Why are tags considered immutable?

Tags in Git are considered immutable because they must always point to the same state of the code and serve as a reliable fixed point for a version or a release.

In simpler terms: a tag is a "fixed version", not a working pointer.

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#What "immutable" means in practice

When people say a tag is immutable, they mean:

• a tag should not "move" to another commit
• the tag's value does not change over time
• v1.2.0 always points to the same commit

This rule is a convention, not a strict technical restriction.

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#Technically: can a tag be changed?

Yes, technically it can:

• delete the tag
• recreate it with the same name but on a different commit

But this: breaks history confuses CI/CD makes releases untrustworthy

That is why it is considered bad practice.

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#Why this matters for versions and releases

#1. Reliability of versions

If a tag changes:

• the v1.0.0 version today and tomorrow may mean different code
• it becomes impossible to reproduce a bug or a build

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#2. Stability of CI/CD

Very often:

• deployment to production is triggered by a tag
• the tag equals the version

If the tag moved:

• you could deploy different code under the same version number

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#3. Audit and rollbacks

• a tag makes it easy to find what was shipped
• you can go back to an older version
• history stays honest

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#4. Difference from branches

• a branch is a "live pointer"
• a tag is a historical marker

Changing historical markers is a bad idea.

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#Phrasing for an interview

Tags are considered immutable because they fix a specific version or release and must always point to the same state of the code. Changing a tag breaks reproducibility and automation.