Best WooCommerce WordPress Themes 2026

Top Tip: The best WooCommerce themes are the ones that handle core store pages cleanly before you add custom design or extensions.

Choosing the best WooCommerce theme in 2026 is less about visuals and more about how reliably it supports core store functionality. WooCommerce relies on standardized templates for products, shop archives, cart, and checkout, and your theme directly influences how these pages render, perform, and scale as your store grows.

All themes covered in this guide are compatible with WooCommerce on WordPress.org and provide a solid foundation for running an online store without requiring custom code. A well-built theme helps ensure predictable behavior across WooCommerce updates, cleaner template handling, and fewer layout conflicts as you add products or extensions.

If you’re considering using WooCommerce alongside a visual builder, it’s also important to understand how themes interact with page-level design tools. Some themes focus purely on store templates, while others work smoothly with builders for custom landing pages and layouts. If you are planning to use WooCommerce with a page builder, see how it works with Elementor in our dedicated guide: Best WooCommerce Elementor WordPress Themes.

This article focuses on WooCommerce themes with free versions available on WordPress.org, making them easy to test in real store conditions. The goal is to help you identify themes that handle WooCommerce fundamentals well first—before deciding whether advanced design features or premium upgrades are actually necessary.

Quick Comparison Overview

Top Tip: Use this comparison to narrow your shortlist, then test candidates on real WooCommerce pages such as product, cart, and checkout.

This table provides a high-level view of how each theme approaches WooCommerce layout, structure, and styling. All listed themes support core WooCommerce functionality, but they differ in how much layout control and styling they provide out of the box.

Use the links to jump to detailed sections below, where each theme is reviewed in terms of WooCommerce template handling, customization approach, scalability, and upgrade considerations.

Why Theme Choice Matters for WooCommerce Sites

Top Tip: A strong WooCommerce theme should handle core store templates cleanly and provide reliable defaults you can build on.

Your WordPress theme plays a central role in how WooCommerce store pages—shop, product, cart, and checkout—are structured and rendered. These templates define the browsing and purchasing experience, making theme quality a direct contributor to usability and conversion flow.

Well-built themes follow standard WooCommerce practices, ensuring templates load consistently, maintain proper markup, and remain compatible with extensions. This reduces layout breakage during WooCommerce updates and helps stores remain stable as product catalogs and functionality expand.

Theme choice also has a direct impact on performance. WooCommerce adds its own scripts, styles, and database activity, and a well-built, lightweight theme helps avoid adding excessive overhead on top of that. This becomes increasingly important on product, cart, and checkout pages, where slower load times can affect usability and conversion rates.

How to Choose the Right WooCommerce Theme for Your Store

Top Tip: Always evaluate themes on real WooCommerce pages before judging design or flexibility.

Start by confirming that the theme supports WooCommerce’s core templates cleanly. This includes the shop archive, single product pages, cart, checkout, and customer account areas. These templates form the foundation of every WooCommerce store, and themes that handle them predictably are easier to maintain and less prone to breakage over time.

Next, consider how much layout control you actually need at the theme level. Some themes prioritize stability and minimal styling, while others provide additional options through the Customizer or theme settings. The right choice depends on whether you prefer a simple, consistent store layout or more flexibility for presenting products and categories.

Performance and update compatibility should also factor into your decision. Lightweight themes with fewer dependencies tend to integrate more smoothly with WooCommerce updates and extensions. As your store grows and additional functionality is introduced, this can make a meaningful difference to long-term reliability and ease of management.

How These WooCommerce Themes Were Evaluated

Top Tip: Test themes using real products and categories to understand how layouts behave in practice.

Each theme in this guide was evaluated based on how it handles WooCommerce’s default templates, including shop archives and single product pages. The focus was on structural consistency, clarity of layout, and how reliably templates render under standard WooCommerce configurations.

Evaluation was carried out using a standard WordPress setup with WooCommerce enabled for core ecommerce functionality. Testing focused on default WooCommerce behaviour and settings, without relying on proprietary builders or non-standard workflows. Themes that depend heavily on custom logic or unconventional overrides were weighed against those that follow WooCommerce’s expected template structure.

Long-term maintainability was also considered. Themes that integrate cleanly with WordPress, demonstrate an active update history, and avoid unnecessary dependencies tend to scale more reliably as stores grow and requirements evolve.

