Shopify custom theme — Happy Lights case study

About the project

About the business

A unique business model requires unique functionality, so the client contacted us to build a solution that would make it possible. It had to both make it easy for the customers to create and buy custom strings and keep the number of steps before the checkout as low as possible.

Challenges and solutions

From both the business and the technical point of view, the best solution was to create a new B2C Shopify store with a custom product builder functionality where all customizable product options could be set up on one page.

Custom product builders

  • Indoor light strings
  • Ceiling and table lamps
  • Outdoor light strings

The functionality of a builder is more or less the same for each product — there are just some minor differences with the types of cotton balls or the availability of the LED USB cord for some models.

Indoor light strings builder

1. Select the number of lights

2. Choose the cord

3. Choose the color

Picking colors manually

Customers need to select a ball on the interactive string, choose a color from the color palette and then repeat these two actions until all the balls on the string are colored.

This functionality makes it quick and easy to create a string of up to 50 unique lights in a unique order.


If the customer does not want to manually select the color for each ball, they can use the autofill functionality and choose colors for just 5 lights. After pressing the Autofill button, the whole string will be colored using the same pattern.

4. Additional services

The ceiling and table lamp builder

Customizing the cart

This solution which is crucial for the proper functioning of the store created yet another challenge. A typical Shopify cart consists of all products bought in a store, and when a color option of a light ball is set as a separate product, a standard Shopify cart, in this case, would be a total mess consisting of all the balls, cords, and plugs. This way, customers would feel that they are buying several random messy items instead of a single custom light string, which would make the customer experience in the store significantly worse. To fix this, we customized the cart, and now customers see just the final product they buy, not all its separate parts.

Calculating the price


To calculate the cost without VAT, the client was using a third-party app. Our task was to create and integrate into the product builder the functionality that would calculate the final price with the added VAT. This was challenging, but now the final price with and without VAT is automatically calculated right on the page and changes in real-time while the string is being customized.

Discount codes

Therefore, we had to build a complex development solution so that the discount codes could be applied to the cart, making it possible to buy one product for two different prices within the same store.


In the end, the client got the solution that solved their business challenges and fit their unique business model, making the shopping experience for their customers comfortable and fast. To see the client’s feedback about our work, please check the client review section in our Clutch profile.



A team of Shopify professionals, sharing the insights from a decade of Shopify hands-on experience.

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A team of Shopify professionals, sharing the insights from a decade of Shopify hands-on experience.