Drop-in for Swifty repos
Reads the same repo.json and mod.srf files — the JSON format and the legacy
text one — and reproduces the official MD5 checksum chain. Your repository works unchanged.
Arma 3 addon manager
Stop paying disk space for the same mods twice.
Nimby installs from your community's existing Swifty repository, but it never downloads a byte it can get locally. Content that already sits in your Steam Workshop cache or in a shared mod store is linked into the workspace instead of copied.
What it does
Built for communities that already run a Swifty repository, and for players who would rather not keep four copies of CBA on four drives.
Reuses the Workshop
Most mods in an Arma repo carry a publishedid. A full match becomes a junction, a partial
match an overlay of hardlinks plus only the missing files.
Shared mod store
Download a file once into one folder and hardlink it into as many repositories and workspaces as you like. The store is optional, and can be pruned.
Tracking index
.nimby/tracking.json records every installed file: where it came from, where it lives, its
link kind and a size+mtime signature. Updates become a stat call instead of a full rehash.
Parallel, byte-exact downloads
8 MiB range requests, four workers per file, per-mod bars with transfer rate, ETA, live cancel and resume. Everything is verified against the manifest, part by part.
Portable and open
One zip, no installer, no registry. Configuration and the hash cache live in data\ next to
the executable. The whole thing is GPL-3.0-or-later on GitHub.
How it saves disk
For every file in the manifest Nimby looks for identical bytes — size first, then the MD5 of each part — in the Steam Workshop cache and in the shared store. Only what is missing is fetched.
| Mode | When it is used | Result | Extra disk |
|---|---|---|---|
dir-link | every file matches a Workshop item or the store | junction or symlink of the @mod folder | 0 |
overlay | some files match | hardlinks for those, download the rest | only the rest |
copy | links are impossible (exFAT, network share) | copies the bytes | full |
passthrough | opt-in | launch straight from the source folder | 0 |
78 s → 8.4 scold install of three mods, one request per manifest part versus 8 MiB chunks with four workers
6.2 s → 5.2 s138 MB across five mods, one at a time versus two mods in parallel
39 MBtransferred by a resume after cancelling at 6 % of a 476 MB mod, instead of 476 MB
Measured against a live Swifty repository with a cold cache. Junctions and hardlinks need no administrator rights; symlinks are the fallback, copying the last resort.
What you actually see
Six working pages plus an About page, no wizard, no tray app. Everything the UI does is a CLI call, so it can be scripted.
-mod= command line.
First run in five minutes
The zip is self-contained: extract it anywhere you can write, including a USB stick.
- Extract and run
Nimby.exeNothing is installed and nothing is written outside the folder you extract to. - Add your repositoryRepositories → paste the community URL → Add. It becomes the active repo.
- Pick a workspace rootConfiguration → Workspace root, for example
E:\Nimby. Every repository gets its own subfolder there. - Install and launchTick the mods, press Install, then Launch. Workshop content is linked, the rest is downloaded.
SmartScreen will warn you. The build is not code-signed. Verify the SHA-256 of the zip
against SHA256SUMS.txt instead of trusting the download:
Get-FileHash .\nimby-0.9.0-win-x64.zip -Algorithm SHA256Requirements
Windows 10 or 11 x64 and Arma 3 from Steam. The .NET runtime is bundled, so there is nothing else to
install. The CLI lives in bin\nimby.exe; keep it next to the GUI.
Ready when your repository is
Coming from Swifty? nimby migrate imports
your Arma path, scratch folder, workspace, repositories and launch parameters.