To exclude node_modules from Time Machine, open System Settings › General › Time Machine, click Options, add the folders to the list, and click Done. That's the only control macOS gives you, and it works one folder at a time: Time Machine has no rule that matches every folder with a given name.
Excluding a folder keeps it off your backup disk. It doesn't free any space on your Mac, and the folder still appears in Time Machine's local snapshots there, as Apple notes.
The folders worth excluding are the ones a tool can make again: installed dependencies, build output, package caches, toolchains and downloaded AI models. The ones to keep are everything you'd lose: your code and its history, settings and keys, databases, archives of shipped builds and virtual machines that hold your only copy of something.
Some tools already keep their own folders out of backups. Cargo marks Rust's build folders, and Docker Desktop leaves its disk out unless you ask. Most JavaScript and Python tools don't, so their folders are backed up every hour like your documents.
Why exclude developer folders from Time Machine?
Time Machine backs up everything on your Mac that wasn't installed with macOS. For a developer, that includes a lot of files that exist only to be thrown away and made again: thousands of packages in each project, compiled output, and caches of everything ever downloaded.
What do you gain by excluding node_modules from Time Machine?
Three things: space on the backup disk, shorter backups and a longer history.
- Space. Every gigabyte of dependencies is copied to the backup disk, and copied again when it changes.
- Time. Each backup copies what changed since the last one. Reinstalling a project's dependencies replaces thousands of files at once.
- History. Apple says Time Machine deletes the oldest backups when the backup disk is full. Folders you never restore push out older versions of files you might.
How many files are in a node_modules folder?
More than most people expect. On the Mac this post was researched on, running macOS 27, three projects' node_modules folders held about 35,000, 65,000 and 82,000 files, between 0.5 and 1.5 GB each.
Each of those files is something Time Machine checks and copies. A single install after switching branches can change most of them, and every git worktree or second checkout of a project has its own copy.
Does excluding folders free up space on your Mac?
No. Exclusions apply only to the backup disk. The folders stay on your Mac at their full size, and Apple notes that excluded items still appear in Time Machine's local snapshots.
If your Mac's own disk is full, removing the folders is what helps. The post on deleting all node_modules folders safely covers that side.
How long does Time Machine keep old backups?
Apple's schedule: hourly backups for the past 24 hours, daily backups for the past month, and weekly backups for all previous months. The oldest are removed only when the backup disk runs out of room.
That's why busy folders matter more than their size suggests. A folder that changes every day adds a new copy of what changed to each daily backup, and those copies stay for a month before the backups thin out to weekly ones.
| What you gain | What it costs |
|---|---|
| Room on the backup disk for more history | A reinstall or rebuild after a restore |
| Fewer files to copy every hour | A download, which needs a network connection |
| Faster first backup of a new Mac | Some care to keep the list current |
| Less churn when dependencies change | Nothing on your Mac's own disk |
How to exclude node_modules from Time Machine
The steps are the same in macOS 27 Golden Gate and macOS 26 Tahoe. Apple's guide for each version describes the same window.
- Choose Apple menu › System Settings, click General in the sidebar, then click Time Machine.
- Click Options.
- Click the Add button and select the folders you want to leave out. You can also drag folders from a Finder window into the list.
- Click Done.
Your backup disk appears in the list by itself; Time Machine adds it for you.
The same Options window holds Backup Frequency and, on Mac laptops with an automatic schedule, Back up on battery power. Changing the exclusions doesn't affect either.
How do you add hidden folders such as ~/.npm?
Many developer tools keep their data in folders whose names start with a period, such as ~/, ~/ or ~/. Finder hides them, so they don't appear in a normal window.
- Open your home folder in Finder (Go › Home).
- Press Shift-Command-Period to show hidden items.
- Drag the folder you want into the exclusion list in Time Machine's Options.
- Press Shift-Command-Period again to hide them.
For a folder deep inside a project, choose Go › Go to Folder in Finder, type the path of the folder that contains it, and press Return. Then drag the folder you want from that window into the list.
How do you stop excluding a folder?
Open the same Options window, select the folder in the list, click the Remove button, and click Done. Time Machine includes it again from the next backup.
Removing an entry doesn't bring back earlier versions. Backups made while the folder was excluded never had it.
