Countdown Timer, Stock bar & timer, Social Proof, Cart reservation bar, Discount or Stock counter. Count down timer are extremely effective to generate scarcity to inspire visitors to purchase as soon as possible before a product becomes unavailable. Customize the look of your countdown timer by choosing from multiple styles and templates. Display immediately, after a set period of time, on a page’s bottom or top or below add to cart button. With Ultimate Scarcity Pro timer, you can develop and implement a wide range of scarcity building solutions with just a few clicks. Count down timer are extremely effective to generate scarcity to inspire visitors to purchase as soon as possible before a product becomes unavailable. Customize the look of your countdown timer by choosing from multiple styles and templates. Display immediately, after a set period of time, on a page’s bottom or top or below add to cart button. With Ultimate Scarcity Pro timer, you can develop and implement a wide range of scarcity building solutions with just a few clicks. more Countdown Timer - different types of countdown timer bar, Multiple templates. Stock bar & timer - Stock bar customization, Multiple font selection, etc. Social Proof - Display a widget on product detail page
Custom CSS Shopify Apps
Discover the best Custom CSS apps for your Shopify store in 2026. Compare features, pricing, and reviews to find the perfect solution.
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Show a sticky add to cart button on every product page and allow customers to checkout instantly! Boost your conversion rates with a Sticky Add to Cart! Our app adds a floating Add to Cart button on every product page, regardless of screen size. This makes it easy for customers to select products & streamline the checkout process. With a built-in countdown timer, our app creates a sense of urgency and drives more "Buy Now" clicks. No coding needed - our app works instantly on any store theme, with just one click. Install Sticky Add to Cart now and streamline your checkout process today! Boost your conversion rates with a Sticky Add to Cart! Our app adds a floating Add to Cart button on every product page, regardless of screen size. This makes it easy for customers to select products & streamline the checkout process. With a built-in countdown timer, our app creates a sense of urgency and drives more "Buy Now" clicks. No coding needed - our app works instantly on any store theme, with just one click. Install Sticky Add to Cart now and streamline your checkout process today! more Send customers directly to checkout! Fast checkout process by skipping the cart! Sticky Add to Cart button is visible on all product pages with just one click Increase buying urgency with a custom countdown timer to match your brand Add to cart button is visible on all devices types & screen sizes at all times Our Sticky ATC app supports tracking pixels for better retargeting campaigns
Increase diamond sales + slash time spent sourcing with AI curation that connects to your jewelry! Give your customers the ability to complete their diamond ring, pendant, or earring purchase on your website, all on their own! Our patented AI curation technology makes it easy. Also, use your Unbridaled powered Shopify site in-store to sell engagement rings with curated diamond options and eliminate decision overwhelm. Instead of taking weeks to close a sale, help them find their ideal diamond in minutes! Give your customers the ability to complete their diamond ring, pendant, or earring purchase on your website, all on their own! Our patented AI curation technology makes it easy. Also, use your Unbridaled powered Shopify site in-store to sell engagement rings with curated diamond options and eliminate decision overwhelm. Instead of taking weeks to close a sale, help them find their ideal diamond in minutes! more Connect your jewelry to certified diamond inventory Offer shoppers natural and/or lab grown diamonds with videos + certs to compare Intelligent curation makes it easy for your clients to decide on a diamond Intelligent pricing maximizes your profits while keeping prices competitive Integrates seamlessly with your Shopify theme and branding
Highly customizable sliding cart drawer with upsells, progress bar, unlockable free gifts and more. Unicart replaces your default cart page with a highly customizable sliding cart drawer. It offers upsells, cross sells, a dynamic sales progress bar, spend tiers to unlock free items, multi language support and more. Unicart can be completely customized to allow for all types of custom features and custom designs. It supports different design templates and you can schedule publish them anytime (Best for sales days). Unicart is developer friendly and can be customised to meet every requirement. Unicart replaces your default cart page with a highly customizable sliding cart drawer. It offers upsells, cross sells, a dynamic sales progress bar, spend tiers to unlock free items, multi language support and more. Unicart can be completely customized to allow for all types of custom features and custom designs. It supports different design templates and you can schedule publish them anytime (Best for sales days). Unicart is developer friendly and can be customised to meet every requirement. more Cross-sell and upsell by showcasing relevant products based on items in the cart Sales progress bar to motivate customers to spend more to unlock special rewards Allow customer's to unlock free items in their cart at specific spend tiers Access to completely customize the cart to your exact design and function needs Supports subscriptions, integrates with apps like PageFly, BOLD, Shogun and more
