12. API Reference

This section describes the functional API for interacting with Pkg.jl. It is recommended to use the functional API, rather than the Pkg REPL mode, for non-interactive usage, for example in scripts.

General API Reference

Certain options are generally useful and can be specified in any API call. You can specify these options by setting keyword arguments.

Redirecting output

Use the io::IOBuffer keyword argument to redirect Pkg output. For example, Pkg.add("Example"; io=devnull) will discard any output produced by the add call.

Package API Reference

In the Pkg REPL mode, packages (with associated version, UUID, URL etc) are parsed from strings, for example "Package#master","Package@v0.1", "www.mypkg.com/MyPkg#my/feature".

In the functional API, it is possible to use strings as arguments for simple commands (like Pkg.add(["PackageA", "PackageB"]), but more complicated commands, which e.g. specify URLs or version range, require the use of a more structured format over strings. This is done by creating an instance of PackageSpec which is passed in to functions.

Pkg.add(pkg::Union{String, Vector{String}}; preserve=PRESERVE_TIERED)
Pkg.add(pkg::Union{PackageSpec, Vector{PackageSpec}}; preserve=PRESERVE_TIERED)

Add a package to the current project. This package will be available by using the import and using keywords in the Julia REPL, and if the current project is a package, also inside that package.

Resolution Tiers

Pkg resolves the set of packages in your environment using a tiered algorithm. The preserve keyword argument allows you to key into a specific tier in the resolve algorithm. The following table describes the argument values for preserve (in order of strictness):

PRESERVE_ALL_INSTALLEDLike PRESERVE_ALL and only add those already installed
PRESERVE_ALLPreserve the state of all existing dependencies (including recursive dependencies)
PRESERVE_DIRECTPreserve the state of all existing direct dependencies
PRESERVE_SEMVERPreserve semver-compatible versions of direct dependencies
PRESERVE_NONEDo not attempt to preserve any version information
PRESERVE_TIEREDUse the tier that will preserve the most version information while
allowing version resolution to succeed (this is the default)

To change the default strategy to PRESERVE_TIERED_INSTALLED set the env var JULIA_PKG_PRESERVE_TIERED_INSTALLED to true.

After the installation of new packages the project will be precompiled. For more information see pkg> ?precompile.

With the PRESERVE_ALL_INSTALLED strategy the newly added packages will likely already be precompiled, but if not this may be because either the combination of package versions resolved in this environment has not been resolved and precompiled before, or the precompile cache has been deleted by the LRU cache storage (see JULIA_MAX_NUM_PRECOMPILE_FILES).

Julia 1.9

The PRESERVE_TIERED_INSTALLED and PRESERVE_ALL_INSTALLED strategies requires at least Julia 1.9.


Pkg.add("Example") # Add a package from registry
Pkg.add("Example"; preserve=Pkg.PRESERVE_ALL) # Add the `Example` package and strictly preserve existing dependencies
Pkg.add(name="Example", version="0.3") # Specify version; latest release in the 0.3 series
Pkg.add(name="Example", version="0.3.1") # Specify version; exact release
Pkg.add(url="https://github.com/JuliaLang/Example.jl", rev="master") # From url to remote gitrepo
Pkg.add(url="/remote/mycompany/juliapackages/OurPackage") # From path to local gitrepo
Pkg.add(url="https://github.com/Company/MonoRepo", subdir="juliapkgs/Package.jl)") # With subdir

After the installation of new packages the project will be precompiled. See more at Environment Precompilation.

See also PackageSpec, Pkg.develop.

Pkg.develop(pkg::Union{String, Vector{String}}; io::IO=stderr, preserve=PRESERVE_TIERED, installed=false)
Pkg.develop(pkgs::Union{PackageSpec, Vector{PackageSpec}}; io::IO=stderr, preserve=PRESERVE_TIERED, installed=false)

Make a package available for development by tracking it by path. If pkg is given with only a name or by a URL, the package will be downloaded to the location specified by the environment variable JULIA_PKG_DEVDIR, with joinpath(DEPOT_PATH[1],"dev") being the default.