Can you exclude every node_modules folder at once?
Not in Time Machine's settings. The list takes specific files and folders, and it has no way to match a name or a pattern. Each project's node_modules needs its own entry, and a project you create next week isn't covered until you add it.
You can add several folders in one go: select them together in the Add dialog, or drag several from a Finder window. Finder's search can find every folder named node_modules in your projects; drag the top one in each project, the one next to its package.json, into the list.
What did older versions of macOS call this?
| macOS version | Where the exclusion list is | Button that saves it |
|---|---|---|
| macOS 27 Golden Gate | System Settings › General › Time Machine › Options | Done |
| macOS 26 Tahoe | System Settings › General › Time Machine › Options | Done |
| macOS 13 Ventura to macOS 15 Sequoia | System Settings › General › Time Machine › Options | Done |
| macOS 12 Monterey and earlier | System Preferences › Time Machine › Options | Save |
The list itself hasn't changed in years. Only its place in the settings moved, when System Preferences became System Settings in macOS Ventura.
Which developer folders are worth excluding?
A folder is a good candidate when three things are true: it's large, it changes often, and a tool can rebuild it from something you already back up, such as a lock file or a project file. Dependencies, build output and caches pass all three.
| Folder | Where it usually is | How it comes back |
|---|---|---|
node_modules | In each JavaScript project | Reinstalled from package.json and the lock file |
.venv or venv | In each Python project | Created again from the project's requirements |
| Build output | .next, dist, .turbo, .build, build | Rebuilt on the next build |
| Xcode DerivedData | ~/Library/Developer/Xcode/DerivedData | Rebuilt by Xcode |
| Package caches | ~/.npm, ~/Library/pnpm, ~/.gradle/caches, ~/go/pkg/mod | Downloaded again when needed |
| Local AI models | ~/.ollama/models, ~/.cache/huggingface | Downloaded again, often many gigabytes |
- JavaScript dependencies and caches5–200 GB
- Local AI models20–150 GB
- Virtual machines and containers10–150 GB
- Gradle, Maven and Android10–100 GB
- Xcode DerivedData5–100 GB
- Python environments and caches2–50 GB
- Go modules and build cache1–20 GB
Typical ranges from developers' reports, collected for the app's rules catalog. Each is a total across a Mac, not one project. Simulators, from about 10 GB to several hundred, are left out to keep the scale readable.
The ranges are wide because Macs differ. The point is the order: dependencies, models and virtual machines lead, and each gigabyte Time Machine backs up is copied to the backup disk too.
Is it safe to exclude node_modules from Time Machine?
For most projects, yes. A project's node_modules can be installed again from its package.json and lock file, so the backup of your project folder already holds what's needed to rebuild it.
Two cases need care. Changes made directly to files inside node_modules are lost on a reinstall, so keep patches in the project itself. And a package version that has been removed from its registry can't be downloaded again, which matters more for old projects.
Should you exclude package caches like ~/.npm and ~/.gradle?
They're the safest of all. A cache such as the npm cache or Gradle's caches holds copies of things downloaded from the internet, and the tool downloads anything that's missing.
The cost after a restore is time and bandwidth: the first install or build of each project fetches everything again. On a slow or metered connection, that can be a reason to keep a cache you rely on.
What about Xcode's DerivedData?
DerivedData is rebuilt from your projects, so backing it up gains nothing. Apple doesn't document whether Xcode keeps it out of backups.
On the same Mac, with Xcode 27, some project folders inside DerivedData were already marked as excluded and others weren't. The shared module cache wasn't. Adding the whole ~/ folder to the list covers all of it.
What about local AI models?
Models are the largest single files many developers have, and most can be downloaded again. Excluding ~/, LM Studio's models folder or the Hugging Face cache can keep tens of gigabytes off the backup disk.
The exceptions are models you made yourself. The catalog's entry for Ollama models notes that models created from a Modelfile can't be downloaded again. Keep those, or keep the Modelfile and the base model's name somewhere that's backed up.
What about simulators and Android emulators?
Simulators in ~/ hold the apps you tested and the data they saved. Xcode can create a new simulator of any kind, but it starts empty, so excluding them loses only test data.
