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Software Engineering vocabulary · Release and Maintenance

Legacy code

Meaning in software engineering, with examples

/ˈleɡəsi koʊd/nounCommon term

In software engineering, legacy code means: Old code that is still in use, often written by people who have left, with little documentation or few tests, so it feels risky to change.

In Turkish: eski kod, miras kod, eski sistem kodu

How it is used

Developers maintain, modernize, migrate and sometimes fear legacy code. 'Legacy system' and 'legacy app' are common too. The word can be neutral or slightly negative, depending on the tone.

Example sentences

  1. Nobody wants to touch the legacy code in the billing module because it has no tests.

  2. Our plan is to wrap the legacy code in an API and replace it piece by piece.

Common collocations

  • maintain legacy code
  • legacy system
  • legacy codebase
  • migrate legacy code
  • technical debtThe future cost of shortcuts taken in code today: quick solutions that save time now but make later changes slower and riskier.
  • refactorTo improve the structure of existing code, making it cleaner or easier to change, without changing what it does for the user.
  • codebaseAll the source code that makes up a project or product, seen as one whole, including its structure, style and history.
  • documentationWritten material that explains how software works and how to use, set up or change it, such as guides, API references and README files.
  • deprecateTo officially mark a feature, function or API as outdated and not recommended, usually as a warning that it will be removed in a later version.

More terms: Release and Maintenance

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