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Code quality

What is dead code detection?

Identifying code that is never reached or referenced, such as unused functions, unreachable branches and orphaned files.

By Cláudia FernandesUpdated

Dead code costs review time, slows builds and misleads anyone reading the codebase. It accumulates naturally as features are removed and refactors leave remnants behind.

Accurate detection is harder than it sounds in dynamic languages, where reflection, dependency injection and string-based dispatch can reference code in ways static analysis cannot see. Expect to verify before deleting.

What to look for

  • How the tool handles reflection and dynamic invocation
  • Whether public API surface is excluded from dead-code reporting
  • Confidence levels on findings rather than a flat list
  • Support for excluding entry points and framework-called methods

Best 6 dead code detection tools

Every tool in the directory whose documentation covers this, 5 fully and 1 partially. Full support is shown first. Shown in a random order that changes on every visit, so no tool gets an advantage from its position.

Support is not the same as parity, since some implementations are narrower in scope, gated to a higher plan tier, or maintained only for existing customers. The note under each tool is what its own documentation describes.

Code Quality Platform

Codacy
Team

Dedicated unused-code issue category; deadcode and aligncheck analyzers.

Free plan available

Code Security Platform

Corgea
Growth

Empty blocks, unused code, unreachable statements (CWE-563, CWE-1041)

Free plan available

Code Quality Platform

DeepSource

Dead code and unused imports raised under the anti-pattern category and the Hygiene dimension.

Free plan available

Code Quality Platform

Qlty
Free (CLI)

dead_code issue category; Knip plugin for unused JavaScript and TypeScript code

Free plan available

Code Security Platform

Snyk

Snyk Code coding-issue detection explicitly includes dead code and predefined branches.

Free plan available

Code Security Platform

Checkmarx OnePartial

Enabling Exploitable Path surfaces genuinely unused dependencies; dead source-code detection not documented.

Quote-based pricing
Code Smell DetectionComplexity MetricsDuplication DetectionTest Coverage TrackingDiff Coverage (New Code)Architecture Governance

FAQ

What is dead code detection?

Identifying code that is never reached or referenced, such as unused functions, unreachable branches and orphaned files.

How many tools in the directory offer dead code detection?

6 of the 20 tools in this directory offer dead code detection, 5 fully and 1 partially:

Checkmarx OneCodacyCorgeaDeepSourceQltySnyk

Support is not the same as parity, since some implementations are narrower in scope, gated to a higher plan tier, or maintained only for existing customers. The note under each tool is what its own documentation describes.

What should you check when comparing tools with dead code detection?

Four things:

  • How the tool handles reflection and dynamic invocation
  • Whether public API surface is excluded from dead-code reporting
  • Confidence levels on findings rather than a flat list
  • Support for excluding entry points and framework-called methods