If pkg is given as a local path, the package at that path will be tracked.

The preserve strategies offered by Pkg.add are also available via the preserve kwarg. See Pkg.add for more information.


# By name

# By url

# By path

See also PackageSpec, Pkg.add.

Pkg.activate([s::String]; shared::Bool=false, io::IO=stderr)
Pkg.activate(; temp::Bool=false, shared::Bool=false, io::IO=stderr)

Activate the environment at s. The active environment is the environment that is modified by executing package commands. The logic for what path is activated is as follows:

  • If shared is true, the first existing environment named s from the depots in the depot stack will be activated. If no such environment exists, create and activate that environment in the first depot.
  • If temp is true this will create and activate a temporary environment which will be deleted when the julia process is exited.
  • If s is an existing path, then activate the environment at that path.
  • If s is a package in the current project and s is tracking a path, then activate the environment at the tracked path.
  • Otherwise, s is interpreted as a non-existing path, which is then activated.

If no argument is given to activate, then use the first project found in LOAD_PATH.


Pkg.activate(; temp=true)
Pkg.rm(pkg::Union{String, Vector{String}}; mode::PackageMode = PKGMODE_PROJECT)
Pkg.rm(pkg::Union{PackageSpec, Vector{PackageSpec}}; mode::PackageMode = PKGMODE_PROJECT)

Remove a package from the current project. If mode is equal to PKGMODE_MANIFEST also remove it from the manifest including all recursive dependencies of pkg.

See also PackageSpec, PackageMode.

Pkg.update(; level::UpgradeLevel=UPLEVEL_MAJOR, mode::PackageMode = PKGMODE_PROJECT, preserve::PreserveLevel)
Pkg.update(pkg::Union{String, Vector{String}})
Pkg.update(pkg::Union{PackageSpec, Vector{PackageSpec}})

If no positional argument is given, update all packages in the manifest if mode is PKGMODE_MANIFEST and packages in both manifest and project if mode is PKGMODE_PROJECT. If no positional argument is given, level can be used to control by how much packages are allowed to be upgraded (major, minor, patch, fixed).

If packages are given as positional arguments, the preserve argument can be used to control what other packages are allowed to update:

  • PRESERVE_ALL (default): Only allow pkg to update.
  • PRESERVE_DIRECT: Only allow pkg and indirect dependencies that are not a direct dependency in the project to update.
  • PRESERVE_NONE: Allow pkg and all its indirect dependencies to update.

After any package updates the project will be precompiled. See more at Environment Precompilation.

See also PackageSpec, PackageMode, UpgradeLevel.

Pkg.test(; kwargs...)
Pkg.test(pkg::Union{String, Vector{String}; kwargs...)
Pkg.test(pkgs::Union{PackageSpec, Vector{PackageSpec}}; kwargs...)

Keyword arguments:

  • coverage::Bool=false: enable or disable generation of coverage statistics.
  • allow_reresolve::Bool=true: allow Pkg to reresolve the package versions in the test environment
  • julia_args::Union{Cmd, Vector{String}}: options to be passed the test process.
  • test_args::Union{Cmd, Vector{String}}: test arguments (ARGS) available in the test process.
Julia 1.9

allow_reresolve requires at least Julia 1.9.

Run the tests for package pkg, or for the current project (which thus needs to be a package) if no positional argument is given to Pkg.test. A package is tested by running its test/runtests.jl file.

The tests are run by generating a temporary environment with only the pkg package and its (recursive) dependencies in it. If a manifest file exists and the allow_reresolve keyword argument is set to false, the versions in the manifest file are used. Otherwise a feasible set of packages is resolved and installed.

During the tests, test-specific dependencies are active, which are given in the project file as e.g.

Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"

test = ["Test"]

The tests are executed in a new process with check-bounds=yes and by default startup-file=no. If using the startup file (~/.julia/config/startup.jl) is desired, start julia with --startup-file=yes. Inlining of functions during testing can be disabled (for better coverage accuracy) by starting julia with --inline=no. The tests can be run as if different command line arguments were passed to julia by passing the arguments instead to the julia_args keyword argument, e.g.

