What Obfuscar is
Obfuscar is an actively maintained open-source renaming obfuscator distributed as a NuGet package and MSBuild task. Its scope is deliberately narrow: symbol renaming, done reliably.
This is the closest comparison on renaming, which both do free. On Pro we add string encryption, control-flow obfuscation, reference proxying and method virtualization on top; Obfuscar stays renaming-only.
The difference is entirely workflow. Obfuscar runs locally as part of your build, configured through an XML file you write and maintain. We run server-side with no configuration at all.
Obfuscar pricing
Obfuscar: Free and open source (MIT).
FreeObfuscator: free to use with no account. An optional Pro plan adds larger files, batch obfuscation, string encryption, control-flow obfuscation and an HTTP API for CI/CD.
Capabilities side by side
| Capability | Obfuscar | FreeObfuscator |
|---|---|---|
| Symbol renaming | Yes | Yes |
| Control-flow obfuscation We add it; Obfuscar does not | No | Yes |
| String encryption We add it; Obfuscar does not | No | Yes |
| Runs locally We process server-side | Yes | No |
| No size limit 100 MB on Pro | Yes | Partial |
| Fine-grained exclusions We use built-in safe rules | Yes | No |
| Zero configuration | No | Yes |
| MSBuild integration | Yes | No |
| HTTP API for CI Pro plan | No | Paid tier |
| Works from any OS | Yes | Yes |
Where Obfuscar is strong
- Genuinely maintained, unlike much of this category.
- Runs locally — nothing leaves your network.
- MSBuild integration, so it runs as part of a normal build.
- Fine-grained XML control over exactly what is excluded from renaming.
- Free and open source with no size limits.
Where it costs you
- Configuration is an XML file you must write and maintain.
- Getting exclusions right for a reflective application takes iteration.
- Nothing to try before committing — you configure first, then find out.
- Renaming only — no string-encryption or control-flow layer, which we now add.
Choosing between them
Choose Obfuscar if
- You want renaming permanently wired into MSBuild.
- Your code cannot leave your network.
- You need precise control over what is excluded from renaming.
- You have large assemblies or high volume and want no limits.
Choose FreeObfuscator if
- You do not want to write and maintain an obfuscation config.
- You want to see the result on your assembly before committing to anything.
- You would rather call an HTTP API than add a build dependency.
- You need to protect something once, not on every build.
The verdict
This is the fairest comparison on the list, because we are solving the same problem. Obfuscar gives you local execution and precise control at the cost of writing configuration; we give you zero configuration at the cost of uploading the file and accepting our built-in rules about what is safe to rename. If your code cannot leave your network, that decides it — use Obfuscar.
Worth knowing before you decide: what obfuscation actually protects against sets realistic expectations about how far any of these tools go.