Package manager for the Nim programming language.
Nimrod Shell


Nimble Build Status

Nimble is a beta-grade package manager for the Nim programming language.

Interested in learning how to create a package? Skip directly to that section here.



Nimble has some runtime dependencies on external tools, these tools are used to download Nimble packages. For instance, if a package is hosted on Github you require to have git installed and added to your environment PATH. Same goes for Mercurial repositories on Bitbucket. Nimble packages are typically hosted in Git repositories so you may be able to get away without installing Mercurial.

Warning: Ensure that you have a fairly recent version of Git installed. If the version is less recent than 1.9.0 then Nimble may have trouble using it. See this issue for more info.


Nimble is now bundled with Nim (since Nim version 0.15.0). This means that you should have Nimble installed already, as long as you have the latest version of Nim installed as well. Because of this you likely do not need to install Nimble manually.

But in case you still want to install Nimble manually, you can follow the following instructions.

There are two ways to install Nimble manually. The first is using the koch tool included in the Nim distribution and repository. Simply execute the following command to compile and install Nimble.

./koch nimble

This will clone the Nimble repository, compile Nimble and copy it into Nim's bin directory.

The second approach is to install Nimble as a Nimble package. You can do this by compiling Nimble, then running nimble install in Nimble's directory.

git clone
cd nimble
nim c src/nimble
src/nimble install

Note for Windows users: You will need to rename nimble.exe after compilation to something else like nimble1.exe, then run src\nimble1.exe install.

This will install Nimble to the default Nimble packages location: ~/.nimble/pkgs. The binary will be installed to ~/.nimble/bin, so you will need to add this directory to your PATH.

Nimble usage

Once you have Nimble installed on your system you can run the nimble command to obtain a list of available commands.

nimble refresh

The refresh command is used to fetch and update the list of Nimble packages (see below). There is no automatic update mechanism, so you need to run this yourself if you need to refresh your local list of known available Nimble packages. Example:

$ nimble refresh
Downloading package list from https://.../packages.json

Some commands may remind you to run nimble refresh or will run it for you if they fail.

You can also optionally supply this command with a URL if you would like to use a third-party package list.

Package lists can be specified in Nimble's config. Take a look at the config section below to see how to do this.

nimble install

The install command will download and install a package. You need to pass the name of the package (or packages) you want to install. If any of the packages depend on other Nimble packages Nimble will also install them. Example:

$ nimble install nake
Downloading nake into /tmp/nimble/nake...
Executing git...
nake installed successfully

Nimble always fetches and installs the latest version of a package. Note that latest version is defined as the latest tagged version in the git (or hg) repository, if the package has no tagged versions then the latest commit in the remote repository will be installed. If you already have that version installed Nimble will ask you whether you wish it to overwrite your local copy.

You can force Nimble to download the latest commit from the package's repo, for example:

$ nimble install nimgame@#head

This is of course git specific, for hg use tip instead of head. A branch, tag, or commit hash may also be specified in the place of head.

Instead of specifying a VCS branch you may also specify a version range, for example:

$ nimble install nimgame@"> 0.5"

In this case a version which is greater than 0.5 will be installed.

If you don't specify a parameter and there is a package.nimble file in your current working directory then Nimble will install the package residing in the current working directory. This can be useful for developers who are testing locally their .nimble files before submitting them to the official package list. See the Creating Packages section for more info on this.

A URL to a repository can also be specified, Nimble will automatically detect the type of the repository that the url points to and install it.

nimble uninstall

The uninstall command will remove an installed package. Attempting to remove a package which other packages depend on is disallowed and will result in an error. You must currently manually remove the reverse dependencies first.

Similar to the install command you can specify a version range, for example:

$ nimble uninstall nimgame@0.5

nimble build

The build command is mostly used by developers who want to test building their .nimble package. This command will build the package with default flags, i.e. a debug build which includes stack traces but no GDB debug information. The install command will build the package in release mode instead.

nimble c

The c (or compile, js, cc, cpp) command can be used by developers to compile individual modules inside their package. All options passed to Nimble will also be passed to the Nim compiler during compilation.