Pkg.test("foo"; julia_args=["--inline"])

To pass some command line arguments to be used in the tests themselves, pass the arguments to the test_args keyword argument. These could be used to control the code being tested, or to control the tests in some way. For example, the tests could have optional additional tests:

if "--extended" in ARGS
    @test some_function()

which could be enabled by testing with

Pkg.test("foo"; test_args=["--extended"])
Pkg.build(; verbose = false, io::IO=stderr)
Pkg.build(pkg::Union{String, Vector{String}}; verbose = false, io::IO=stderr)
Pkg.build(pkgs::Union{PackageSpec, Vector{PackageSpec}}; verbose = false, io::IO=stderr)

Run the build script in deps/build.jl for pkg and all of its dependencies in depth-first recursive order. If no argument is given to build, the current project is built, which thus needs to be a package. This function is called automatically on any package that gets installed for the first time. verbose = true prints the build output to stdout/stderr instead of redirecting to the build.log file.

Pkg.pin(pkg::Union{String, Vector{String}}; io::IO=stderr, all_pkgs::Bool=false)
Pkg.pin(pkgs::Union{PackageSpec, Vector{PackageSpec}}; io::IO=stderr, all_pkgs::Bool=false)

Pin a package to the current version (or the one given in the PackageSpec) or to a certain git revision. A pinned package is never automatically updated: if pkg is tracking a path, or a repository, those remain tracked but will not update. To get updates from the origin path or remote repository the package must first be freed.

Julia 1.7

The all_pkgs kwarg was introduced in julia 1.7.


Pkg.pin(name="Example", version="0.3.1")
Pkg.pin(all_pkgs = true)
Pkg.free(pkg::Union{String, Vector{String}}; io::IO=stderr, all_pkgs::Bool=false)
Pkg.free(pkgs::Union{PackageSpec, Vector{PackageSpec}}; io::IO=stderr, all_pkgs::Bool=false)

If pkg is pinned, remove the pin. If pkg is tracking a path, e.g. after Pkg.develop, go back to tracking registered versions. To free all dependencies set all_pkgs=true.

Julia 1.7

The all_pkgs kwarg was introduced in julia 1.7.


Pkg.free(all_pkgs = true)
Pkg.instantiate(; verbose = false, io::IO=stderr)

If a Manifest.toml file exists in the active project, download all the packages declared in that manifest. Otherwise, resolve a set of feasible packages from the Project.toml files and install them. verbose = true prints the build output to stdout/stderr instead of redirecting to the build.log file. If no Project.toml exist in the current active project, create one with all the dependencies in the manifest and instantiate the resulting project.

After packages have been installed the project will be precompiled. See more at Environment Precompilation.

Pkg.resolve(; io::IO=stderr)

Update the current manifest with potential changes to the dependency graph from packages that are tracking a path.

Pkg.gc(; collect_delay::Period=Day(7), io::IO=stderr)

Garbage-collect package and artifact installations by sweeping over all known Manifest.toml and Artifacts.toml files, noting those that have been deleted, and then finding artifacts and packages that are thereafter not used by any other projects, marking them as "orphaned". This method will only remove orphaned objects (package versions, artifacts, and scratch spaces) that have been continually un-used for a period of collect_delay; which defaults to seven days.

Pkg.status([pkgs...]; outdated::Bool=false, mode::PackageMode=PKGMODE_PROJECT, diff::Bool=false, compat::Bool=false, extensions::Bool=false, io::IO=stdout)

Print out the status of the project/manifest.

Packages marked with have new versions that can be installed, e.g. via Pkg.up. Those marked with have new versions available, but cannot be installed due to compatibility conflicts with other packages. To see why, set the keyword argument outdated=true.