Cookie consent for GDPR, CCPA & LGPD. IAB TCF 2.3, Google & Microsoft certified. UniConsent simplifies GDPR, CCPA, LGPD, and COPPA compliance. Add a customizable cookie banner, manage user consent and data subject requests, and automatically scan and disclose the cookies on your store. As an IAB TCF 2.3, Google, and Microsoft UET certified CMP, UniConsent passes consent signals to your ad and analytics tags - protecting retargeting and conversion tracking while staying compliant. Built for e-commerce, publishers, SaaS, and marketing teams, in 52+ languages. UniConsent simplifies GDPR, CCPA, LGPD, and COPPA compliance. Add a customizable cookie banner, manage user consent and data subject requests, and automatically scan and disclose the cookies on your store. As an IAB TCF 2.3, Google, and Microsoft UET certified CMP, UniConsent passes consent signals to your ad and analytics tags - protecting retargeting and conversion tracking while staying compliant. Built for e-commerce, publishers, SaaS, and marketing teams, in 52+ languages. more Certified Google, Microsoft UET & IAB TCF 2.3 consent management platform Send IAB TCF 2.3 & Consent Mode signals to protect retargeting and ad revenue Fully customizable, multi-stage consent pop-ups and banners to match your brand Support for 52+ languages to reach a global audience Automatic cookie scanning and disclosure keeps your banner always up to date
Boost AOV with a Customizable Slide Cart Drawer, Smart Cross-Sells, Targeted Upsells & Gamification Unicorn is a powerful slide cart drawer app designed to drive more revenue for your store. A suite of powerful upsell tools to optimise your store’s Order Value (AOV) and conversion rates. With built-in upsell, cross-sell, and reward features, Unicorn turns every cart drawer interaction into an opportunity to delight customers and drive more sales. Built by ecommerce founders for ecommerce founders. Unicorn is a powerful slide cart drawer app designed to drive more revenue for your store. A suite of powerful upsell tools to optimise your store’s Order Value (AOV) and conversion rates. With built-in upsell, cross-sell, and reward features, Unicorn turns every cart drawer interaction into an opportunity to delight customers and drive more sales. Built by ecommerce founders for ecommerce founders. more Boost AOV with Targeted Upsells, Cross-sells, Upgrade to Subscription and more Increase Conversion: BOGO, Free Gifts and Stackable Discounts + Countdown timers Gamify Shopping with Tiered Rewards and Fully Customizable Progress Bars Create your own Shipping Protection Upsell as tick box or in the checkout button Fully customize & perfectly match your brand with an aesthetic Slide Cart Drawer
Upcart — custom slide cart with full design control to increase AOV and reduce cart abandonment Unlike basic cart drawer apps, Upcart turns your cart into a revenue-driving touchpoint with in-cart upsells, cross-sells, rewards, and add-ons—without redirecting shoppers or requiring multiple apps. Designed for fashion, food & beverage, beauty, and other DTC brands, Upcart matches your storefront and works seamlessly across desktop and mobile. Unlike basic cart drawer apps, Upcart turns your cart into a revenue-driving touchpoint with in-cart upsells, cross-sells, rewards, and add-ons—without redirecting shoppers or requiring multiple apps. Designed for fashion, food & beverage, beauty, and other DTC brands, Upcart matches your storefront and works seamlessly across desktop and mobile. more Increase AOV with in-cart upsells and cross-sells for frequently bought items Fully customize cart design with custom templates using HTML, CSS, and JSX Incentivize higher spend with rewards, progress bars, and free shipping goals Boost conversions with in-cart discounts and free gifts Reduce friction with a sticky slide cart that stays visible across your store
Set up a tax addon, dynamic surcharges, and a product surcharge. Easily add processing fees today. Our surcharge app helps you apply conditional fees, late fees, and automatic fees. Quickly add surcharge rules for a small order fee or one time fee. Manage checkout addons, dynamic addons, and free addons to collect an additional charge. Configure a payment surcharge, shipping surcharges, or a bottle deposit. Easily handle an order surcharge, rush fees, deposit fees, service fees, and checkout fees. Bill a membership fee, order & product fees, or a checkout surcharge. Our surcharge app helps you apply conditional fees, late fees, and automatic fees. Quickly add surcharge rules for a small order fee or one time fee. Manage checkout addons, dynamic addons, and free addons to collect an additional charge. Configure a payment surcharge, shipping surcharges, or a bottle deposit. Easily handle an order surcharge, rush fees, deposit fees, service fees, and checkout fees. Bill a membership fee, order & product fees, or a checkout surcharge. more Product fee, extra fee or cart fee — add price addons per item Credit card surcharge, payment method fee, cod fee or tariff surcharge Processing fee, handling fee and additional fees with deposits and fees Set a fee rule: advanced fees and checkout fee for any order Sync orders and fees directly to products or variants with fees payment
Show sticky add to cart buttons on your product pages. This increases sales and reduces abandonment. Allow your customers to quickly add to cart and buy your products. Lengthy product info can make add to cart buttons hard to find. However, a sticky add to cart is always highly visible. So your customers can buy now, add to cart and checkout faster. Our one click install saves time by adding a sticky add to cart that seamlessly integrates into your store. Use our built in reporting to easily see your sales increases and use with your Google Analytics and Facebook Pixel. Allow your customers to quickly add to cart and buy your products. Lengthy product info can make add to cart buttons hard to find. However, a sticky add to cart is always highly visible. So your customers can buy now, add to cart and checkout faster. Our one click install saves time by adding a sticky add to cart that seamlessly integrates into your store. Use our built in reporting to easily see your sales increases and use with your Google Analytics and Facebook Pixel. more Automatically match your store theme with high converting styles. Use our button Animator to attract more attention and 'move' the button. Display at the top or bottom and customize text. Visible and responsive to your customers on mobile, desktop & tablet. Unlimited impressions and clicks included.
