Helm vs. Kustomize: Which Is Better for K8s Config?

Discussions about Helm versus Kustomize are often framed as an either-or decision, which oversimplifies the problem. In practice, they address different layers of configuration management. Helm functions as a Kubernetes package manager, well-suited for installing, upgrading, and managing the lifecycle of complex applications with many moving parts. Kustomize focuses on declarative, environment-specific customization, enabling teams to apply overlays without introducing a separate templating language.

Mature platform teams increasingly combine both approaches: Helm to consume and version upstream applications, and Kustomize to adapt those deployments to specific environments. This guide moves beyond surface-level comparisons to examine the underlying design philosophies of each tool and shows how a hybrid model, orchestrated through a GitOps platform like Plural, can simplify and standardize Kubernetes workflows.

Key takeaways:

• Use Helm for packaging and Kustomize for customization: Helm is ideal for distributing versioned applications and managing complex dependencies, while Kustomize excels at applying simple, declarative patches to manage environment-specific configurations without templating.
• Combine both tools for a flexible workflow: A hybrid approach is often best. Use Helm to deploy a base application from a chart, then use Kustomize to apply targeted, environment-specific overlays, separating core application logic from custom tweaks.
• Automate fleet-wide management with GitOps: Managing a hybrid strategy at scale requires automation. Plural’s continuous deployment platform unifies your workflow by applying Helm, Kustomize, or raw YAML configurations from Git across your entire fleet, ensuring consistency and auditability.

What Are Helm and Kustomize?

When managing Kubernetes configurations, Helm and Kustomize are often compared as competing tools. In practice, they solve different problems. Helm focuses on packaging and lifecycle management, while Kustomize focuses on declarative, environment-specific customization. Understanding their design goals clarifies when—and how—to use each effectively.

Helm: The Kubernetes Package Manager

Helm functions as a package manager for Kubernetes. Applications are distributed as charts, which bundle Kubernetes manifests, default configuration values, and version metadata. Helm uses Go templates combined with values files to parameterize deployments across environments.

This model is well-suited for managing complex applications with many moving parts. Helm provides explicit lifecycle operations—install, upgrade, rollback—and tracks release history, making it easier to manage upgrades and recover from failed deployments. The tradeoff is increased abstraction and indirection due to templating.

Kustomize: Declarative Configuration Customization

Kustomize is a template-free configuration customization tool built directly into kubectl. It operates on a base-and-overlay model, where a shared base configuration is modified through overlays using patches and transformations.

Because Kustomize works with plain YAML, it preserves readability and aligns naturally with GitOps workflows. Rather than generating manifests from templates, it applies deterministic changes to existing resources. This makes it a strong choice for teams that want minimal abstraction and fine-grained, declarative control over environment-specific differences.

How Do Helm and Kustomize Work?

Helm and Kustomize take fundamentally different approaches to managing Kubernetes configuration. Helm renders manifests from templates, while Kustomize mutates existing manifests through overlays. This distinction drives differences in workflow, complexity, and how teams manage environment-specific deployments.

Helm’s Templating Model

Helm operates as a Kubernetes package manager. Applications are distributed as charts, which bundle manifests, default configuration, and version metadata. Internally, Helm uses Go templates to generate Kubernetes YAML at deploy time.

Chart templates contain placeholders such as {{ .Values.replicaCount }} that are resolved using one or more value files. This allows a single chart to support multiple environments by swapping configuration inputs. The rendered manifests only exist after the templating step, which adds flexibility but also introduces indirection when debugging or reviewing output.

Kustomize’s Overlay and Patching Model

Kustomize avoids templating entirely. It starts with fully valid Kubernetes YAML in a shared base and applies environment-specific changes via overlays. Each overlay defines patches and transformations that modify the base without duplicating it.

Because all inputs are plain YAML, every file is independently readable, lintable, and reviewable. Kustomize does not generate new manifests from templates; it deterministically transforms existing ones. This makes configuration diffs explicit and simplifies reasoning about what changes between environments.