Setting outdated=true will only show packages that are not on the latest version, their maximum version and why they are not on the latest version (either due to other packages holding them back due to compatibility constraints, or due to compatibility in the project file). As an example, a status output like:

pkg> Pkg.status(; outdated=true)
Status `Manifest.toml`
⌃ [a8cc5b0e] Crayons v2.0.0 [<v3.0.0], (<v4.0.4)
⌅ [b8a86587] NearestNeighbors v0.4.8 (<v0.4.9) [compat]
⌅ [2ab3a3ac] LogExpFunctions v0.2.5 (<v0.3.0): SpecialFunctions

means that the latest version of Crayons is 4.0.4 but the latest version compatible with the [compat] section in the current project is 3.0.0. The latest version of NearestNeighbors is 0.4.9 but due to compat constrains in the project it is held back to 0.4.8. The latest version of LogExpFunctions is 0.3.0 but SpecialFunctions is holding it back to 0.2.5.

If mode is PKGMODE_PROJECT, print out status only about the packages that are in the project (explicitly added). If mode is PKGMODE_MANIFEST, print status also about those in the manifest (recursive dependencies). If there are any packages listed as arguments, the output will be limited to those packages.

Setting ext=true will show dependencies with extensions and what extension dependencies of those that are currently loaded.

Setting diff=true will, if the environment is in a git repository, limit the output to the difference as compared to the last git commit.

See Pkg.project and Pkg.dependencies to get the project/manifest status as a Julia object instead of printing it.

Julia 1.8

The and indicators were added in Julia 1.8. The outdated keyword argument requires at least Julia 1.8.


Interactively edit the [compat] entries within the current Project.

Pkg.compat(pkg::String, compat::String)

Set the [compat] string for the given package within the current Project.

See Compatibility for more information on the project [compat] section.

Pkg.precompile(; strict::Bool=false, timing::Bool=false)
Pkg.precompile(pkg; strict::Bool=false, timing::Bool=false)
Pkg.precompile(pkgs; strict::Bool=false, timing::Bool=false)

Precompile all or specific dependencies of the project in parallel.

Set timing=true to show the duration of the precompilation of each dependency.


Errors will only throw when precompiling the top-level dependencies, given that not all manifest dependencies may be loaded by the top-level dependencies on the given system. This can be overridden to make errors in all dependencies throw by setting the kwarg strict to true


This method is called automatically after any Pkg action that changes the manifest. Any packages that have previously errored during precompilation won't be retried in auto mode until they have changed. To disable automatic precompilation set ENV["JULIA_PKG_PRECOMPILE_AUTO"]=0. To manually control the number of tasks used set ENV["JULIA_NUM_PRECOMPILE_TASKS"].

Julia 1.8

Specifying packages to precompile requires at least Julia 1.8.

Julia 1.9

Timing mode requires at least Julia 1.9.


Pkg.precompile(["Foo", "Bar"])

Enable (b=true) or disable (b=false) offline mode.

In offline mode Pkg tries to do as much as possible without connecting to internet. For example, when adding a package Pkg only considers versions that are already downloaded in version resolution.

To work in offline mode across Julia sessions you can set the environment variable JULIA_PKG_OFFLINE to "true".

Pkg.why(pkg::Union{String, Vector{String}})
Pkg.why(pkg::Union{PackageSpec, Vector{PackageSpec}})

Show the reason why this package is in the manifest. The output is all the different ways to reach the package through the dependency graph starting from the dependencies.

Julia 1.9

This function requires at least Julia 1.9.

Pkg.dependencies()::Dict{UUID, PackageInfo}

This feature is considered experimental.

Query the dependency graph of the active project. The result is a Dict that maps a package UUID to a PackageInfo struct representing the dependency (a package).

PackageInfo fields

nameThe name of the package
versionThe version of the package (this is Nothing for stdlibs)
tree_hashA file hash of the package directory tree
is_direct_depThe package is a direct dependency
is_pinnedWhether a package is pinned
is_tracking_pathWhether a package is tracking a path
is_tracking_repoWhether a package is tracking a repository
is_tracking_registryWhether a package is being tracked by registry i.e. not by path nor by repository
git_revisionThe git revision when tracking by repository
git_sourceThe git source when tracking by repository
sourceThe directory containing the source code for that package
dependenciesThe dependencies of that package as a vector of UUIDs

Enable (b=true) or disable (b=false) respecting versions that are in the sysimage (enabled by default).

