Source code management (SCM) is the practice and tooling for tracking and managing changes to source code over time. Its core capability is version control: keeping a recorded history of revisions so that people can see what changed, compare versions, and recover an earlier state. In everyday engineering usage, the term also stretches to cover the collaboration workflows built around that history, such as proposing, reviewing and integrating changes.
What source code management covers
SCM is a category of practice and tools, not a single product. A team that uses SCM gives its source code a recorded past, so any change can be inspected, any earlier state can be restored, and the people working on a project can see who changed what and when. The same idea applies whether the project is a single script or a large application maintained by many contributors.
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The most useful way to hold the definition is to separate the core function from the surrounding practice. The core function is revision tracking. The surrounding practice includes review, approval and integration of changes. Both are commonly called SCM, but they are not the same thing, and the sources that define the term do not agree on exactly where the boundary falls.
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Version control: the core of SCM
Version control is the mechanism that does the tracking. The Pro Git book, published by the Git project, defines it this way: “Version control is a system that records changes to a file or set of files over time so that you can recall specific versions later.” Pro Git, 2nd Edition, “About Version Control”
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In practice, that record lets a developer answer questions such as which version of a file introduced a bug, what a function looked like before a refactoring, or whether a particular file has changed since a release. Recovery is one of the main reasons teams adopt it: an earlier state can be retrieved rather than rebuilt from memory.
Two meanings of “SCM”
Narrow usage: SCM as another name for version control
In its narrow sense, SCM and source control or version control refer to the same thing: the system that stores and tracks the history of source files. Documentation from the Git project describes Git at this level of the stack, as software that manages revisions. Git User Manual
Broad usage: SCM as the surrounding workflow
In its broader sense, SCM also includes the processes around the history: proposing a change, having it reviewed, deciding whether it can be integrated, and governing who may do each step. Atlassian and GitLab both describe SCM in these wider terms, covering the tools and practices teams use to manage code changes across their life cycle. Atlassian, “Source Code Management” GitLab, “What is source code management (SCM)?”
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When you read the term in a job posting, a tool comparison or a team wiki, check which sense is meant. A statement such as “we use SCM” may mean only that the code is versioned, or it may mean that the review and approval process is also defined.
Repositories and history
A repository is the unit that version control works on. GitHub Docs describes a repository, or Git project, as encompassing a project’s files and folders along with each file’s revision history. GitHub Docs, “About Git” The history is part of the repository, not a separate log kept somewhere else, which is why copying or synchronizing a repository carries its past with it.
A repository is not necessarily tied to a website. A Git repository can be a complete local unit on a developer’s machine, and it remains usable there without any connection to a hosting service. Microsoft Learn, “What is Git?”
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Git and GitHub are different things
Git is version-control software. It is a distributed revision control system, as the Git User Manual puts it: “Git is a fast distributed revision control system.” Git User Manual
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GitHub is a hosting and collaboration platform for Git projects. It is one service that stores Git repositories and adds collaboration features around them. Other hosting services exist, and using GitHub is not required to use Git. Naming Git when you mean GitHub, or the reverse, leads to confusion about where a project’s history actually lives. GitHub Docs, “About Git”
Centralized and distributed version control
Version-control systems differ mainly in where the working history is stored. The difference shapes daily work, not only architecture.
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In a centralized system, a central server holds the versioned files, and clients check out work from that central location. The shared hub and administrative control are easy to see, but the server becomes an availability concern, and the data is only as safe as the server’s backups. Pro Git, 2nd Edition
In a distributed system such as Git, each clone contains the repository history and supports local work. Contributors synchronize repositories when they share changes. Pro Git, 2nd Edition Microsoft Learn, “What is Git?”
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|---|---|---|
| Where the versioned history lives | On a central server that clients check out from | In each clone, which holds the full repository history |
| Can local work continue without the shared server? | Depends on server connectivity, per the central checkout model | Yes, a clone supports local work on its own history |
| How changes are shared | Through the central location | By synchronizing repositories with another repository |
| Main operational concern | Server availability, and backups for data loss | Keeping clones synchronized; repository size on each machine |
| Permission and access management | Not stated in these sources | Not stated in these sources |
Repository size is named in the sources as an operational consideration, but none of them quantify it, so treat it as a planning question for your own project rather than a fixed limit.
How to compare the two models
When you evaluate a system, use four questions:
- Where does the authoritative or shared history reside?
- Does local work depend on a server connection?
- How are collaboration and permissions managed?
- What happens to the team when the server is unavailable, when backups are inadequate, or when repositories grow large?
Neither model is universally better. The right choice depends on how a team works, how reliably it can operate shared infrastructure, and how often its members work offline or across unstable connections.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.What SCM does not guarantee
- SCM does not make a project a single product. It is a practice and a category of tools, and different tools implement it differently.
- Version control records changes; it does not by itself prevent conflicting edits. Conflicts are handled through the workflow a team adopts.
- The sources describe what these systems can do, not what will happen under every configuration. A repository can only be restored if its history was actually retained and is accessible, which depends on how it is hosted and backed up.
Keeping these distinctions clear is what turns the definition into something you can use: SCM is the discipline of recording and managing code changes, version control is the mechanism that records them, and Git and GitHub are specific tools within that category.
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