F# Guide — Paket: Dependency Management for .NET

In this tutorial, you will learn about F# Guide. We cover key concepts, practical examples, and best practices to help you master this topic.

Paket is a dependency manager for .NET projects that complements NuGet with centralized version management, transitive dependency resolution, and support for multiple package sources.

What You'll Learn

• Setting up Paket
• paket.dependencies and paket.lock
• Managing NuGet packages
• Version consolidation
• File references and GitHub dependencies

Why It Matters

Paket gives precise control over dependencies, prevents version conflicts, and supports dependency groups for different environments. Durga Antivirus Pro uses Paket for its .NET components.

Real-World Use

Large .NET projects with complex dependency graphs benefit from Paket's centralized version management and transitive dependency control.

flowchart LR
    A["Paket"] --> B["Installation"]
    B --> C["paket.dependencies"]
    C --> D["Lock File"]
    D --> E["Version Mgmt"]
    A:::current --> B
    style A fill:#2563eb,stroke:#2563eb,color:#fff
    style B fill:#dbeafe,stroke:#2563eb,color:#1e40af
    style C fill:#dbeafe,stroke:#2563eb,color:#1e40af
    style D fill:#dbeafe,stroke:#2563eb,color:#1e40af
    style E fill:#f1f5f9,stroke:#94a3b8,color:#64748b

Installation

# Install Paket globally
dotnet tool install Paket --global

# Initialize in project
paket init

# Add NuGet source
paket add nuget FSharp.Data --project MyProject.fsproj

# Install dependencies
paket install

paket.dependencies

// paket.dependencies
source https://api.nuget.org/v3/index.json

nuget FSharp.Core >= 6.0
nuget FSharp.Data >= 5.0
nuget Newtonsoft.Json >= 13.0

// Group for test dependencies
group Test
    source https://api.nuget.org/v3/index.json
    nuget xunit >= 2.4
    nuget FsCheck >= 2.14

paket.references

// MyProject/paket.references
FSharp.Core
FSharp.Data
Newtonsoft.Json

// MyProject.Tests/paket.rereferences
group Test
    xunit
    FsCheck

Adding Packages

# Add single package
paket add nuget Serilog --project MyApp.fsproj

# Add to specific group
paket add nuget xunit --group Test --project MyApp.Tests.fsproj

# Convert from packages.config
paket convert-from-nuget

Version Constraints

// paket.dependencies version syntax
nuget FSharp.Core >= 6.0           // Minimum version
nuget FSharp.Data ~> 5.0           // Compatible version (5.x)
nuget Newtonsoft.Json >= 13.0 < 14.0  // Range
nuget MyLib prerelease              // Include prerelease

Updating Dependencies

# Update all packages
paket update

# Update specific package
paket update nuget FSharp.Data

# Show outdated packages
paket outdated

# Why a package is included
paket why FSharp.Data

Common Mistakes

1. Mixing Paket and NuGet

Don't use both Paket and packages.config. Choose one approach.

2. Forgetting paket install

Always run paket install after modifying paket.dependencies.

3. Committing paket.lock

Always commit paket.lock for reproducible builds.

4. Incorrect version constraints

Overly restrictive versions cause conflicts. Use compatible version ranges.

5. Ignoring transitive dependencies

Paket resolves transitive deps. Run paket show-installed to see the full graph.

Practice Questions

1. What is Paket? An alternative .NET dependency manager that provides centralized version control and transitive dependency resolution.

2. How is Paket different from NuGet? Paket uses a single paket.dependencies file for all projects, separate paket.references per project, and a lock file for reproducibility.

3. What is the paket.lock file used for? It records the exact versions and dependency graph, ensuring reproducible builds across environments.

Challenge: Set up Paket for a multi-project solution with shared and test-specific dependencies.

FAQ

{{< faq question="Should I use Paket or NuGet?" >} For simple projects, NuGet is fine. For multi-project solutions with complex dependencies, Paket's centralized control and lock file are beneficial. {{< /faq >}}

{{< faq question="Can I use both Paket and NuGet?" >} Not recommended. Choose one approach. Paket can replace NuGet entirely for dependency management. {{< /faq >}}

{{< faq question="Is Paket still maintained?" >} Yes. Paket is actively maintained by the F# community and the .NET Foundation. {{< /faq >}}

{{< faq question="How does Paket handle transitive dependencies?" >} Paket resolves the dependency graph and consolidates versions. The lock file records exact transitive versions. {{< /faq >}}

{{< faq question="Can Paket download dependencies from GitHub?" >} Yes. Paket supports file references from GitHub repos and HTTP sources, not just NuGet. {{< /faq >}}

Mini Project

Set up Paket for a solution with shared and test dependencies:

// paket.dependencies
source https://api.nuget.org/v3/index.json

nuget FSharp.Core ~> 7.0
nuget FSharp.Data

group Test
    source https://api.nuget.org/v3/index.json
    nuget xunit ~> 2.4
    nuget FsCheck
    nuget FsUnit

// src/MyApp/paket.references
FSharp.Core
FSharp.Data

// tests/MyApp.Tests/paket.references
group Test
    xunit
    FsCheck
    FsUnit

What's Next

Now that you understand Paket, explore common F# libraries and the ecosystem.