Core Design Differences

Helm is a packaging and rendering system. It combines templates and values to produce manifests, which makes it well-suited for distributing configurable, reusable software with lifecycle management and versioning.

Kustomize is a transformation engine. It operates on complete manifests from the start, applying declarative patches to adapt them for specific contexts. This makes it particularly effective for managing environment drift in internal services and GitOps-driven workflows.

In short, Helm generates configuration, while Kustomize customizes configuration. Understanding that distinction is key to choosing—or combining—them effectively.

Helm vs. Kustomize: A Head-to-Head Comparison

Helm and Kustomize are two of the most commonly used tools for managing Kubernetes configuration, but they solve different problems. Helm is a package manager that bundles applications into reusable charts. Kustomize is a template-free customization tool that modifies declarative YAML. The differences in learning curve, templating model, ecosystem, and GitOps fit determine where each tool is most effective.

Learning Curve and Operational Complexity

Kustomize has a relatively shallow learning curve for teams already fluent in Kubernetes YAML. It introduces no new language and focuses on applying targeted, declarative changes to existing manifests. This makes it well-suited for internal services and environment-specific configuration.

Helm has a higher conceptual overhead. Teams must learn charts, releases, values, and Go templating. In return, Helm provides full lifecycle management, versioning, and rollback support. Security concerns from early Helm versions are no longer relevant; Helm v3 removed Tiller and relies entirely on Kubernetes RBAC.

YAML Handling and Templating

The core technical difference is how each tool treats YAML. Helm uses Go templates to generate manifests at deploy time. Templates are parameterized with values files, enabling highly reusable and dynamic packages, but the templates themselves are not valid YAML until rendered.

Kustomize operates only on valid YAML. A shared base defines common resources, and overlays apply patches to adjust behavior per environment. Changes are explicit, minimal, and easy to inspect, which simplifies reviews and debugging.

Ecosystem and Community Adoption

Helm has the largest ecosystem by far. It is the de facto standard for distributing third-party Kubernetes software, with thousands of maintained charts available via Artifact Hub. This makes Helm the default choice for installing complex external systems.

Kustomize is not a distribution mechanism, but it is built directly into kubectl, giving it first-class status in the Kubernetes toolchain. In practice, many teams combine the two: Helm installs third-party applications, and Kustomize applies organization-specific patches. Platforms like Plural often support and formalize this layered approach.

GitOps and Version Control Fit

Kustomize aligns naturally with GitOps. All configuration is plain YAML, and overlays produce clean, readable diffs. A pull request shows exactly what changed and why.

Helm can also be used in GitOps workflows, but it typically requires an in-cluster controller to reconcile releases. An alternative is to render charts to YAML and commit the output, which restores full declarative visibility at the cost of an extra build step.

In short, Helm excels at packaging and distributing applications, while Kustomize excels at managing environment-specific configuration. The choice is less about “either-or” and more about how they fit together in your deployment model.

Pros and Cons of Helm vs. Kustomize

Choosing between Helm and Kustomize comes down to trade-offs between packaging power and configuration simplicity. Helm optimizes for reuse and lifecycle management. Kustomize optimizes for clarity and controlled customization. Understanding where each excels helps teams pick the right tool—or combination—for their workflows.

Helm Pros: Packaging, Reuse, and Rollbacks

Helm’s core strength is its role as a Kubernetes package manager. Charts bundle manifests, defaults, and version metadata into reusable units that can be shared via public or private repositories. This makes Helm highly effective for installing and managing complex third-party systems.

Helm also provides strong lifecycle primitives. Upgrades and rollbacks are first-class operations, allowing teams to revert failed releases quickly without manual intervention. In production environments, this built-in release tracking is a significant operational advantage.

Helm Cons: Templating Complexity

Helm’s flexibility comes at the cost of complexity. Go templating can quickly become difficult to read and reason about as conditionals, loops, and nested values accumulate. The rendered output is not visible until deploy time, which can obscure misconfigurations and complicate debugging.