If this option is enabled, Pkg will only install packages that have been put into the sysimage (e.g. via PackageCompiler) at the version of the package in the sysimage. Also, trying to add a package at a URL or develop a package that is in the sysimage will error.


This feature is considered experimental.

Request a ProjectInfo struct which contains information about the active project.

ProjectInfo fields

nameThe project's name
uuidThe project's UUID
versionThe project's version
ispackageWhether the project is a package (has a name and uuid)
dependenciesThe project's direct dependencies as a Dict which maps dependency name to dependency UUID
pathThe location of the project file which defines the active project

Undoes the latest change to the active project. Only states in the current session are stored, up to a maximum of 50 states.

See also: redo.

    domain::AbstractString = "github.com",
    protocol::Union{Nothing, AbstractString}=nothing

Set the protocol used to access hosted packages when adding a url or developing a package. Defaults to delegating the choice to the package developer (protocol === nothing). Other choices for protocol are "https" or "git".


julia> Pkg.setprotocol!(domain = "github.com", protocol = "ssh")

julia> Pkg.setprotocol!(domain = "gitlab.mycompany.com")
PackageSpec(name::String, [uuid::UUID, version::VersionNumber])
PackageSpec(; name, url, path, subdir, rev, version, mode, level)

A PackageSpec is a representation of a package with various metadata. This includes:

  • The name of the package.
  • The package's unique uuid.
  • A version (for example when adding a package). When upgrading, can also be an instance of the enum UpgradeLevel. If the version is given as a String this means that unspecified versions are "free", for example version="0.5" allows any version 0.5.x to be installed. If given as a VersionNumber, the exact version is used, for example version=v"0.5.3".
  • A url and an optional git revision. rev can be a branch name or a git commit SHA1.
  • A local path. This is equivalent to using the url argument but can be more descriptive.
  • A subdir which can be used when adding a package that is not in the root of a repository.

Most functions in Pkg take a Vector of PackageSpec and do the operation on all the packages in the vector.

Many functions that take a PackageSpec or a Vector{PackageSpec} can be called with a more concise notation with NamedTuples. For example, Pkg.add can be called either as the explicit or concise versions as:

Pkg.add(PackageSpec(name="Package"))Pkg.add(name = "Package")
Pkg.add(PackageSpec(url="www.myhost.com/MyPkg")))Pkg.add(name = "Package")
Pkg.add([PackageSpec(name="Package"), PackageSpec(path="/MyPkg"])Pkg.add([(;name="Package"), (;path="MyPkg")])

Below is a comparison between the REPL mode and the functional API:

Package@0.2PackageSpec(name="Package", version="0.2")
-PackageSpec(name="Package", version=v"0.2.1")
Package=a67d...PackageSpec(name="Package", uuid="a67d...")
Package#masterPackageSpec(name="Package", rev="master")
local/path#featurePackageSpec(path="local/path"; rev="feature")
--major PackagePackageSpec(name="Package", version=UPLEVEL_MAJOR)

An enum with the instances


Determines how much a package is allowed to be updated. Used as an argument to PackageSpec or as an argument to Pkg.update.


Registry API Reference

The functional API for registries uses RegistrySpecs, similar to PackageSpec.

RegistrySpec(; name, url, path)

A RegistrySpec is a representation of a registry with various metadata, much like PackageSpec.

Most registry functions in Pkg take a Vector of RegistrySpec and do the operation on all the registries in the vector.


Below is a comparison between the REPL mode and the functional API::

MyRegistry=a67d...RegistrySpec(name="MyRegistry", uuid="a67d...")

Add new package registries.

The no-argument Pkg.Registry.add() will install the default registries.


Pkg.Registry.add(RegistrySpec(uuid = "23338594-aafe-5451-b93e-139f81909106"))
Pkg.Registry.add(RegistrySpec(url = "https://github.com/JuliaRegistries/General.git"))

Remove registries.