Nimble will use the backend specified in the package's .nimble file if the command c or compile is specified. The more specific js, cc, cpp can be used to override that.

nimble list

The list command will display the known list of packages available for Nimble. An optional --ver parameter can be specified to tell Nimble to query remote git repositories for the list of versions of the packages and to then print the versions. Please note however that this can be slow as each package must be queried separately.

nimble search

If you don't want to go through the whole output of the list command you can use the search command specifying as parameters the package name and/or tags you want to filter. Nimble will look into the known list of available packages and display only those that match the specified keywords (which can be substrings). Example:

$ nimble search math
  url: (hg)
  tags:        library, opengl, math, game
  description: OpenGL math library
  license:     CC0

  url:         git:// (git)
  tags:        library, math, trigonometry
  description: Nim math library
  license:     MIT

Searches are case insensitive.

An optional --ver parameter can be specified to tell Nimble to query remote git repositories for the list of versions of the packages and to then print the versions. Please note however that this can be slow as each package must be queried separately.

nimble path

The nimble path command will show the absolute path to the installed packages matching the specified parameters. Since there can be many versions of the same package installed, the path command will always show the latest version. Example:

$ nimble path argument_parser

Under Unix you can use backticks to quickly access the directory of a package, which can be useful to read the bundled documentation. Example:

$ pwd
$ cd `nimble path argument_parser`
$ less

nimble init

The nimble init command will start a simple wizard which will create a quick .nimble file for your project.

As of version 0.7.0, the .nimble file that this command creates will use the new NimScript format. Check out the Creating Packages section for more info.

nimble publish

Publishes your Nimble package to the official Nimble package repository.

Note: Requires a valid Github account.

nimble tasks

For a nimble package in the current working directory, list the tasks which that package defines. This is only supported for packages utilising the new nimscript .nimble files.

nimble dump

Outputs information about the package in the current working directory in an ini-compatible format. Useful for tools wishing to read metadata about Nimble packages who do not want to use the NimScript evaluator.


At startup Nimble will attempt to read ~/.config/nimble/nimble.ini on Linux (on Windows it will attempt to read C:\Users\<YourUser>\AppData\Roaming\nimble\nimble.ini).

The format of this file corresponds to the ini format with some Nim enhancements. For example:

nimbleDir = r"C:\Nimble\"

name = "CustomPackages"
url = ""

You can currently configure the following in this file:

  • nimbleDir - The directory which nimble uses for package installation. Default: ~/.nimble/
  • chcp - Whether to change the current code page when executing Nim application packages. If true this will add chcp 65001 to the .cmd stubs generated in ~/.nimble/bin/. Default: true
  • [PackageList] + name + url - You can use this section to specify a new custom package list. Multiple package lists can be specified. Nimble defaults to the "Official" package list, you can override it by specifying a [PackageList] section named "official". Multiple URLs can be specified under each section, Nimble will try each in succession if downloading from the first fails.
  • cloneUsingHttps - Whether to replace any git:// inside URLs with https://. Default: true
  • httpProxy - The URL of the proxy to use when downloading package listings. Nimble will also attempt to read the http_proxy and https_proxy environment variables. Default: ""

Creating Packages

Nimble works on git repositories as its primary source of packages. Its list of packages is stored in a JSON file which is freely accessible in the nim-lang/packages repository. This JSON file provides nimble with the required Git URL to clone the package and install it. Installation and build instructions are contained inside a file with the .nimble file extension. The nimble file shares the package's name, i.e. a package named "foobar" should have a corresponding foobar.nimble file.

These files specify information about the package including its the author, license, dependencies and more. Without one Nimble is not able to install a package.

A .nimble file can be created easily using Nimble's init command. This command will ask you a bunch of questions about your package, then generate a .nimble file for you.

A bare minimum .nimble file follows:

# Package

version     = "0.1.0"
author      = "Your Name"
description = "Example .nimble file."
license     = "MIT"

# Deps

requires "nim >= 0.10.0"

You may omit the dependencies entirely, but specifying the lowest version of the Nim compiler required is recommended.