While Helm v3 resolved earlier security concerns by removing Tiller and relying on native Kubernetes RBAC, maintaining large charts still requires discipline. Poorly structured templates and sprawling values files can create long-term maintenance issues.

Kustomize Pros: Simplicity and Explicit Customization

Kustomize takes a template-free approach. It works entirely with valid Kubernetes YAML, applying overlays and patches to a shared base. This keeps configuration readable and makes environment-specific differences explicit.

The overlay model is well-suited for managing dev, staging, and production variations without duplication. Because all changes are declarative and diff cleanly, Kustomize aligns naturally with GitOps workflows and code review practices.

Kustomize Cons: No Packaging or Lifecycle Management

Kustomize is not a distribution or release management tool. There is no equivalent to a chart repository, and no built-in concept of install, upgrade, or rollback. It only produces customized manifests.

As a result, lifecycle concerns are typically handled by external systems—Git history, CI/CD pipelines, or GitOps controllers. This is acceptable for internal services, but limiting for teams that need reusable, versioned application bundles.

Practical Takeaway

Helm is strongest when you need to package, distribute, and manage application lifecycles. Kustomize is strongest when you need transparent, environment-specific customization of existing manifests. Many teams combine both approaches, and platforms like Plural are designed to support this layered model without forcing a single tool choice.

When to Use Helm

Helm is the right choice when application complexity, reuse, and lifecycle management matter more than raw YAML simplicity. While Kustomize is excellent for patching and environment-specific customization, Helm provides a structured system for packaging, distributing, and operating applications over time. If your deployments are non-trivial or consumed by others, Helm’s abstractions are usually justified.

Complex Applications with Multiple Dependencies

Helm is designed to manage complexity. Charts can encode relationships between multiple services, optional components, and conditional resources using Go templating. This makes Helm well-suited for applications with many dependencies or deployment modes.

For example, a single chart can conditionally deploy a database, enable or disable background workers, or tune resource limits based on supplied values. This kind of dynamic behavior is difficult to express cleanly with pure YAML overlays and is where Helm’s templating model provides real leverage.

Distributing and Installing Third-Party Software

Helm is the industry standard for distributing Kubernetes software. Most widely used infrastructure components—monitoring stacks, ingress controllers, service meshes—are published as Helm charts. This allows users to install complex systems with a single command while still retaining configurability.

If you are shipping software to customers or internal teams to run in their own clusters, Helm provides a familiar, versioned, and well-supported delivery mechanism. Platforms like Plural build on this convention to standardize how third-party and internal applications are packaged and installed.

Release Management, Versioning, and Rollbacks

Helm includes native release management. Each install or upgrade creates a new, immutable release with associated metadata and history. This makes rollbacks a first-class operation rather than an external concern.

If a deployment introduces a regression, reverting to a known-good state is a single command. This operational safety net is a key reason teams adopt Helm for production workloads. Kustomize intentionally avoids lifecycle concepts, leaving versioning and rollback responsibilities to Git history and external tooling.

Practical Guidance

Use Helm when you need packaging, reuse, dependency management, and reliable rollbacks. Its abstractions add complexity, but they pay off when operating sophisticated systems at scale. For many teams, Helm handles distribution and lifecycle concerns, while tools like Kustomize or Plural are layered on top to manage environment-specific customization.

When to Use Kustomize

Kustomize is the right choice when your primary concern is managing Kubernetes configuration declaratively across environments. Unlike Helm, it avoids packaging and templating in favor of directly customizing valid YAML. This makes it well-suited for teams that value simplicity, readability, and tight alignment with GitOps workflows.

Managing Environment-Specific Configuration

Kustomize excels at handling environment variance without duplication. A shared base defines common resources, and overlays apply only the differences needed for each environment.

