I am writing a software documentation and I need a antonym to "legacy code". Is there any established word for the antonym to "legacy code"? I'll need this antonym to describe that code which was written by myself.

Example: The main focus is to replace legacy code by [antonym] code.

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    I think that the term for the code you are writing today is tomorrow's legacy code. Apr 27, 2017 at 7:25
  • Is your documentation for software which contains legacy code and your new written code?
    – IQV
    Apr 27, 2017 at 7:29
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    "code with tests". Mike Feathers defines "legacy ode" as "code without tests", hence the antonym is "code with tests". Sadly, most developers write "legacy code" even in "green field" projects. Apr 27, 2017 at 7:47
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    I think "new code" is all you need. Apr 27, 2017 at 12:06
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    @Walfrat: sure, but to my understanding "refactoring" means applying code transformations like the ones given by Fowler in his catalog. Throwing away even a single function and reimplementing it from scratch, even if the function has less than 10 lines and has the same signature than the old one, is not in that list.
    – Doc Brown
    Apr 27, 2017 at 12:06

4 Answers 4



A greenfield project is a project without any requirement of compatibility with legacy systems. The allusion is to a field of green grass on which nothing has been built.

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    In such cases though, legacy projects are referred to as "brownfield" and not "legacy".
    – Sklivvz
    Apr 27, 2017 at 7:58
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    In OP case I diasagree The main focus is to replace legacy code by [antonym] code. There are already existing code, so this answer is not the right.
    – Walfrat
    Apr 27, 2017 at 11:37
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    If the person is dealing with a system that contains legacy code, the replacement won't be "greenfield" since it still has to interface with other pre-existing code and infrastructure. The OP didn't give the impression that they are rewriting the entire code base. Apr 27, 2017 at 12:08

Going by your example sentence, I assume that you use legacy code in the sense of code that cannot be understood, maintained, or improved with reasonable effort, i.e., you hope that the code you wrote is not future legacy code. Therefore I suggest sustainable as the antonym, as it emphasises that future developers can use your code.

The main focus is to replace legacy code by sustainable code.


That would be just code or new code. Note that the term "legacy" in IT implies it is no longer considered optimal. Stuff you are not happy with yet still cannot do without. It may originally have been introduced as a respectful term or eufemism but its connotation today is rather negative.

A true antonym would imply you have no issues with the code regarding its applicability or usefulness to today's environment. You could call it modern code.

I would rather avoid qualifications like these at all though and stick to the technical qualifications instead that do not bear the old/bad versus new/good feel.

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    Or as I like to call it, "Legacy-code-in-waiting" or "Tomorrow's Legacy Code" Apr 27, 2017 at 12:44

In your example you can use "novel code".

Keep in mind that "legacy" is mostly a relative comparison between two bits of code, meaning "older than something" as there is no strict point at which code becomes "legacy". So a word like "novel", while not strictly in use for this, might be appropriate to strike the difference in reverse.

legacy: adj
of or relating to old or outdated computer hardware, software, or data that, while still functional, does not work well with up-to-date systems.

novel: adj
of a new kind; different from anything seen or known before.

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    I don't think "novel" is the right word here. It may not be "different from anything seen or known before", it may be just ordinary code, or code that is simply best-practice code to replace poorly written code. It won't be a new "kind" of code, just new code. Apr 27, 2017 at 12:10
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    @Bryan It is not about bad code versus good code, it is about code from the past versus code from the current era. From a linguistic point of view one could state that current is not an antonym to past, that it should imply future. Or at least "as new as it gets", the other end of the spectrum rather than the middle. So I do not think this is a bad answer at all. Apr 27, 2017 at 13:37
  • " It is not about bad code versus good code, it is about code from the past versus code from the current era" - I agree. "code from the current era" or even "code from the future" is not necessarily novel. "novel" is not a synonym for "new". It's closer in meaning to "unique" or "ground-breaking". If I replace a = a + 1 with a += 1, that's not novel because there are millions of lines of code that do similar things. Apr 27, 2017 at 14:52
  • @BryanOakley a+1 is a bad example, because it would not be legacy either, in itself. I would call the codebase novel, because it's a novel solution within the company, exactly unlike the previous legacy solution.
    – Sklivvz
    Apr 27, 2017 at 17:22

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