Automatically price your customers' multiple uploaded files, images with various conditions. Meet the most advanced file upload app. Replace separate product options and order status apps with our all-in-one print on demand solution. Create targeted fields with strict file and dimension rules to prevent incorrect submissions (e.g DPI check). Calculate pricing dynamically based on file sizes(width, height, PDF page count) or custom forms. Manage production directly in the app. Create custom order statuses, send automated emails, and bulk download renamed files to stay organized. Meet the most advanced file upload app. Replace separate product options and order status apps with our all-in-one print on demand solution. Create targeted fields with strict file and dimension rules to prevent incorrect submissions (e.g DPI check). Calculate pricing dynamically based on file sizes(width, height, PDF page count) or custom forms. Manage production directly in the app. Create custom order statuses, send automated emails, and bulk download renamed files to stay organized. more Create upload fields with strict rules for file types, dimension (e.g DPI Check) Charge dynamic fees based on file sizes(e.g height) or custom form selections Automate file renaming and bulk downloads via built-in File Manager Track production with custom order statuses and auto email alerts (Shopify Flow) Charge dynamically based on inch square dimensions or PDF page counts etc.
Allow file uploads with orders and enable customers to edit images and create personalized products. Upload-Lift allows customers to upload files / images / photos on Product, Contact, Cart and Order Status pages. It's easy to set up and does not require any theme modifications. You can configure the allowed file types, and the app includes an image editor to let customers crop images in your desired format. Let customers upload photo upload on any page on your store. Upload-Lift allows customers to upload files / images / photos on Product, Contact, Cart and Order Status pages. It's easy to set up and does not require any theme modifications. You can configure the allowed file types, and the app includes an image editor to let customers crop images in your desired format. Let customers upload photo upload on any page on your store. more Fast upload of any file type up to 5GB in size. Image editor that allows cropping with predefined ratios and crop shapes. Preview of the uploaded image on the upload field and cart page. File Validations. Configure min/max file size and image dimensions. File conversion of advanced file formats e.g (PDF/Ai) into images.
