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 usage
- Creating Packages
- Publishing packages
- .nimble reference
- Nimble's folder structure and packages
- Repository information
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 need 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 older than 1.9.0, then Nimble may have trouble using it. See this issue for more information.
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
Simply execute the following command to compile and install Nimble.
This will clone the Nimble repository, compile Nimble and copy it into Nim's bin directory.
Once you have Nimble installed on your system you can run the
to obtain a list of available commands.
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
$ nimble refresh Downloading package list from https://.../packages.json Done.
Some commands may remind you to run
nimble refresh or will run it for you if
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.
check command will read your package's .nimble file. It will then
verify that the package's structure is valid.
$ nimble check Error: Package 'x' has an incorrect structure. It should contain a single directory hierarchy for source files, named 'x', but file 'foobar.nim' is in a directory named 'incorrect' instead. This will be an error in the future. Hint: If 'incorrect' contains source files for building 'x', rename it to 'x'. Otherwise, prevent its installation by adding `skipDirs = @["incorrect"]` to the .nimble file. Failure: Validation failed
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.
$ 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 Mercurial) 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 Mercurial, use
tip instead of
branch, tag, or commit hash may also be specified in the place of
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
.nimble files before submitting them to the official package
list. See the Creating Packages section for more info on this.
A valid URL to a Git or Merurial repository can also be specified, Nimble will automatically detect the type of the repository that the url points to and install it.
For repositories containing the Nimble package in a subdirectory, you can
instruct Nimble about the location of your package using the
query parameter. For example:
$ nimble install https://github.com/nimble-test/multi?subdir=alpha
develop command allows you to link an existing copy of a package into
your installation directory. This is so that when developing a package you
don't need to keep reinstalling it for every single change.
$ cd ~/projects/jester $ nimble develop
Any packages depending on
jester will now use the code in
If you specify a package name to this command, Nimble will clone it into the current working directory.
$ nimble develop jester
jester package will be cloned into
./jester and it will be linked
to your installation directory.
Just as with the
install command, a package URL may also be specified
instead of a name.
uninstall command will remove an installed package. Attempting to remove
a package which other packages depend on will result in an error. You can use the
-i flag to remove all dependent packages along with the package.
Similar to the
install command you can specify a version range, for example:
$ nimble uninstall firstname.lastname@example.org
build command is mostly used by developers who want to test building
.nimble package. This command will build the package with default
flags, i.e. a debug build which includes stack traces but no GDB debug
install command will build the package in release mode
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
compile is specified. The more specific
cpp can be used to override that.
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.
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
$ nimble search math linagl: url: https://bitbucket.org/BitPuffin/linagl (hg) tags: library, opengl, math, game description: OpenGL math library license: CC0 extmath: url: git://github.com/achesak/extmath.nim (git) tags: library, math, trigonometry description: Nim math library license: MIT
Searches are case insensitive.
--ver parameter can be specified to tell Nimble to
query remote Git repositories for the list of versions of the packages and
then print the versions. However, please note that this can be slow as each
package must be queried separately.
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
$ nimble path argument_parser /home/user/.nimble/pkgs/argument_parser-0.1.2
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 /usr/local/bin $ cd `nimble path argument_parser` $ less README.md
init command will start a simple wizard which will create
.nimble file for your project in the current directory.
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.
Publishes your Nimble package to the official Nimble package repository.
Note: Requires a valid GitHub account with an SSH key attached to it. To upload your public key onto your GitHub account, follow this link.
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.
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
The format of this file corresponds to the ini format with some Nim enhancements. For example:
nimbleDir = r"C:\Nimble\" [PackageList] name = "CustomPackages" url = "http://mydomain.org/packages.json" [PackageList] name = "Local project packages" path = r"C:\Projects\Nim\packages.json"
You can currently configure the following in this file:
nimbleDir- The directory which Nimble uses for package installation. Default:
chcp- Whether to change the current code page when executing Nim application packages. If
truethis will add
chcp 65001to the .cmd stubs generated in
path) - 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. Alternately,
pathcan specify a local file path to copy a package list .json file from.
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
https_proxyenvironment variables. Default: ""
nimLibPrefix- Specifies the Nim standard library prefix to help Nimble find the Nim standard library. Default: ""
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
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
These files specify information about the package including its 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 in the current directory.
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
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
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
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
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
false from these blocks to stop further execution.
nimscriptapi.nim module specifies this and includes other definitions
which are also useful. Take a look at it for more information.
For a package named "foobar", the recommended project structure is the following:
. # The root directory of the project ├── LICENSE ├── README.md ├── foobar.nimble # The project .nimble file └── src └── foobar.nim # Imported via `import foobar` └── tests # Contains the tests ├── nim.cfg ├── tfoo1.nim # First test └── tfoo2.nim # Second test
Note that the .nimble file needs to be in the project's root directory. This
directory structure will be created if you run
nimble init inside a
Warning: When source files are placed in a
src directory, the
.nimble file must contain a
srcDir = "src" directive. The
command takes care of that for you.