Android Virtual Devices, in ~/, are similar: each holds its installed apps, their data and saved states. If a device holds test accounts or data that took a while to set up, keep it backed up.
What not to exclude: anything you can't rebuild
The test is simple. If a folder disappeared, could a tool make it again from something you still have? If the answer is no, or not exactly, leave it in your backups.
| Keep backed up | Why |
|---|---|
Your project folders and their .git folders | Uncommitted work, local branches and stashes exist nowhere else |
.env files and local settings | They're usually kept out of git on purpose |
~/.ssh, ~/.gnupg, ~/.config | Keys and settings that took time to set up |
~/Library/Developer/Xcode/Archives | The dSYMs of shipped builds can't be made again |
| Database folders | Your data, not a cache |
| Virtual machines you've set up | Everything inside exists only in the machine's files |
Why not exclude your whole code folder?
Because a remote repository isn't a backup of your Mac. It holds what you pushed, not the branch you haven't pushed, the changes you haven't committed, the stash you meant to come back to or the untracked notes in the project.
Exclude the generated folders inside each project, not the projects themselves. The code is small; the dependencies next to it are what's large.
Is it safe to exclude Homebrew's folder?
Not as a whole. Homebrew keeps more than installed packages in / on Apple silicon Macs. Databases you installed with it keep their data in its var folder: PostgreSQL, for example, creates its database cluster there.
Homebrew's download cache lives in your own Caches folder instead, which Time Machine already skipped on the Mac researched for this post (more on that below). For most developers, nothing in Homebrew's main folder is worth the risk of excluding.
Is it safe to exclude ~/Library/Developer?
Not as a whole. It holds DerivedData, which rebuilds by itself, right next to Xcode's Archives, which can't be made again, and the simulators with the data you tested with. Excluding the parent folder takes all of it out of your backups.
Exclude ~/ on its own instead, and decide about simulators separately. The post on the Library Developer folder explains what each folder inside does.
What about Docker's containers and volumes?
Here the risk runs the other way. Docker Desktop leaves its virtual machine out of Time Machine by default, so your images, containers and volumes aren't backed up unless you turn on Include VM in Time Machine backups in Docker Desktop's settings, under General.
That's fine for images you can pull again. It isn't fine for a database volume that holds your only copy of something. Export that data, or turn the setting on, knowing the Docker Desktop disk image (Docker.raw) can be tens of gigabytes.
Should Time Machine back up virtual machines?
Virtual machine disks are large single files that change whenever the machine runs, so each backup can copy a large file again. That's a reason to think about them, not a reason to exclude them blindly.
If a machine holds work you can't recreate, keep it backed up, or back it up another way before you exclude it. If it's a test machine you can install again from scratch, excluding it is reasonable.
OrbStack's documentation, for example, says to add its data folder to the exclusion list if you don't want its containers, images, volumes and Linux machines backed up.
Which tools already exclude their own folders?
Apps don't need the Options list to keep a folder out of backups. Apple gives developers a property that marks a file or folder as excluded, and describes it as useful only for caches and other support files that aren't needed in a backup.
| Tool | What it keeps out of backups | Source |
|---|---|---|
| macOS | System files, apps installed with macOS, and the backup disk | Apple's Time Machine guide |
| macOS | Simulator runtime images, your Caches and Logs folders | Observed on macOS 27 |
| Docker Desktop | Its virtual machine, unless you turn the setting on | Docker's settings documentation |
| Cargo | Rust target folders, its registry and git caches | Cargo's changelog |
| Xcode | Some DerivedData project folders, not all | Observed with Xcode 27 |
| npm, pnpm, uv, Ollama | Nothing | Observed; open requests for npm, uv and Ollama |
Which folders does macOS already leave out?
Apple says Time Machine skips system files and the apps installed with macOS. If your Mac is damaged, Apple's advice is to reinstall macOS first, then use Migration Assistant to bring your files back from the backup.
On the Mac researched for this post, Time Machine also reported the user's own Caches and Logs folders, ~/ and ~/, as excluded, with nothing in the Options list. So did the system folders where simulator runtimes live. Apple's support guide doesn't list these, so treat them as observed behavior.
Are developer caches already out of your backups?
A lot of developer tools keep their caches inside your Caches folder: Homebrew's downloads, pip's cache, Swift Package Manager's cache, Playwright's browsers, Go's build cache and Yarn's cache among them.