For example, a base Deployment may define two replicas. A production overlay can patch that value to ten and add resource limits, while a development overlay can change the image tag or enable debugging flags. This keeps configuration DRY and makes environment-specific differences explicit and easy to reason about.

Prioritizing Simplicity and Readability

If your team prefers working directly with standard Kubernetes YAML, Kustomize is a natural fit. There is no templating language and no indirection through values files. Patches are declarative and written in plain YAML.

Because the configuration closely resembles what is applied to the cluster, debugging is simpler, and pull requests are easier to review. Engineers do not need to mentally execute a rendering step to understand the final state.

GitOps and Patch-Based Workflows

Kustomize aligns naturally with GitOps principles. All configuration lives in Git, and changes are expressed as small, targeted patches. A diff clearly shows what is being modified—an annotation, an image tag, or a resource limit—rather than an abstract change in a values file.

In platforms like Plural, Kustomize overlays stored in Git can be automatically reconciled across fleets of clusters. Plural’s GitOps agent detects changes and applies the appropriate overlays to the correct environments, ensuring configuration consistency without manual intervention.

Practical Guidance

Use Kustomize when you want transparent, declarative control over environment-specific configuration and are comfortable managing application lifecycle concerns outside the tool itself. It complements Helm well, especially when Helm handles packaging and distribution and Kustomize handles environment customization.

Using Helm and Kustomize Together

Helm and Kustomize are often positioned as alternatives, but they are more effective when used together. Helm handles packaging, distribution, and lifecycle management. Kustomize handles declarative, environment-specific customization. Combining them produces a flexible model where Helm defines the application and Kustomize defines how it runs in each context.

A Hybrid Strategy: Clear Separation of Concerns

A common pattern is to use Helm as the authoritative definition of an application’s structure and dependencies, then layer Kustomize on top for customization. Platform teams own and version Helm charts. Application or environment teams apply Kustomize overlays without forking or modifying upstream charts.

For example, a shared Helm chart can define a Prometheus stack. Individual teams then use Kustomize to add scrape targets, alerts, or environment-specific annotations. This prevents configuration drift, avoids chart sprawl, and keeps responsibilities cleanly separated.

Customizing Helm Charts with Kustomize

Kustomize can treat Helm charts as inputs. In a kustomization.yaml, you can reference a Helm chart, pin a version, and provide values. Kustomize renders the chart and then applies patches on top of the rendered manifests.

This approach is especially useful when you need targeted changes that would otherwise require complex Helm templating. You can patch rendered resources to inject sidecars, add node selectors, modify security contexts, or apply organization-wide policies—all without touching the original chart. Upgrading the chart becomes simpler because customizations remain isolated and declarative.

Operating the Hybrid Model with Plural

At scale, coordinating Helm and Kustomize across many clusters becomes an operational problem. Plural is designed to manage this hybrid model in a GitOps-native way. Helm charts and Kustomize overlays live in Git, and Plural reconciles them automatically across clusters.

Platform teams can maintain standardized Helm charts in central repositories. Application teams manage Kustomize overlays per environment. Plural’s agent applies the correct combination to each cluster, ensuring consistency without manual orchestration. This model preserves flexibility for teams while enforcing platform-level standards.

Practical Takeaway

Helm and Kustomize are complementary, not competing, tools. Helm defines and distributes applications. Kustomize adapts them to real-world environments. When combined—and managed through a platform like Plural—they form a scalable, maintainable configuration strategy for Kubernetes teams.

Overcome Common Configuration Challenges

Regardless of whether you use Helm, Kustomize, or both, teams eventually run into the same operational challenges: debugging, sharing configuration across teams, and enforcing security consistently. How each tool addresses these concerns has a direct impact on maintainability at scale.

Debugging and Configuration Visibility

Helm’s templating system is expressive but opaque. Complex charts with nested conditionals and loops can fail in non-obvious ways, producing large volumes of rendered YAML from a small mistake. Tools like helm lint catch syntax errors, but logical issues typically require rendering the chart and manually inspecting the output, which slows down debugging.