When introducing more modules into your package, you should place them in a
separate directory named
foobar (i.e. your package's name). For example:
. # The root directory of the project ├── ... ├── foobar.nimble # The project .nimble file ├── src │ ├── foobar │ │ ├── utils.nim # Imported via `import foobar/utils` │ │ └── common.nim # Imported via `import foobar/common` │ └── foobar.nim # Imported via `import foobar` └── ...
You may wish to hide certain modules in your package from the users. Create a
private directory for that purpose. For example:
. # The root directory of the project ├── ... ├── foobar.nimble # The project .nimble file ├── src │ ├── foobar │ │ ├── private │ │ │ └── hidden.nim # Imported via `import foobar/private/hidden` │ │ ├── utils.nim # Imported via `import foobar/utils` │ │ └── common.nim # Imported via `import foobar/common` │ └── foobar.nim # Imported via `import foobar` └── ...
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
- 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
tests directory with the following contents:
Nimble offers a pre-defined
test task which compiles and runs all files
tests directory beginning with 't' in their filename.
You may wish to override this
test task in your
.nimble file. This
is particularly useful when you have a single test suite program. Just add
the following to your
.nimble file to override the default
task test, "Runs the test suite": exec "nim c -r tests/tester"
nimble test will now use the
test task you have defined.
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
$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.
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, and should be named whatever your package's name is. A good example
of this is the jester package which exposes
jester module. In this case the jester package is imported with
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
Here's a simple example multi-module library package called
. ├── kool │ ├── useful.nim │ └── also_useful.nim └── kool.nimble
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
skipExt options in your .nimble file.
Directories and files can also be specified on a whitelist basis, if you
specify either of
Nimble will only install the files specified.
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
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
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
Dependencies are automatically installed before building.
It's a good idea to test that the dependencies you specified are correct by
nimble build or
nimble install in the directory
of your package.
One thing to note about binary packages that contain source files aside from
the one(s) specified in
bin (or that also expose multiple library modules, as
above) is that a binary may share the name of the package: this will mean
that you will not be able to put your additional .nim files in a
directory. The reason for this is that binaries on some operating systems do
not have an extension, so they will clash with a directory of the same name.
If this is the case, you should place your additional .nim files in a directory
pkg appended after the name of the project. For instance, if you were
building a binary named
project, you would put any additional source files in
a directory called
projectpkg. From within project.nim you would then import
those modules namespaced with
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
0.1, or they may contain any of the less-than (
>), less-than-or-equal-to (
<=) and greater-than-or-equal-to
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/Mercurial tags, branches and commits.
Although these have to be specific; ranges of commits are not supported.
This is done with the
jester#head. Which will make your package depend on the
latest commit of Jester.
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" else: foreignDep "openssl"
when branch is important to support installation using older versions
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: brew install openssl
The Nim compiler cannot read .nimble files. Its knowledge of Nimble is
limited to the
nimblePath 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.
nim after changing the nimble directory
The Nim compiler has been preconfigured to look at the default nimble directory while compiling,
so no extra step is required to use nimble managed packages in your code.
However, if you are using a custom
nimbleDir, you need to specify the
--nimblePath:PATH option. For example,
nimble directory is located at
/some/custom/path/nimble, this should work:
nim c --nimblePath:/some/custom/path/nimble/pkgs main.nim
Some code editors rely on
nim check to check for errors under the hood (e.g. VScode),
and the editor extension may not allow users to pass custom option to
nim check, which
nim check to scream
Error: cannot open file:<the_package>. In this case,
you will have to use Nim compiler's configuration files. Simply add the line:
nimblePath = "/some/custom/path/nimble/pkgs"
nim.cfg located in any directory listed in the documentation, this should resolve the problem.
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
- 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 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
packages.json file for your package. Then create a pull request
with your changes. You only need to do this
Nimble includes a
publish command which does this for you automatically.
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
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
binis specified). Separated by commas.
installFiles- A list of files which should be exclusively installed, this complements
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
binis specified) will be installed. Separated by commas.
installExt- A list of file extensions which should be exclusively installed, this complements
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 buildwill 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:
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
nimversion 0.10.0 or greater and on any version of
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
flag to the file
After that, you can run
src/nimble install and overwrite the existing
Could not download: error:14077410:SSL routines:SSL23_GET_SERVER_HELLO:sslv3 alert handshake failure
If you are on macOS, you need to set and export the
DYLD_LIBRARY_PATH environment variable to the directory where your OpenSSL libraries are. For example, if you use OpenSSL, you have to set
export DYLD_LIBRARY_PATH=/usr/local/opt/openssl/lib in your
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).
Error: cannot open '/home/user/.nimble/lib/system.nim'.
Nimble cannot find the Nim standard library. This is considered a bug so
please report it. As a workaround you can set the
variable to the directory where
lib/system.nim (and other standard library
files) are found. Alternatively you can also configure this in Nimble's
This repository has two main branches:
master branch is...
- bleeding edge
- tested to compile with a pinned (close to HEAD) commit of Nim
stable branch is...
- installed by
- 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
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.
These files are created by Nimble when using the
develop command. They
are very simple and contain two lines.
The first line: Always a path to the
The second line: Always a path to the Nimble package's source code. Usually
$pkgDir/src, depending on what
srcDir is set to.
The paths written by Nimble are always absolute. But Nimble (and the
Nim compiler) also supports relative paths, which will be read relative to