If your Caches folder is excluded, as it was on that Mac, there's no need to add those caches to the list. The ones that need attention are the caches in hidden folders in your home folder, such as ~/, ~/, ~/, ~/ and ~/.
Does npm exclude node_modules by itself?
No. npm and pnpm leave node_modules to be backed up like any other folder: on the same Mac, none of the folders they had installed was marked. An npm proposal to mark node_modules as excluded was opened in March 2026 and was still open when this post was written.
Python's tools are in the same place. A request asking uv to keep its virtual environments out of Time Machine is open, and so is one asking Ollama for a setting to exclude its models folder. Until that changes, the Options list is how you leave them out.
What about Rust's target folders?
Cargo has done this for years. It marks each target folder it creates as excluded from Time Machine, using the same property Apple documents, and writes a small CACHEDIR.TAG file that some other backup tools recognize.
Its registry and git caches, in ~/, are marked too. Toolchains in ~/ aren't. The post on Rust's target folders and Cargo caches has the details.
How can you tell whether a folder is already excluded?
Finder doesn't show it, and neither does Get Info. A folder an app has marked isn't listed in the Options window either, so the list can look empty while several folders are already left out.
Checking a folder takes Time Machine's command-line tool. If you'd rather not use it, add the folder to the Options list anyway. Listing a folder that's already excluded does no harm.
Two kinds of exclusion, and why it matters
Time Machine keeps track of exclusions in two different ways, and they behave differently when you move, rename, copy or delete a folder. Apple's own documentation for Time Machine's command-line tool describes both.
| The Options list | A mark on the folder | |
|---|---|---|
| Who sets it | You, in System Settings | An app or a command-line tool |
| How it's stored | By the folder's location | On the folder itself |
| Shown in Options | Yes | No |
| After a move or rename | The folder is backed up again | The folder stays excluded |
| After the folder is deleted | The entry stays in the list | The mark goes with it |
What happens when you rename or move a project?
Entries in the Options list work by location, according to Howard Oakley's analysis of how Time Machine stores them. Move or rename the project, and its node_modules is no longer at the excluded path, so the next backup includes it.
The old entry stays in the list. If a folder ever appears at that path again, it's excluded again, even if it's something different. Review the list after you reorganize your projects folder.
Do marks set by tools survive copying?
Yes. Apple's documentation for the command-line tool says a mark follows the folder when it moves, and a copy keeps it. A copied target folder from a Rust project stays out of backups.
Apple also warns that some common operations on documents reset the mark, which is why it's meant for caches and support files, not your own work. Don't rely on it for anything you'd want to restore.
Is there a way to do this for every new project?
Not in macOS. The Options list only knows the folders you've added. A new project, a fresh clone or another git worktree each makes a new node_modules that Time Machine backs up until you add it.
Some developers use Asimov, an open-source command-line tool under the MIT license. It scans your home folder once a day and marks dependency folders as excluded, but only when the matching project file sits next to them, such as a node_modules folder beside a package.json.
Asimov has no window or menu: it's set up and run from Terminal. Its documentation notes that it never deletes anything and that it doesn't shrink backups you've already made.
The trade-offs to weigh before you exclude
Excluding is a bet that you'll never need the folder from a backup. For most dependency and build folders, that's a safe bet. It's worth knowing what you give up.
What happens when you restore or set up a new Mac?
Migration Assistant and a full restore bring back only what's in the backup. Your projects arrive without their node_modules, virtual environments and build output, so each one needs an install and a build before it runs.
On a good connection, that's a short wait per project. Without a connection, or behind a private registry you can no longer reach, it can be the difference between working and waiting. If you depend on one machine, plan for that.
Do old backups still hold the excluded folders?
Yes. An exclusion applies to future backups only. Copies made before you added the folder stay in the older backups, and they leave only as those backups go.
Hourly and daily backups thin out on Apple's schedule, but weekly backups stay until the disk runs out of room. So the space comes back gradually: if you exclude folders to make room on a full backup disk, expect the effect over weeks, not at once.
Do local snapshots still include excluded folders?
Yes. Apple notes it in its guide: excluded items still appear in local snapshots. Those are the hourly snapshots Time Machine keeps on your Mac's own disk for up to 24 hours.