What was intentionally excluded. Demo content quality, marketing claims, and third-party add-ons were not used as primary decision factors.

Note: This evaluation reflects a limited hands-on review of specific features and workflows, rather than an exhaustive comparison of each theme.

Free vs Pro WooCommerce Themes: What to Expect

Top Tip: If you expect your store to grow, choosing a Pro theme early can reduce layout changes and migration risks later.

Free WooCommerce themes available on WordPress.org typically support all core store functionality, including product pages, shop archives, cart, checkout, and customer accounts. This makes them suitable for testing WooCommerce behavior, validating theme compatibility, and launching smaller stores.

Pro WooCommerce themes usually build on this foundation by offering deeper layout controls, additional shop and product templates, and more granular customization options. These enhancements are focused on store presentation, consistency, and long-term flexibility rather than basic WooCommerce support.

Upgrading earlier rather than later can benefit growing WooCommerce stores. As product catalogs, settings, and extensions accumulate, changing themes or feature sets can introduce complexity over time. Starting with a Pro version helps establish a stable foundation from the outset and reduces the risk of disruptive changes as the store scales. Free versions remain useful for initial testing and validation, but long-term planning often favors committing early to the feature set you expect to rely on.

Storefront

Top Tip: Storefront is best evaluated by testing WooCommerce’s core pages before adding extra styling or extensions.

WooCommerce compatibility and templates

Storefront is the official WooCommerce theme and is built to mirror WooCommerce’s default template structure as closely as possible. Shop archives, product pages, cart, checkout, and customer account areas render using WooCommerce’s expected markup, resulting in predictable behavior across updates.

Notable features in the free version

Storefront is completely free and includes full support for WooCommerce core functionality. It provides responsive layouts, compatibility with official WooCommerce extensions, and a deliberately minimal design that prioritizes correctness over visual customization.

Performance and scalability

The theme uses a lean codebase with few abstractions, helping reduce overhead and minimize conflicts. This approach supports stable performance as product catalogs grow and makes Storefront a reliable long-term option for WooCommerce-focused sites.

Customization and layout control

Customization is handled primarily through the WordPress Customizer, child themes, or additional plugins. Storefront intentionally offers fewer built-in styling controls than multipurpose themes, providing a neutral baseline that can be extended when needed.

Pros and cons

Storefront’s main strength is its tight alignment with WooCommerce core, which results in excellent compatibility and long-term stability. The trade-off is limited design flexibility out of the box, making it less suitable for stores that require strong branding without custom development.

Pricing overview

Storefront is available free of charge. Additional features or design enhancements are typically added through official WooCommerce extensions or custom development, rather than a paid theme upgrade.

• Storefront: Free theme with full WooCommerce support

Best fit for store types

Storefront is best suited for stores that prioritize WooCommerce compatibility, predictable updates, and a clean structural foundation. It is commonly used as a reference theme, a development baseline, or a starting point for stores that plan to layer customization gradually.

If your priority is stability and adherence to WooCommerce standards rather than built-in design controls, Storefront provides one of the most reliable foundations available.

Explore Storefront →

Astra

Top Tip: Test Astra’s WooCommerce settings with a real product before enabling additional styling options.

WooCommerce compatibility and templates

Astra includes built-in support for WooCommerce and applies custom styling to core store templates such as shop archives, single product pages, cart, and checkout. The theme integrates directly with WooCommerce’s template system, allowing store pages to render consistently without manual overrides.

Notable features in the free version

The free version of Astra provides WooCommerce compatibility, responsive layouts, and basic styling controls through the WordPress Customizer. It supports standard product displays and cart functionality while maintaining a lightweight core.

Performance and scalability

Astra is designed with performance in mind, using a minimal codebase and avoiding unnecessary dependencies. This approach helps keep load times low as product catalogs expand and additional WooCommerce extensions are added.

Customization and layout control

Customization options are available through the Customizer, including layout width, typography, and basic WooCommerce settings. Astra allows users to adjust store layouts without editing theme files, making it accessible for non-developers.

Pros and cons

Astra’s strengths include speed, ease of setup, and flexible customization for WooCommerce stores. Its limitations are mostly related to advanced layout controls, which are reserved for the Pro version.

