Pattern

Regex for Kubernetes resource name

DNS-1123 label — lowercase alphanumeric and hyphens.

The Kubernetes resource name regex is ^[a-z0-9]([-a-z0-9]*[a-z0-9])?$ — copy it below, or open it in the explainer for a token-by-token breakdown.

The pattern

^[a-z0-9]([-a-z0-9]*[a-z0-9])?$

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What it matches

my-pod
app1
redis-master-0
a

What it doesn't match

MyPod
-leading
trailing-
my_pod

Notes & gotchas

Kubernetes object names follow RFC 1123 DNS labels: 1-63 chars, lowercase a-z, digits, hyphens; can't start or end with hyphen. Used for pods, services, deployments, etc.

Code in your language

Use the explainer's Code tab to generate ready-to-paste snippets in JavaScript, Python, Java, .NET, Go, Ruby, and PHP for this pattern.

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Token-by-token breakdown

Every part of the pattern, left to right:

Token	Meaning
`^`	start of string (or line in multiline mode)
`[a-z0-9]`	any of: lowercase letters, digits
`(`	start of a capturing group
`[-a-z0-9]*`	zero or more: any of: “-”, lowercase letters, digits
`[a-z0-9]`	any of: lowercase letters, digits
`)?`	end of group, optional (zero or one)
`$`	end of string (or line in multiline mode)

About this pattern

Developer-oriented patterns help with code analysis, log parsing, and data transformation. Use these in build scripts, CI tools, IDE search-and-replace, and code review utilities.

Quick usage in different languages

This exact pattern — with the correct escaping and idioms for each language:

JavaScript: /^[a-z0-9]([-a-z0-9]*[a-z0-9])?$/.test(value)
Python: re.match(r"^[a-z0-9]([-a-z0-9]*[a-z0-9])?$", value)
Java: Pattern.compile("^[a-z0-9]([-a-z0-9]*[a-z0-9])?$").matcher(value).matches()
C# / .NET: Regex.IsMatch(value, @"^[a-z0-9]([-a-z0-9]*[a-z0-9])?$")
Go: regexp.MustCompile(`^[a-z0-9]([-a-z0-9]*[a-z0-9])?$`).MatchString(value)
Ruby: /^[a-z0-9]([-a-z0-9]*[a-z0-9])?$/.match?(value)
PHP: preg_match('~^[a-z0-9]([-a-z0-9]*[a-z0-9])?$~', $value)

The explainer’s Code tab regenerates these for any pattern you paste, and the downloadable cheat sheet bundles the breakdown, all seven snippets, and the pitfalls below onto one printable page.

Common pitfalls

Anchored to the whole string. This pattern uses ^ and $, so it requires the entire input to match. To find it inside a longer text, drop the anchors and use the global (g) flag.
Lowercase only. Ranges like [a-z] won't match uppercase. Add A-Z (or the i flag) if uppercase input should be accepted.
Validate beyond format. Matching the format doesn't guarantee the value is real. Confirm the kubernetes resource name against a source of truth (database, API, or checksum) where it matters.

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