Kustomize avoids this class of problem entirely. Since all inputs are valid YAML and changes are applied through explicit patches, failures are localized. If something breaks, the issue is usually traceable to a specific overlay or patch, making root-cause analysis faster and more predictable.

Sharing Configuration Across Teams

Helm is purpose-built for sharing and reuse. Charts are versioned, packaged, and distributed through repositories, which makes them ideal for standardizing applications across teams. This is why most third-party Kubernetes software is distributed as Helm charts: consumers get a consistent base with controlled customization via values.

Kustomize supports sharing through shared Git-based bases, but it lacks formal packaging, dependency management, and versioning semantics. This works well for internal services but becomes limiting when configuration needs to be distributed broadly or consumed by many independent teams.

Security and Compliance Enforcement

Kustomize is particularly strong for enforcing security and compliance policies. Platform teams can apply mandatory overlays that inject security contexts, network policies, or labels across all workloads without requiring changes to application manifests. This cleanly separates platform concerns from application ownership.

With Helm, security controls are typically exposed as values that must be set correctly by chart consumers. While flexible, this increases the risk of misconfiguration if defaults are unsafe or values are omitted.

Plural mitigates this risk by enforcing a GitOps-based workflow where all configuration changes flow through version control and review. Using Plural’s fleet-level capabilities, platform teams can synchronize global RBAC rules and baseline security configuration across clusters, ensuring compliance is enforced consistently even when Helm charts are involved.

Practical Takeaway

Helm excels at distribution and reuse but can be harder to debug and govern without strong conventions. Kustomize trades flexibility for clarity and control, especially around security and environment drift. In practice, many teams combine both and rely on platforms like Plural to impose structure, reviewability, and consistency across the entire Kubernetes fleet.

Related Articles

• Managing Kubernetes Resources with Helm: A Practical Guide

Frequently Asked Questions

Do I have to choose between Helm and Kustomize? Not at all. Framing it as a strict choice is a common misconception. The most effective approach is often to use them together. You can use Helm to deploy third-party applications or manage the core structure of your own services, and then use Kustomize to apply the final layer of environment-specific configurations. This gives you the packaging benefits of Helm and the declarative, template-free customization of Kustomize.

Which tool is better for a beginner learning Kubernetes? If you're just starting, I recommend getting comfortable with Kustomize first. Because it works directly with standard Kubernetes YAML, it forces you to learn the fundamentals of Kubernetes objects without the added abstraction of a templating language. Once you have a solid grasp of raw manifests, learning Helm will be much easier, and you'll have a better understanding of what its templates are actually generating.

Is Kustomize replacing Helm? No, Kustomize is not replacing Helm. The two tools serve different primary purposes. Helm is a package manager designed for distributing and managing the lifecycle of applications, complete with versioning and rollbacks. Kustomize is a configuration customizer built to manage variations of YAML manifests. While their capabilities can overlap, Helm's rich ecosystem of public charts for third-party software is something Kustomize isn't designed to replicate.

How do I manage sensitive information like secrets with these tools? Neither Helm nor Kustomize is a complete secrets management solution on its own. You should never commit plain-text secrets to your Git repository. The best practice is to integrate these tools with a dedicated secrets manager, such as HashiCorp Vault or cloud-provider solutions. For a GitOps workflow, you can use tools like Sealed Secrets, which encrypts secrets so they can be safely stored in Git. Kustomize has a secretGenerator feature, and Helm can be extended with plugins like Helm Secrets to handle encrypted credentials.

How does a hybrid approach work in a real-world CI/CD pipeline? In a typical CI/CD pipeline, you would set up distinct stages. The first stage might use a helm template command to render the base YAML manifests from a chart into a temporary directory. A subsequent stage would then run kustomize build on that directory, applying the environment-specific overlays for your target (e.g., staging or production). The final output is pure, validated YAML that can be applied to your cluster. Platforms like Plural automate this entire workflow, managing the process based on changes in your Git repository.