Harness 3.0
Harness 3.0
Last updated Feb 2026

Harness 3.0 Documentation

Internal product documentation for Harness Engineers, Sales Engineers, Customer Engineers, Professional Services, and Product Management. This documentation is also intended for Beta customers evaluating the Harness 3.0 platform.

Who This Is For

This documentation is written for the following audiences. Each persona will find relevant sections tailored to their needs.

  • Harness Engineers -- Building and maintaining the Harness 3.0 platform, including backend services, frontend components, and infrastructure.
  • Sales Engineers -- Preparing and delivering demos, understanding feature capabilities, and articulating technical differentiators.
  • Customer Engineers -- Assisting customers with onboarding, troubleshooting, and advanced configuration of the platform.
  • Professional Services -- Implementing end-to-end solutions for enterprise customers, including migration planning and best practices.
  • Product Management -- Understanding current capabilities, feature status, and the 2026 roadmap to inform planning and prioritization.
  • Beta Customers -- Evaluating Harness 3.0, understanding new capabilities, and providing feedback during the beta program.

What's Covered

This documentation is organized into the following major sections. Select any topic to navigate directly to the relevant content.

The Goal: 30 Seconds to Developer Love

Harness 3.0 is a ground-up rethink of the platform with a single guiding principle: developers should fall in love with Harness within 30 seconds of using it. Every improvement -- from simplified YAML to unified steps to an AI-first UX -- is designed to eliminate friction and make CI/CD delightful.

Simplified YAML

Harness 3.0 introduces a new YAML specification (v1) that achieves an 89% reduction in YAML boilerplate. The v1 format is compatible with GitHub Actions and Drone, making it familiar to developers and easy to adopt. The v1 schema is defined in the spec repository.

ng-pipeline.yamlyaml
1# Harness NG (v0 YAML)

2pipeline:

3  name: Deploy

4  identifier: deploy

5  projectIdentifier: proj1

6  orgIdentifier: default

7  stages:

8    - stage:

9        name: Deploy to Dev

10        identifier: deploy_dev

11        type: Deployment

12        spec:

13          deploymentType: Kubernetes

14          service:

15            serviceRef: my_service

16          environment:

17            environmentRef: dev

18            infrastructureDefinitions:

19              - identifier: k8s_dev
v1-pipeline.yamlyaml
1# Harness 3.0 (v1 YAML)

2pipeline:

3  stages:

4    - name: Deploy to Dev

5      service: my_service

6      environment:

7        name: dev

8        deploy-to: k8s_dev

9      steps:

10        - run: kubectl apply -f k8s/

Backward Compatibility

Existing NG pipelines continue to work in Harness 3.0 without modification. The platform supports both v0 and v1 YAML formats, so teams can migrate at their own pace. Refer to the Migration Guide for detailed instructions on converting existing pipelines to the v1 specification.

Templates

Templates in Harness 3.0 are fundamentally redesigned to be composable, stage-agnostic, and marketplace-ready.

  • Defined inputs and outputs -- Every template declares typed inputs and outputs, making them self-documenting and composable
  • Agnostic of stage types -- Templates are not tied to any specific stage type, making them reusable across CI, CD, and custom workflows
  • Container-based tasks -- Templates wrap Harness container-based tasks that can be used as steps in any pipeline
  • Anything can be a template -- Services, Environments, Infrastructure definitions, steps, stages, and pipelines all support template creation
  • Template Marketplace -- Discover and share templates across your organization through a built-in marketplace

Unified Stages & Steps

Harness 3.0 eliminates stage-type coupling and unifies all steps into a container-based execution model. This fundamentally simplifies the platform and improves extensibility.

All Steps Are Containers

  • Fetched at runtime -- no pre-installation required
  • No dependency on the delegate for tooling
  • Run as Docker containers on a Kubernetes cluster or on a VM

No More Stage Types

  • Product-specific objects (services, environments, deployment configs) are decoupled from stages
  • Improved platform extensibility -- add custom steps without modifying the core platform
  • Fully customizable steps that can be shared across teams and organizations

Delegate 2.0

The Harness Delegate has been completely rebuilt for speed, size, and simplicity. Delegate 2.0 removes tooling dependencies and supports local pipeline execution.

ImprovementDetails
Faster Startup TimeSignificantly reduced cold-start and registration time
Local Pipeline ExecutionRun and test pipelines locally before pushing to production
VM & K8s SupportSelf-hosted or Harness-hosted, on VMs or Kubernetes clusters
Lightweight SizeReduced CPU and memory footprint
No Tooling DependenciesNo kubectl, helm, tanzu, or terraform binaries coupled with the runner

Improved UX

Harness 3.0 provides an AI-first, developer-first user experience. The entire platform has been redesigned to surface intelligent assistance at every step -- from pipeline creation to debugging failed deployments.

Watch the Harness 3.0 Demo

See the new AI-first developer experience in action

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