

Helm Template Functions Reference

Helm template functions reference

Helm charts are Go templates rendered with the Sprig function library plus a few Helm-specific helpers. Knowing the exact function name, signature, and pipeline behavior is what separates a clean chart from one full of YAML indentation bugs. This reference lists the most-used functions grouped by category, each with its signature and a worked example.

Filter by name or category below, and try a couple of common functions live in the playground at the bottom.

How it works

Templates evaluate left to right, and the pipe operator | feeds the previous result as the last argument of the next function — so {{ .Values.x | default "y" | quote }} reads naturally. Functions fall into families: string (upper, trim, replace, printf), flow/defaults (default, required, ternary, coalesce), lists (first, last, append, uniq), dicts (get, set, hasKey, keys), math (add, mul, max), encoding (b64enc, toJson, toYaml), and Helm-only (include, tpl, required, lookup).

Indentation helpers matter most: indent N adds N spaces to every line; nindent N adds a leading newline first. They are almost always paired with include (which returns a string) rather than template (which writes to output and cannot be piped). tpl re-renders a string as a template against the current context, useful for values that themselves contain template syntax.

Tips and examples

Common patterns from real charts:

name: {{ .Values.name | default .Chart.Name | quote }}
data:
  config.yaml: |
{{ toYaml .Values.config | indent 4 }}
labels:
  {{- include "mychart.labels" . | nindent 2 }}
secret: {{ required "secretKey is required" .Values.secretKey | b64enc }}

Always quote strings, use nindent when embedding a block under a key, and reach for include over template whenever the result needs piping. The interactive playground lets you try upper, quote, default, b64enc, and repeat on your own input.

Helm Template Functions Reference

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Helm template functions reference

How it works

Tips and examples