Pro pricing overview

Astra offers optional premium upgrades that unlock additional WooCommerce customization features and advanced layout controls. Pricing varies based on the selected plan and feature set.

• Astra: Free version available
• Astra Pro: Paid plans starting from $69 per year, with lifetime licensing options available

Starter templates and setup speed

Astra provides starter templates that can be imported to speed up store setup. These templates offer predefined layouts that can be customized further using standard WordPress tools.

Astra is a flexible WooCommerce-ready theme that balances performance with customization. It offers built-in controls for shop and product layouts, making it suitable for store owners who want to refine their storefront design while keeping WooCommerce templates structured.

Explore Astra →

Woostify

Top Tip: Evaluate Woostify with multiple product types to see how its defaults handle real WooCommerce layouts.

WooCommerce compatibility and templates

Woostify is built with WooCommerce support enabled by default and applies custom styling to core store templates, including shop archives, single product pages, cart, and checkout. It follows WooCommerce’s standard template structure, allowing store pages to function as expected without manual configuration.

Notable features in the free version

The free version includes WooCommerce compatibility, responsive layouts, and basic store-focused options such as product display styling and layout controls accessible through the WordPress Customizer. These features support launching a functional store without additional setup.

Performance and scalability

Woostify emphasizes a lightweight approach, aiming to reduce unnecessary scripts and styles. This design supports performance as product catalogs grow and helps maintain stable behavior when WooCommerce updates are applied.

Customization and layout control

Customization is handled through the Customizer, where users can adjust layout width, product appearance, and general store styling. Woostify keeps controls focused on WooCommerce-related layouts rather than broad multipurpose design options.

Pros and cons

Woostify’s strengths include its WooCommerce-first focus and performance-oriented structure. Its main limitation is that more advanced customization and conversion-oriented features are reserved for premium extensions.

Pro pricing overview

Woostify offers optional premium add-ons that extend WooCommerce functionality and layout control. Pricing varies depending on the selected extensions and licensing options.

• Woostify: Free version available
• Woostify Pro: Paid plans starting from $49 per year, with lifetime licensing options available

Conversion-focused store features

The theme is structured to support common ecommerce patterns, such as clear product presentation and streamlined store layouts, which can be enhanced further through optional upgrades.

Woostify is a WooCommerce-focused theme built with performance in mind. Its lightweight structure and store-specific features help keep shop and product pages fast, making it a good fit for conversion-oriented online stores.

Explore Woostify →

OceanWP

Top Tip: Enable only the OceanWP features you actively use to keep WooCommerce pages lightweight.

WooCommerce compatibility and templates

OceanWP includes built-in support for WooCommerce and applies custom styling to core store templates such as shop archives, single product pages, cart, and checkout. The theme integrates with WooCommerce’s default template structure, allowing store pages to function correctly without custom code.

Notable features in the free version

The free version provides WooCommerce compatibility, responsive layouts, and basic styling options through the WordPress Customizer. It supports standard product grids, cart functionality, and checkout layouts suitable for launching a store.

Performance and scalability

OceanWP is designed as a modular theme, allowing users to activate only the features they need. This approach helps control performance overhead as stores grow and additional WooCommerce extensions are installed.

Customization and layout control

Customization is handled primarily through the Customizer, offering control over layout width, typography, and WooCommerce page styling. OceanWP provides more layout options than minimalist themes, though this can introduce additional complexity.

Pros and cons

OceanWP’s flexibility and feature set make it suitable for a wide range of WooCommerce stores. The trade-off is that enabling too many features can impact performance if not managed carefully.

Pro pricing overview

OceanWP offers optional premium extensions that expand WooCommerce functionality and layout controls. Pricing varies based on the selected extensions and licensing model.

• OceanWP: Free version available
• OceanWP Pro: Paid extensions and bundles starting from $44 per year

Useful WooCommerce add-ons to consider

OceanWP’s ecosystem includes extensions that enhance product display, cart behavior, and user experience, allowing stores to add features incrementally as needed.

OceanWP offers a feature-rich environment for WooCommerce stores that need flexibility. Its modular design allows store owners to enable only the WooCommerce features they need, helping balance customization with performance as the store grows.

Explore OceanWP →

Blocksy

Top Tip: Review how Blocksy’s layout controls interact with WooCommerce product grids before customizing further.