You can also specify multiple dependencies like so:

# Deps

requires "nim >= 0.10.0", "foobar >= 0.1.0"
requires "fizzbuzz >= 1.0"

Nimble currently supports installation of packages from a local directory, a git repository and a mercurial repository. The .nimble file must be present in the root of the directory or repository being installed.

The .nimble file is very flexible because it is interpreted using NimScript. Because of Nim's flexibility the definitions remain declarative. With the added ability of using the Nim language to enrich your package specification. For example, you can define dependencies for specific platforms using Nim's when statement.

Another great feature is the ability to define custom Nimble package-specific commands. These are defined in the .nimble files of course.

task hello, "This is a hello task":
  echo("Hello World!")

You can then execute nimble hello, which will result in the following output:

Executing task hello in /Users/user/projects/pkg/pkg.nimble
Hello World!

You can place any Nim code inside these tasks. As long as that code does not access the FFI. The nimscript module in Nim's standard library defines additional functionality such as the ability to execute external processes which makes this feature very powerful.

You can also check what tasks are supported by the package in the current directory by using the tasks command.

Nimble provides an API which adds even more functionality. For example, you can specify pre and post hooks for any Nimble command (including commands that you define yourself). To do this you can add something like the following:

before hello:
  echo("About to call hello!")

That will result in the following output when nimble hello is executed (you must also specify the task shown above).

Executing task hello in /Users/user/projects/pkg/pkg.nimble
About to call hello!
Hello World!

Similar to this an after block is also available for post hooks, which are executed after Nimble finished executing a command. You can also return false from these blocks to stop further execution.

The nimscriptapi.nim module specifies this and includes other definitions which are also useful. Take a look at it for more information.

Project structure

There is nothing surprising about the recommended project structure. The advice resembles that of many other package managers.

Directory Purpose
. Root directory containing .nimble file.
./src/ Project source code
./tests/ Project test files
./docs/ Project documentation

Note: Nimble will by default look for source files in ., in order to use this layout you will need to specify srcDir = "src" in your .nimble file.


A common problem that arises with tests is the fact that they need to import the associated package. But the package is in the parent directory. This can be solved in a few different ways:

  • Expect that the package has been installed locally into your ~/.nimble directory.
  • Use a simple path modification to resolve the package properly.

The latter is highly recommended. Reinstalling the package to test an actively changing code base is a massive pain.

To modify the path for your tests only, simply add a nim.cfg file into your tests directory with the following contents:


To make testing even more convenient, you may wish to define a test task in your .nimble file. Like so:

task test, "Runs the test suite":
  exec "nim c -r tests/tester"

You can compile and run a single tester application or multiple test files.


Library packages are likely the most popular form of Nimble packages. They are meant to be used by other library or binary packages.

When nimble installs a library it will copy all of its files into $nimbleDir/pkgs/pkgname-ver. It's up to the package creator to make sure that the package directory layout is correct, this is so that users of the package can correctly import the package.

By convention, it is suggested that the layout be as follows. The directory layout is determined by the nature of your package, that is, whether your package exposes only one module or multiple modules.

If your package exposes only a single module, then that module should be present in the root directory (the directory with the .nimble file) of your git repository, it is recommended that in this case you name that module whatever your package's name is. A good example of this is the jester package which exposes the jester module. In this case the jester package is imported with import jester.

If your package exposes multiple modules then the modules should be in a PackageName directory. This will allow for a certain measure of isolation from other packages which expose modules with the same names. In this case the package's modules will be imported with import PackageName/module.

You are free to combine the two approaches described.

In regards to modules which you do not wish to be exposed. You should place them in a PackageName/private directory. Your modules may then import these private modules with import PackageName/private/module. This directory structure may be enforced in the future.

All files and folders in the directory of where the .nimble file resides will be copied as-is, you can however skip some directories or files by setting the skipDirs, skipFiles or skipExt options in your .nimble file. Directories and files can also be specified on a whitelist basis, if you specify either of installDirs, installFiles or installExt then Nimble will only install the files specified.