Build trust with a stunning filterable & shoppable customer image gallery Build trust and increase conversions with a stunning shoppable & filterable customer image gallery, lookbook, photo gallery, product gallery, video gallery or portfolio gallery. Let customers upload photos, videos, tag multiple products, and inspire others to buy. Showcase customer photos on a product gallery automatically. Offer discounts for uploads, easily moderate content, import photos from Judge.me, Instagram and TikTok. Elevate your social trust, social proof, and product discovery. Build trust and increase conversions with a stunning shoppable & filterable customer image gallery, lookbook, photo gallery, product gallery, video gallery or portfolio gallery. Let customers upload photos, videos, tag multiple products, and inspire others to buy. Showcase customer photos on a product gallery automatically. Offer discounts for uploads, easily moderate content, import photos from Judge.me, Instagram and TikTok. Elevate your social trust, social proof, and product discovery. more Collect UGC - Customers upload images and videos directly on your gallery page Product gallery - Customers add relevant products on each gallery post Automatically display relevant images & videos on each product gallery Customers filter by products & custom fields to find what they're looking for Easily import existing content from Instagram feeds, TikTok and Judge.me
AOV+ with bundling, product addons, related products, cart page, checkout & post purchase upsell. High-conversion one click upsell & post purchase upsell app. Bundle frequently bought together products & addons to increase AOV. Use in cart upsell, cross sells & automatic product recommendations for complementary products on product page & cart drawer. Checkout upsell extensions & discount functions for bundling accessories. Mobile-responsive upsell funnel with thank you page & pop up upsell offers works with any theme to boost conversion rates in multi-language & multi-currency stores. High-conversion one click upsell & post purchase upsell app. Bundle frequently bought together products & addons to increase AOV. Use in cart upsell, cross sells & automatic product recommendations for complementary products on product page & cart drawer. Checkout upsell extensions & discount functions for bundling accessories. Mobile-responsive upsell funnel with thank you page & pop up upsell offers works with any theme to boost conversion rates in multi-language & multi-currency stores. more Show Amazon-style frequently bought together product upsell bundles on store Cross sell product add ons on product pages as list, grid, carousel or popup Pop-up a cart upsell funnel or display in-cart upsells in cart drawer & theme Display checkout upsells & post purchase page upsell with one click upsell Cross sell related products on thank you page & order status page after sale
Drive more sales with Meta Pixel integration, smart upsells, countdown timers, and low-stock alerts Supercharge your store with smart upsells, cross-sells, and post-purchase offers. Boost conversions with countdown timers, low-stock alerts, exclusive discounts, and flash sale campaigns. Track customer events with built-in Meta Pixel integration for better ad performance and insights. Personalize offers, increase average order value, reduce cart abandonment, and launch high-converting campaigns in minutes with an easy, no-code setup. Supercharge your store with smart upsells, cross-sells, and post-purchase offers. Boost conversions with countdown timers, low-stock alerts, exclusive discounts, and flash sale campaigns. Track customer events with built-in Meta Pixel integration for better ad performance and insights. Personalize offers, increase average order value, reduce cart abandonment, and launch high-converting campaigns in minutes with an easy, no-code setup. more Product page and In-Cart upsells with one-click add to order Post-purchase and Thankyou page upsells with one-click add to order Facebook Pixel for tracking website visitor actions and retargeting customers Countdown timers to create urgency for promotions Real-time inventory alerts for low-stock products
All In One Upsell app is designed to Boost Sales & AOV & encourage customers to buy more. The Essentialwolf Upsell & Cross Sell app is increase sales & AOV & user friendly with full customization tools for any business looking to increase their sales and AOV. Create highly targeted, personalized upsell funnels tailored to your customers’ preferences and spending habits—driving higher conversions and bigger sales. Plus, with real-time insights into customer behavior, you can easily track spending patterns and build even more effective upsell funnels. The Essentialwolf Upsell & Cross Sell app is increase sales & AOV & user friendly with full customization tools for any business looking to increase their sales and AOV. Create highly targeted, personalized upsell funnels tailored to your customers’ preferences and spending habits—driving higher conversions and bigger sales. Plus, with real-time insights into customer behavior, you can easily track spending patterns and build even more effective upsell funnels. more Display on product, cart, post-purchase, checkout and thanks you page. Support AI & Manual mode to personalized Upsell Funnel. Suggest related products to customers to increase the likelihood of a sale. Choose different types of layout and easy to customizable. In depth data analytics, track customer history, unlimited settings & many more.
Upsell Cart App to Improve AOV - Discounts, Free Shipping, Cross Sell & Quick Slide Cart Upsell cart helps you highlight additional products to customers as they add items to their cart which may increase your AOV. Our Quick Upsell app helps you turn every cart into a bigger sale — all before checkout. With features like upsell cart, popup cart & mini cart drawer, you can show smart product suggestions and irresistible discounts right when shoppers are most likely to buy. The cart widget makes it easy to add pre-purchase offers without interrupting the shopping flow. Upsell cart helps you highlight additional products to customers as they add items to their cart which may increase your AOV. Our Quick Upsell app helps you turn every cart into a bigger sale — all before checkout. With features like upsell cart, popup cart & mini cart drawer, you can show smart product suggestions and irresistible discounts right when shoppers are most likely to buy. The cart widget makes it easy to add pre-purchase offers without interrupting the shopping flow. more One-click upsells in the mini cart or popup cart to encourage bigger orders. Custom discounts that work with Shopify’s multiple discount combinations Pre-purchase upsell offers based on what’s already in the cart. Rewards Progress Bar: Motivate customers to spend more by showing spending goals Product recommendations using Shopify’s AI or your own chosen items.