WooCommerce compatibility and templates

Blocksy includes built-in support for WooCommerce and applies consistent styling to core store templates, including shop archives, single product pages, cart, checkout, and account areas. Its integration aligns with WooCommerce’s default templating system, enabling store pages to function correctly without manual overrides.

Notable features in the free version

The free version offers responsive layouts, basic WooCommerce styling, and customization options via the WordPress Customizer. These controls help configure fundamental aspects of store presentation without requiring premium upgrades.

Performance and scalability

Blocksy is designed with performance in mind, using clean, modern code and modular features that can be enabled or disabled as needed. This helps maintain speed as product catalogs and store complexity grow.

Customization and layout control

Customization is handled through the WordPress Customizer, allowing adjustments to layout, colors, typography, and WooCommerce page settings. Blocksy’s controls provide a balance of flexibility and simplicity for store design.

Pros and cons

Blocksy’s strengths include flexible layout options and straightforward customization for WooCommerce stores. Its main limitation is that some advanced controls and features are only available through the premium extension.

Pro pricing overview

Blocksy is available as a free theme with optional premium upgrades that unlock additional WooCommerce customization, header layouts, and advanced design options. Pricing depends on the selected license and feature set.

• Blocksy: Free version available
• Blocksy Pro: Paid plans starting from $69 per year, with lifetime licensing options available

Header and archive controls for stores

Blocksy provides additional control over header layouts and product archive presentation, which can help shape navigation and browsing experiences for WooCommerce catalogs.

Blocksy provides advanced layout and styling controls that translate well to WooCommerce stores. Its theme-level WooCommerce options help maintain consistency across shop and product pages, reducing the need for per-page customization.

Explore Blocksy →

Kadence

Top Tip: Check how Kadence’s global style controls apply across your WooCommerce product and category pages before customizing deeply.

WooCommerce compatibility and templates

Kadence includes native support for WooCommerce, applying its design system to core store templates such as shop archives, single product pages, cart, and checkout. The theme’s structure follows WooCommerce’s default template hierarchy, helping store pages render consistently across devices.

Notable features in the free version

The free version of Kadence offers responsive layouts, basic store styling options, and control over typography and colors through the WordPress Customizer. These tools allow store owners to align store appearance with brand identity without additional plugins.

Performance and scalability

Kadence focuses on a lightweight codebase and efficient asset loading, which supports performance as your WooCommerce store grows with more products and content. This design helps maintain responsiveness over standard WooCommerce pages.

Customization and layout control

Customization is available via the Customizer, where users can adjust layout settings, colors, typography, and WooCommerce-specific design options. This setup provides a blend of global design control with WooCommerce page styling.

Pros and cons

Kadence’s strengths include clear global design controls and WooCommerce support. Its limitations are that deeper store layout customizations and advanced design options are generally part of premium add-ons.

Pro pricing overview

Kadence is available as a free theme, with premium extensions that unlock additional WooCommerce layout options, header designs, and global styling features. Pricing varies based on the chosen plan.

• Kadence: Free version available
• Kadence Pro: Paid plans starting from $69 per year, with bundle options available

Global design controls that speed up builds

Kadence includes built-in global palettes and typography systems, making it easier to maintain consistent styling across WooCommerce and non-store pages without repetitive adjustments.

Kadence combines structured WooCommerce templates with strong global styling controls. This makes it easier to manage consistent design across shop, product, and archive pages while supporting scalable store growth.

Explore Kadence →

Envo Royal

Top Tip: Test Envo Royal with a few common WooCommerce extensions to confirm layout consistency across shop and product pages.

WooCommerce compatibility and templates

Envo Royal includes built-in compatibility with WooCommerce and applies its styling to core store templates such as shop archives, single product pages, cart, and checkout. It relies on WooCommerce’s standard template structure, allowing store pages to function correctly without custom overrides.

Notable features in the free version

The free version of Envo Royal provides responsive layouts, basic WooCommerce styling, and support for popular page builders. It is designed to offer a ready-to-use storefront layout that can be adjusted through standard WordPress customization tools.

Performance and scalability

Envo Royal follows a lightweight approach intended to support reasonable performance for small to medium WooCommerce stores. Its structure is suitable for expanding product catalogs when paired with well-optimized plugins.

