Analysis & detection

What is Dead / Unused Code?

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

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.

Top 6 Dead / Unused Code tools

Every tool in the directory documented as supporting Dead / Unused Code, 5 fully, 1 partially, with what its own documentation says.

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.

  1. 1
    CodacyQuality PlatformTeam

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

  2. 2
    CorgeaCode Security PlatformGrowth

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

  3. 3
    DeepSourceQuality Platform

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

  4. 4
    QltyQuality PlatformFree (CLI)

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

  5. 5
    SnykCode Security Platform

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

  6. 6
    Checkmarx OneCode Security PlatformPartial

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

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

Related terms

SASTTaint / Data-Flow AnalysisSecrets DetectionSecrets ValidationSCA (Software Composition Analysis)Reachability Analysis

FAQ

What is Dead / Unused Code?

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

How many tools support Dead / Unused Code?

6 of the 20 tools tracked in this directory support Dead / Unused Code, 5 fully and 1 partially, including Codacy, Corgea, DeepSource, Qlty, Snyk. 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 look for in Dead / Unused Code?

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.