They don't cost you usable space. macOS counts it as available and removes snapshots when space is needed. The guide to Time Machine local snapshots explains how they work.
Can you always download a dependency again?
Usually, not always. Packages and models can be removed from the place they were downloaded from, private registries can lock you out after a job ends, and an old lock file can point at versions that no longer install on a new Mac.
For a project you might need to run exactly as it was, years from now, keep its dependencies in its backup. Disk space on a backup drive is cheaper than rebuilding a project from memory.
What if you exclude something by mistake?
Remove it from the Options list, and the next backup includes it again. The gap stays, though: no backup made while it was excluded has a copy, so you can't go back to a version from that time.
That's the real risk of a broad exclusion. Prefer narrow entries, such as one project's node_modules, over a parent folder that might hold something you care about later.
Are projects on an external drive backed up at all?
Check before you rely on it. Time Machine can back up other drives connected to your Mac, but Howard Oakley notes that external volumes are excluded by default, so a drive that holds your projects may be in the Options list already.
If it's there and you want it backed up, select it in the list and click the Remove button. Then the same choices apply to the folders on it.
Other backups: iCloud Drive and third-party apps
Time Machine's list affects Time Machine and nothing else. Other places your files are copied to have their own rules.
Does excluding node_modules from Time Machine keep it out of iCloud Drive?
No. If your projects are in Desktop or Documents and Desktop & Documents Folders is turned on in iCloud Drive, their node_modules folders sync to iCloud like everything else there, whatever Time Machine's list says.
The simplest fix is to keep projects in a folder that doesn't sync, such as a Developer or Projects folder in your home folder. Moving a project out of iCloud Drive also removes it from your other devices, so check you don't need it there.
Do Backblaze, Carbon Copy Cloner and Arq follow Time Machine's list?
Each backup app keeps its own exclusion settings, so check its documentation rather than assuming. Some tools recognize a CACHEDIR.TAG file in a folder as a sign it's a cache; Cargo's changelog says it writes one so that tools can leave target folders out.
If you use more than one backup, make the same decisions in each. A folder you rely on should be in at least one of them, and a folder you can rebuild doesn't need to be in any.
A sensible exclusion list for a developer's Mac
There's no single right list, because it depends on what you build. These are reasonable starting points; add the folders that exist on your Mac and skip the ones that don't.
| Kind of work | Add to the exclusion list | Keep backed up |
|---|---|---|
| Web and JavaScript | Each project's node_modules, .next, dist, .turbo; ~/.npm; ~/Library/pnpm | Projects, .env files, local databases |
| iOS and Mac apps | ~/Library/Developer/Xcode/DerivedData, simulators you don't need data from | Archives, signing certificates, projects |
| Python and data | Each project's .venv, ~/.cache/uv, ~/.cache/huggingface | Notebooks, datasets you made, models you trained |
| Java, Kotlin and Android | ~/.gradle/caches | Emulators with data you set up, ~/.m2 artifacts you installed yourself |
| Go and Rust | ~/go/pkg/mod, ~/.rustup | Projects and their lock files |
| Local AI | ~/.ollama/models, LM Studio's models folder | Models you created or fine-tuned |
Which developer folders should you never exclude?
- Your projects folder as a whole, and any
.gitfolder - Your home folder's settings folders:
.ssh,.gnupg,.config - Xcode's Archives folder, unless shipped builds are saved somewhere else
- Database data, whether in Homebrew's folder, an app such as Postgres.app or a Docker volume
- Anything you'd need to run a project exactly as it was
How do you keep the list current?
- Add a new project's generated folders when you create or clone it.
- Look at the Options list after you rename or reorganize your projects folder, and remove entries that point nowhere.
- Recheck once or twice a year, when you add tools or start working in a new language.
- If your backup disk is getting full, look at what's largest on your Mac first. Those are the folders worth deciding about.
Should you exclude folders if your backup disk is large?
It matters less. Apple suggests a backup disk with at least twice the storage of your Mac. With that much room, Time Machine can keep a long history even with dependencies included.
Excluding still shortens backups and keeps history longer, so it's worth doing for the obvious folders. But if you'd rather back up everything and never think about it, that's a reasonable choice on a large disk.