Binary packages

These are application packages which require building prior to installation. A package is automatically a binary package as soon as it sets at least one bin value, like so:

bin = @["main"]

In this case when nimble install is invoked, nimble will build the main.nim file, copy it into $nimbleDir/pkgs/pkgname-ver/ and subsequently create a symlink to the binary in $nimbleDir/bin/. On Windows a stub .cmd file is created instead.

Other files will be copied in the same way as they are for library packages.

Binary packages should not install .nim files so include skipExt = @["nim"] in your .nimble file, unless you intend for your package to be a binary/library combo which is fine.

Dependencies are automatically installed before building. It's a good idea to test that the dependencies you specified are correct by running by running nimble build or nimble install in the directory of your package.


One thing to note about library and binary package hybrids is that your binary may share the name of the package. This will mean that you will not be able to put your .nim files in a pkgname directory. The reason you will not be able to do this is because binaries on some operating systems do not have an extension so they will clash with a directory of the same name.

The current convention to get around this problem is to append pkg to the name as is done for nimble.


Dependencies are specified using the requires function. For example:

# Dependencies
requires "nim >= 0.10.0", "jester > 0.1 & <= 0.5"

Dependency lists support version ranges. These versions may either be a concrete version like 0.1, or they may contain any of the less-than (<), greater-than (>), less-than-or-equal-to (<=) and greater-than-or-equal-to (>=) oeprators. Two version ranges may be combined using the & operator, for example > 0.2 & < 1.0, which will install a package with the version greater than 0.2 and less than 1.0.

Specifying a concrete version as a dependency is not a good idea because your package may end up depending on two different versions of the same package. If this happens Nimble will refuse to install the package.

In addition to versions you may also specify git/hg tags, branches and commits. Although these have to be specific; ranges of commits are not supported. This is done with the # character, for example: jester#head. Which will make your package depend on the latest commit of Jester.

External dependencies

Warning: This feature is brand new in Nimble v0.8.0. Breaking changes related to it are more likely to be introduced than for any other Nimble features.

Starting with Nimble v0.8.0, you can now specify external dependencies. These are dependencies which are not managed by Nimble and can only be installed via your system's package manager or downloaded manually via the internet.

As an example, to specify a dependency on openssl you may put this in your .nimble file:

when defined(nimdistros):
  import distros
  if detectOs(Ubuntu):
    foreignDep "libssl-dev"
    foreignDep "openssl"

The when branch is important to support installation using older versions of Nimble.

The distros module in Nim's standard library contains a list of all the supported Operating Systems and Linux distributions.

With this inside your .nimble file, Nimble will output the following after installing your package (on macOS):

  Hint: This package requires some external dependencies.
  Hint: To install them you may be able to run:
  Hint:   sudo brew install openssl

Nim compiler

The Nim compiler cannot read .nimble files. Its knowledge of Nimble is limited to the nimblePaths feature which allows it to use packages installed in Nimble's package directory when compiling your software. This means that it cannot resolve dependencies, and it can only use the latest version of a package when compiling.

When Nimble builds your package it actually executes the Nim compiler. It resolves the dependencies and feeds the path of each package to the compiler so that it knows precisely which version to use.

This means that you can safely compile using the compiler when developing your software, but you should use nimble to build the package before publishing it to ensure that the dependencies you specified are correct.


Versions of cloned packages via git or mercurial are determined through the repository's tags.

When installing a package which needs to be downloaded, after the download is complete and if the package is distributed through a VCS, nimble will check the cloned repository's tags list. If no tags exist, nimble will simply install the HEAD (or tip in mercurial) of the repository. If tags exist, nimble will attempt to look for tags which resemble versions (e.g. v0.1) and will then find the latest version out of the available tags, once it does so it will install the package after checking out the latest version.

You can force the installation of the HEAD of the repository by specifying #head after the package name in your dependency list.

Releasing a new version

Version releases are done by creating a tag in your Git or Mercurial repository.

Whenever you want to release a new version, you should remember to first increment the version in your .nimble file and commit your changes. Only after that is done should you tag the release.

To summarise, the steps for release are:

  • Increment the version in your .nimble file.
  • Commit your changes.
  • Tag your release, by for example running git tag v0.2.0.
  • Push your tags and commits.