Customization and layout control

Customization options are available through the WordPress Customizer, where users can adjust layout settings, colors, and typography. Envo Royal also works with common WooCommerce extensions, including wishlist functionality provided by plugins such as
YITH WooCommerce Wishlist.

Pros and cons

Envo Royal offers a straightforward setup and WooCommerce compatibility suitable for quick store launches. Its main limitation is that deeper ecommerce-specific controls and advanced layout options are typically handled through plugins rather than the theme itself.

Pro pricing overview

Envo Royal is available as a free theme from the WordPress.org directory. Premium upgrades and related extensions are offered separately by the theme developer to expand layout and customization options.

• Envo Royal: Free version available
• Envo Royal Pro: Paid plans starting from $49 per year, with lifetime licensing options available

Product and shop layout strengths

The theme provides clean product listings and readable shop layouts, making it suitable for stores that want a simple, modern presentation without heavy configuration.

Envo Royal is a WooCommerce-oriented theme designed for quick store setup and modern storefront presentation. It includes layouts tailored for online shops, making it suitable for store owners who want a ready-made look with minimal configuration.

Explore Envo Royal →

Zakra

Top Tip: Review Zakra’s starter layouts with WooCommerce enabled to confirm how product grids and category pages scale on mobile.

WooCommerce compatibility and templates

Zakra supports WooCommerce and applies theme styling to core store templates, including shop archives, single product pages, cart, checkout, and customer account areas. It follows WooCommerce’s standard template structure, allowing store pages to render consistently without custom overrides.

Notable features in the free version

The free version of Zakra includes responsive layouts, WooCommerce compatibility, and multiple starter templates that can be adapted for online stores. These templates provide a practical starting point for launching a shop using default WooCommerce functionality.

Performance and scalability

Zakra is built with a lightweight approach intended to support fast load times and stable behavior as product catalogs grow. Its structure is suitable for small to medium WooCommerce stores that prioritize performance and simplicity.

Customization and layout control

Customization is handled through the WordPress Customizer, where users can adjust layout width, colors, typography, and general styling. WooCommerce pages inherit these global settings to maintain visual consistency across the site.

Pros and cons

Zakra offers flexibility through starter templates and reliable WooCommerce support. A limitation is that advanced store layout controls and deeper customization options are typically part of premium upgrades.

Pro pricing overview

Zakra is available as a free theme from WordPress.org, with optional premium plans that unlock additional layout options, advanced customization settings, and extended design controls.

• Zakra: Free version available
• Zakra Pro: Paid plans starting from $69 per year, with lifetime licensing options available

Best starting layouts for stores

Zakra’s WooCommerce-ready starter templates make it a solid choice for store owners who want a flexible base that can be customized gradually as store requirements evolve.

Zakra offers flexible starter layouts that include WooCommerce-ready designs. It provides a solid starting point for online stores that want structured templates first, with the option to refine layouts as the business evolves.

Explore Zakra →

Stockist

Top Tip: Review Stockist’s default product and shop layouts before customization to understand how it structures product presentation.

WooCommerce compatibility and templates

Stockist supports WooCommerce and applies theme styling to core store templates, including shop archives, single product pages, cart, checkout, and customer account areas. It follows WooCommerce’s standard template structure, allowing store pages to render consistently without relying on custom overrides.

Notable features in the free version

The free version of Stockist includes WooCommerce compatibility, responsive layouts, and a clean visual baseline designed for product-focused stores. It provides a usable foundation for launching an online shop using default WooCommerce functionality without unnecessary complexity.

Performance and scalability

Recent updates to Stockist have focused on improving performance and simplifying theme structure. The current version adopts a more lightweight approach, helping stores remain responsive as product catalogs grow and additional WooCommerce features are introduced.

Customization and layout control

Customization is managed through the WordPress Customizer, where users can control layout settings, typography, and general styling. WooCommerce templates inherit these global settings to maintain visual consistency across shop and product pages.

Pros and cons

Stockist offers clean presentation, improved performance, and practical WooCommerce defaults. As a newer iteration of the theme, it does not yet have the same long-term adoption history as some established options, which may matter to users who prioritize large user bases.

Pro pricing overview

Stockist is available as a free theme from WordPress.org, with a Pro version offered as a premium upgrade that expands layout options and styling controls.