Pkg.Registry.rm(RegistrySpec(uuid = "23338594-aafe-5451-b93e-139f81909106"))

Update registries. If no registries are given, update all available registries.


Pkg.Registry.update(RegistrySpec(uuid = "23338594-aafe-5451-b93e-139f81909106"))

Display information about available registries.



Artifacts API Reference


Creates a new artifact by running f(artifact_path), hashing the result, and moving it to the artifact store (~/.julia/artifacts on a typical installation). Returns the identifying tree hash of this artifact.

remove_artifact(hash::SHA1; honor_overrides::Bool=false)

Removes the given artifact (identified by its SHA1 git tree hash) from disk. Note that if an artifact is installed in multiple depots, it will be removed from all of them. If an overridden artifact is requested for removal, it will be silently ignored; this method will never attempt to remove an overridden artifact.

In general, we recommend that you use Pkg.gc() to manage artifact installations and do not use remove_artifact() directly, as it can be difficult to know if an artifact is being used by another package.

verify_artifact(hash::SHA1; honor_overrides::Bool=false)

Verifies that the given artifact (identified by its SHA1 git tree hash) is installed on- disk, and retains its integrity. If the given artifact is overridden, skips the verification unless honor_overrides is set to true.

bind_artifact!(artifacts_toml::String, name::String, hash::SHA1;
               platform::Union{AbstractPlatform,Nothing} = nothing,
               download_info::Union{Vector{Tuple},Nothing} = nothing,
               lazy::Bool = false,
               force::Bool = false)

Writes a mapping of name -> hash within the given (Julia)Artifacts.toml file. If platform is not nothing, this artifact is marked as platform-specific, and will be a multi-mapping. It is valid to bind multiple artifacts with the same name, but different platforms and hash'es within the same artifacts_toml. If force is set to true, this will overwrite a pre-existant mapping, otherwise an error is raised.

download_info is an optional vector that contains tuples of URLs and a hash. These URLs will be listed as possible locations where this artifact can be obtained. If lazy is set to true, even if download information is available, this artifact will not be downloaded until it is accessed via the artifact"name" syntax, or ensure_artifact_installed() is called upon it.

unbind_artifact!(artifacts_toml::String, name::String; platform = nothing)

Unbind the given name from an (Julia)Artifacts.toml file. Silently fails if no such binding exists within the file.

download_artifact(tree_hash::SHA1, tarball_url::String, tarball_hash::String;
                  verbose::Bool = false, io::IO=stderr)

Download/install an artifact into the artifact store. Returns true on success, returns an error object on failure.

Julia 1.8

As of Julia 1.8 this function returns the error object rather than false when failure occurs

ensure_artifact_installed(name::String, artifacts_toml::String;
                          platform::AbstractPlatform = HostPlatform(),
                          verbose::Bool = false,
                          quiet_download::Bool = false,

Ensures an artifact is installed, downloading it via the download information stored in artifacts_toml if necessary. Throws an error if unable to install.

                               platform = HostPlatform(),
                               pkg_uuid = nothing,
                               include_lazy = false,
                               verbose = false,
                               quiet_download = false,

Installs all non-lazy artifacts from a given (Julia)Artifacts.toml file. package_uuid must be provided to properly support overrides from Overrides.toml entries in depots.

If include_lazy is set to true, then lazy packages will be installed as well.

This function is deprecated and should be replaced with the following snippet:

artifacts = select_downloadable_artifacts(artifacts_toml; platform, include_lazy)
for name in keys(artifacts)
    ensure_artifact_installed(name, artifacts[name], artifacts_toml; platform=platform)

This function is deprecated in Julia 1.6 and will be removed in a future version. Use select_downloadable_artifacts() and ensure_artifact_installed() instead.

archive_artifact(hash::SHA1, tarball_path::String; honor_overrides::Bool=false)

Archive an artifact into a tarball stored at tarball_path, returns the SHA256 of the resultant tarball as a hexadecimal string. Throws an error if the artifact does not exist. If the artifact is overridden, throws an error unless honor_overrides is set.