Increase AOV and total revenue with upsell and cross-sell popups and targeted discount offers. Increase average order value using add to cart and checkout upsell popups shown to existing visitors at the right moment. Upsell Popup helps you grow revenue with small, high-impact wins like upsells, cross-sells, Buy One, Get One (BOGO), and discounts, without changing your checkout. Generate more revenue from exisiting traffic. Mobile-friendly design. No coding required. Match your store branding and launch in minutes. Easy to set up, backed by online support, and designed to pay for itself. Increase average order value using add to cart and checkout upsell popups shown to existing visitors at the right moment. Upsell Popup helps you grow revenue with small, high-impact wins like upsells, cross-sells, Buy One, Get One (BOGO), and discounts, without changing your checkout. Generate more revenue from exisiting traffic. Mobile-friendly design. No coding required. Match your store branding and launch in minutes. Easy to set up, backed by online support, and designed to pay for itself. more Trigger upsells on Add to Cart, Checkout CTA events, or ANY button click Use AI recommendations to suggest relevant products and raise Ave Order Value Generate more revenue by adding targeted discounts directly inside upsell popups Serve localised upsell popups with multi-language and currency support Increase conversions without slowing your store page speed or performance
Upsell effectively using AI: Automate in-cart upsells, checkout upsells & bundles to boost sales. Upsell Wizard transforms your sales with AI-driven upselling and cross-selling. Master in-cart upselling, checkout upsells, and post-purchase offers with ease. Boost your average order value through strategic upsell funnels, offering discounted upsells and 'buy x get y' deals. Enjoy hassle-free setup as Upsell Wizard's AI automates compelling product suggestions and upsell opportunities. Perfect for smooth, intelligent upselling. Questions? Our US-based support team is here to help. Upsell Wizard transforms your sales with AI-driven upselling and cross-selling. Master in-cart upselling, checkout upsells, and post-purchase offers with ease. Boost your average order value through strategic upsell funnels, offering discounted upsells and 'buy x get y' deals. Enjoy hassle-free setup as Upsell Wizard's AI automates compelling product suggestions and upsell opportunities. Perfect for smooth, intelligent upselling. Questions? Our US-based support team is here to help. more Upsell and cross sell related products, different variants, and bundles. Trigger upsell offers with specific variants, products, tags or collections. Supports "buy X get Y" discounts and free products. Translate everything your customers see into the language of your choosing. Built to work with Shopify's native discount system & new post-purchase flows.
Turn product pages and carts into honest upsells: bundles, BOGO, free gifts and cart goals. Upselly helps shoppers buy a little more — and feel good about it. Build bundles, quantity breaks, BOGO deals, free gifts and cart-goal rewards in minutes: pick a template, watch the live preview, publish. Every offer is a real Shopify discount applied automatically at checkout — no fake $0 products, no ads in your checkout, and we never take a cut of your sales. Offers speak your shopper's language too, with widgets translated into 12 languages. Pause an offer and it's gone instantly. Upselly helps shoppers buy a little more — and feel good about it. Build bundles, quantity breaks, BOGO deals, free gifts and cart-goal rewards in minutes: pick a template, watch the live preview, publish. Every offer is a real Shopify discount applied automatically at checkout — no fake $0 products, no ads in your checkout, and we never take a cut of your sales. Offers speak your shopper's language too, with widgets translated into 12 languages. Pause an offer and it's gone instantly. more Bundles & quantity breaks with real combined prices — buy more, save more BOGO & free gifts, added and discounted automatically at checkout Cart goal ladder: one progress bar for free shipping, gifts and discounts Frequently bought together cross-sells by product, tag, type or collection Widgets speak 12 languages and match your theme — you can override any label
Highly designed Image Slider can be displayed in the store! This application allows you to display a highly designed Image Slider in your store with no coding required; you can customize the speed at which the Image Slider flows, the number of pieces, the appearance of the arrows, and the type of animation. Bring a highly customizable Image Slider to your store. This application allows you to display a highly designed Image Slider in your store with no coding required; you can customize the speed at which the Image Slider flows, the number of pieces, the appearance of the arrows, and the type of animation. Bring a highly customizable Image Slider to your store. more Image Slider can be installed in your store. Customize the animation, speed, and design of the Image Slider. Separate images can be set for PCs and mobile.
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About Custom CSS Apps for Shopify
Custom CSS apps are essential tools for Shopify merchants looking to enhance their store's functionality and improve customer experience. These specialized applications help store owners streamline operations, increase sales, and provide better service to their customers.
When choosing a custom css app for your Shopify store, consider factors such as features, pricing, customer support, and compatibility with your theme and other apps. Reading reviews from other merchants can also provide valuable insights into the app's performance and reliability.
The apps listed on this page represent some of the best custom css solutions available in the Shopify App Store. Each has been selected based on its functionality, user ratings, and overall value for Shopify merchants.