• Stockist: Free version available
• Stockist Pro: Paid plans starting from $40 per year, with lifetime licensing options available

Best starting layouts for stores

Stockist includes WooCommerce-ready starter layouts designed to support clear product presentation and straightforward store structures. These layouts provide a practical starting point for stores that want a modern look without heavy configuration.

Stockist is a solid option for store owners who value clarity, performance, and a contemporary design baseline, and who are comfortable working with a newer theme that has been refined to meet current WooCommerce standards.

Explore Stockist →

Inspiro

Top Tip: Validate Inspiro’s WooCommerce pages with your actual products to ensure spacing and readability match your catalog.

WooCommerce compatibility and templates

Inspiro supports WooCommerce and applies theme styling to core store templates, including shop archives, single product pages, cart, checkout, and customer account areas. It works within WooCommerce’s standard template hierarchy, allowing store pages to display consistently without custom overrides.

Notable features in the free version

The free version of Inspiro includes responsive layouts, WooCommerce compatibility, and basic customization options through the WordPress Customizer. It provides a clean foundation suitable for launching a small to medium online store.

Performance and scalability

Inspiro is built with a lightweight structure designed to support reasonable performance across standard WooCommerce pages. Its layout approach helps maintain usability as product listings and content grow.

Customization and layout control

Customization is handled through the WordPress Customizer, where users can adjust colors, typography, layout width, and general styling. WooCommerce pages inherit these global settings to maintain visual consistency across the site.

Pros and cons

Inspiro’s strengths include a modern visual style, straightforward setup, and reliable WooCommerce support. Its main limitation is that advanced store layout controls and deeper ecommerce customization are reserved for premium upgrades.

Pro pricing overview

Inspiro is available as a free theme from WordPress.org. Optional premium plans unlock additional customization options, advanced layouts, and extended design features.

• Inspiro: Free version available
• Inspiro Pro: Paid plans starting from $69 per year, with lifetime licensing options available

Best use cases for small stores

Inspiro is well suited for small businesses and content-driven sites that want to add WooCommerce without complex store requirements. It works best for shops that value clean presentation and simplicity over extensive ecommerce controls.

Inspiro provides a modern, approachable design that works well for small to medium WooCommerce stores. It offers clear layouts for products and shop pages, helping businesses present offerings in a straightforward and professional way.

Explore Inspiro →

What Really Differentiates These WooCommerce Themes

All themes included in this guide meet a baseline level of quality for WooCommerce. They follow established WordPress and WooCommerce best practices, provide reliable template structures, and deliver solid performance under normal store conditions.

The main differences lie in how each theme approaches customization. Some offer more layout and styling control at the theme level through the WordPress Customizer, while others intentionally remain lean and neutral, leaving most design decisions to page builders or custom styling.

These differences are largely about workflow preference rather than capability. Implementation details vary from theme to theme, but for most store owners, what matters is how much control is available out of the box versus how much is delegated to page builders.

The best choice is the one that matches your preferred balance between built-in theme controls and external design tools, while keeping WooCommerce pages stable and easy to maintain over time.

Conclusion

Top Tip: If two themes feel comparable, choose the one that keeps WooCommerce templates easiest to manage over time.

Choosing the best WooCommerce WordPress theme in 2026 is primarily about how reliably a theme supports core store functionality. Across this guide, themes were assessed on how they handle WooCommerce templates, how consistently shop, product, cart, and checkout pages render, and how well they hold up as stores expand.

Rather than relying on visual demos alone, this comparison emphasizes structural compatibility, performance foundations, and predictable behavior across updates. These factors tend to matter more over time than surface-level styling, particularly as product catalogs grow and additional extensions, payment methods, or shipping logic are introduced.

Free themes available on WordPress.org remain a sensible starting point for most stores. They make it possible to validate real WooCommerce behavior early, using actual products and store pages, before committing to premium upgrades. Knowing when to upgrade is an important decision, especially when balancing layout flexibility against long-term stability.

If advanced layout control, global styling systems, or conversion-focused customization become part of your workflow, understanding upgrade paths and costs becomes essential. For a deeper comparison, see our guide on Elementor Free vs Pro, along with our breakdown of Elementor Pro pricing, plans, and value.

Ultimately, the right WooCommerce theme is one that supports your store’s needs today while remaining easy to maintain as those needs evolve. Start with a solid foundation, test using real store content, and make upgrade decisions based on clear requirements rather than feature lists.