How the app does it
Time Machine's exclusion list lives in System Settings, as above. What Wombit adds is the measuring: it scans the whole disk or any folder, reading only names, sizes and dates, and shows on its map which developer folders are large enough to be worth a decision.
Select a folder in the map or the list, and the inspector explains what it is and what removing it costs, from the catalog's entry for it. File names and paths never leave your Mac. Typical levels for the folders in this post:
- Package caches such as npm's, pnpm's store, Gradle's caches, Go's module cache, Rust's target folders and Xcode's DerivedData are Safe.
- Each project's node_modules and virtual environments are Usually safe: they come back only when you reinstall.
- Xcode's archives and Ollama's models are Review first, and Docker's disk is Usually safe, handled with Docker's own command rather than moved.
~/
**/ node_modules A JavaScript project's installed dependencies, which its package manager can install again.
Usually safe · Moves it to the Trash
~/
**/ {.venv,venv} Python virtual environment (.venv)
A Python project's virtual environment: its own Python setup with the packages installed for it.
Usually safe · Moves it to the Trash
~/
.npm/ _cacache Packages and package information npm has downloaded, kept so it doesn't download them again.
Safe · Runs npm cache clean --force
~/
Library/ pnpm/ store The shared store where pnpm keeps one copy of every package version your projects use.
Safe · Runs pnpm store prune
~/
.gradle/ caches Dependencies, build cache entries and other files that Gradle keeps for all the Java, Kotlin and Android projects you build.
Safe · Moves it to the Trash
~/
Library/ Developer/ Xcode/ DerivedData Build products, indexes and logs Xcode keeps for every project you've built.
Safe · Moves it to the Trash
~/
Library/ Developer/ Xcode/ Archives/ */ *.xcarchive Copies of each build you archived in Xcode, with the dSYM files needed to read crash reports from that build.
Review first · Moves it to the Trash
Hourly snapshots of your startup disk that Time Machine keeps on the disk itself, so you can restore files even without your backup disk.
Managed by macOS · Runs tmutil for Time Machine's own snapshots, through the helper
The app also lists Time Machine's local snapshots, with when each was made, so you can see when they're holding space. Seeing all of this is free. Cleanup and removing snapshots are PRO, one $4.99 payment with lifetime access. Every Pro tool's review is free to open, so you see what would go and why before you buy.
Frequently asked questions
Can Time Machine exclude all node_modules folders automatically?
No. The exclusion list in Time Machine's Options takes specific files and folders and has no way to match a folder name. You add each project's node_modules yourself, or use a tool that marks them for you as you create projects.
Should I back up node_modules at all?
For most projects there's no need. The project's package.json and lock file, which are backed up with the project, are enough to install the same dependencies again. Keep them backed up only for projects you must be able to run exactly as they were, offline or years from now.
Does Time Machine back up Docker containers and volumes?
Not by default. Docker Desktop leaves its virtual machine out of Time Machine unless you turn on Include VM in Time Machine backups in its General settings. If a volume holds data you can't recreate, export it or turn that setting on.
Will excluding folders from Time Machine free up space on my Mac?
No. Exclusions only keep folders off the backup disk. The folders stay on your Mac at full size, and Apple notes that excluded items still appear in Time Machine's local snapshots there.
Why doesn't my Time Machine backup get smaller after I exclude a folder?
An exclusion applies only to future backups. Copies already on the backup disk stay until Time Machine deletes those older backups to make room, and it keeps weekly backups for all previous months. The space comes back gradually.
Why don't excluded folders show in Time Machine's Options list?
Apps and tools such as Cargo and Docker Desktop mark their folders directly, and those marks aren't shown in the list. Only folders you add yourself in System Settings appear there.
Is it safe to exclude the Library folder from Time Machine?
No. Your Library folder holds app settings, mail, messages and the data of many apps. Exclude specific developer folders inside it, such as Xcode's DerivedData, never the Library folder itself.
Sources
- Exclude files from a Time Machine backup on Mac · Apple
- Back up your Mac with Time Machine · Apple
- isExcludedFromBackup · Apple
- Change your Docker Desktop settings · Docker
- Cargo changelog · The Rust Project
- Knowing what not to back up, and how · The Eclectic Light Company