Once the new tag is in the remote repository, Nimble will be able to detect the new version.

Publishing packages

Publishing packages isn't a requirement. But doing so allows people to associate a specific name to a URL pointing to your package. This mapping is stored in an official packages repository located here.

This repository contains a packages.json file which lists all the published packages. It contains a set of package names with associated metadata. You can read more about this metadata in the readme for the packages repository.

To publish your package you need to fork that repository, and add an entry into the packages.json file for your package. Then create a pull request with your changes. You only need to do this once.

Nimble includes a publish command which does this for you automatically.

.nimble reference



  • name - The name of the package. (This is not required in the new NimScript format)
  • version - The current version of this package. This should be incremented before tagging the current version using git tag or hg tag.
  • author - The name of the author of this package.
  • description - A string describing the package.
  • license - The name of the license in which this package is licensed under.


  • skipDirs - A list of directory names which should be skipped during installation, separated by commas.
  • skipFiles - A list of file names which should be skipped during installation, separated by commas.
  • skipExt - A list of file extensions which should be skipped during installation, the extensions should be specified without a leading . and should be separated by commas.
  • installDirs - A list of directories which should exclusively be installed, if this option is specified nothing else will be installed except the dirs listed here, the files listed in installFiles, the files which share the extensions listed in installExt, the .nimble file and the binary (if bin is specified). Separated by commas.
  • installFiles - A list of files which should be exclusively installed, this complements installDirs and installExt. Only the files listed here, directories listed in installDirs, files which share the extension listed in installExt, the .nimble file and the binary (if bin is specified) will be installed. Separated by commas.
  • installExt - A list of file extensions which should be exclusively installed, this complements installDirs and installFiles. Separated by commas.
  • srcDir - Specifies the directory which contains the .nim source files. Default: The directory in which the .nimble file resides; i.e. root dir of the package.
  • binDir - Specifies the directory where nimble build will output binaries. Default: The directory in which the .nimble file resides; i.e. root dir of the package.
  • bin - A list of files which should be built separated by commas with no file extension required. This option turns your package into a binary package, nimble will build the files specified and install them appropriately.
  • backend - Specifies the backend which will be used to build the files listed in bin. Possible values include: c, cc, cpp, objc, js. Default: c



  • requires - Specified a list of package names with an optional version range separated by commas. Example: nim >= 0.10.0, jester; with this value your package will depend on nim version 0.10.0 or greater and on any version of jester.

Nimble's folder structure and packages

Nimble stores everything that has been installed in ~/.nimble on Unix systems and in your $home/.nimble on Windows. Libraries are stored in $nimbleDir/pkgs, and binaries are stored in $nimbleDir/bin. Most Nimble packages will provide .nim files and some documentation. The Nim compiler is aware of Nimble and will automatically find the modules so you can import modulename and have that working without additional setup.

However, some Nimble packages can provide additional tools or commands. If you don't add their location ($nimbleDir/bin) to your $PATH they will not work properly and you won't be able to run them.


  • SSL support is not available. Cannot connect over SSL. [HttpRequestError]

Make sure that nimble is configured to run with SSL, adding a -d:ssl flag to the file src/nimble.nim.cfg. After that, you can run src/nimble install and overwrite the existing installation.

  • Error: ambiguous identifier: 'version' --use nimscriptapi.version or system.version

Make sure that you are running at least version 0.16.0 of Nim (or the latest nightly).

Repository information

This repository has two main branches: master and stable.

The master branch is...

  • default
  • bleeding edge
  • tested to compile with the latest Nim version

The stable branch is...

  • installed by koch tools/koch nimble
  • relatively stable
  • should compile with Nim HEAD as well as the latest Nim version

Note: The travis build only tests whether Nimble works with the latest Nim version.

A new Nim release (via koch xz) will always bundle the latest tagged Nimble release.


If you would like to help, feel free to fork and make any additions you see fit and then send a pull request.

If you have any questions about the project you can ask me directly on github, ask on the Nim forum, or ask on Freenode in the #nim channel.


Nimble has been written by Dominik Picheta with help from a number of contributors. It is licensed under the BSD license (Look at license.txt for more info).