Overview

RAP Builder (relsvr-rap) is a command-line tool for building Relativity Application Packages (RAPs) targeting Relativity Server. It validates your application components, verifies SDK compatibility, and produces a properly structured .rap file ready for deployment.

Server RAP Builder is only supported for building applications that run in Relativity Server environments. The tool does not support applications that need to run in Relativity aiR, and Relativity currently has no intention to add support for Relativity aiR.

Looking Ahead: The Server 2026 RAP Builder Requirement

RAP Builder is not required for Server 2025. Starting in Server 2026, building RAPs with RAP Builder becomes a requirement - Relativity will also verify a RAP's compatibility when it's imported into a Server 2026 environment. If you want to get ahead of that requirement, this documentation shows you how to start using RAP Builder now to produce RAPs. For what this compatibility check looks like, see the Server 2026 documentation's Application Compatibility Verification in Relativity.

For Relativity Server 2026, third-party developers should use Server RAP Builder together with the supported Relativity Server SDK packages from the Server Artifactory feeds. This is no longer just the preferred approach. Starting in Server 2026, a RAP that is not built and validated with Server RAP Builder and the supported Server SDKs falls outside Relativity's supported build path. Even if a RAP can still be uploaded or installed, Relativity Support and Engineering may not provide troubleshooting assistance for issues related to applications built with Relativity aiR packages, custom or unmanaged dependency handling, or older manual packaging methods.

This expectation builds on the SDK changes introduced in Relativity Server 2023, when Server SDK packages were separated from Relativity aiR packages and moved off nuget.org to dedicated Relativity Server Artifactory feeds. For Server 2026, both pieces matter: developers must use the correct Server SDKs, and they must also use Server RAP Builder to create the RAP itself. RAP Builder is the only way to produce a RAP that Relativity recognizes as compatible. If an application is compiled against the correct Server SDKs but the RAP is created without Server RAP Builder, it will still be flagged as unsupported in the Application Library and Relativity Applications pages.

Before building for Server 2026, make sure your application uses the Relativity Server Artifactory feeds, the provided nuget.config and package source mapping guidance, and Server-specific SDK references, and that Server RAP Builder is used as the final packaging step. Third-party developers should review the following documentation before updating or rebuilding a Server application:

What is a RAP?

A Relativity Application Package (RAP) is a distributable archive containing all the components needed by a Relativity Server application - compiled .NET assemblies, custom pages, resource files, and an application schema. RAP Builder automates the creation of these packages from your build artifacts.

Key Features

  • Automated RAP packaging - Bundles assemblies, custom pages, and resource files into a .rap archive.
  • Schema validation - Cross-references your build.xml and application.xml to catch mismatches before deployment.
  • SDK version verification - Validates that your assemblies reference the correct Relativity Server SDK versions for your target release.
  • Hash generation - Automatically computes SHA1 hashes for assemblies and custom pages.
  • Flexible integration - Run standalone from the command line or integrate into your MSBuild/dotnet build pipeline.

Guides

Guide Description
Getting Started Install RAP Builder and build a RAP.
CLI: build Command Complete reference for the build command and its arguments.
Configuration Reference Schema details for build.xml and application.xml.
Validation and Errors Understanding validation output, error messages, and SDK checks.
Troubleshooting Common issues and solutions.
Migration Guide Migrate from manual packaging or Publish to Relativity Tool.

Requirements

RAP Builder releases are available for download on the GitHub releases page.

  • Operating System: Windows (x64)
  • .NET 10 SDK - required to install the tool via dotnet tool.
  • Relativity Server - RAP Builder does not require Relativity Server to be installed to run. RAPs built with RAP Builder can target Relativity Server 2024 or later.
  • MSBuild or Visual Studio Build Tools - only required if you compile .NET assemblies or integrate RAP Builder into your build pipeline.
  • Node.js and npm - only required if your application includes custom pages that must be built (for example, from TypeScript or a front-end framework).

Quick Example

Copy 
# Install RAP Builder globally
dotnet tool install --global Relativity.Server.RAPTool

# Build a RAP
relsvr-rap build --source . --input DevelopmentScripts/build.xml --version 1.0.0.0 --relativity-server-release 2025

See the server-sample-rap repository for a complete working example project.

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