Visual item set building app for League of Legends built with Ruby, Sinatra, MaterializeCSS and JQuery. Made for the Riot API Challenge 2.0.
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bildr is a HTML5 web application built with a Ruby and Sinatra back-end and a MaterializeCSS front-end. bildr was created to allow for easy and quick creation of item sets outside of the League of Legends client while providing more information than the client's item set builder, such as item efficiency statistics. This application was made as a submission for the Riot Games API Challenge 2.0.

The site can be viewed at

Short Demo Video Demo

Installation and Set-up

If you want to run the app locally.


  • Ruby
  • Bundler
  • A Riot Games API key


  1. First clone the repository with git clone
  2. Navigate to the cloned directory with cd item-set-builder/
  3. Run bundler to install the required Ruby gems with bundle install
  4. Set up a system environment variable named LOL_KEY and set it equal to your Riot Games API key. If you are using Windows, set the variable in Control Panel | System Properties | Environment Variables. If you are using Linux or OS X simply run export LOL_KEY=<YOUR API KEY>


  1. Start the application with ruby app.rb from the application's root directory
  2. The application can be viewed from any browser at localhost:4567

Features and Functionality

Upload Item Sets

bildr lets you use previously saved League of Legends item sets as templates or starting points for further item set customization. To use a previously created item set navigate to:

League of Legends\Config\Global\Recommended\

for global item sets. Or to:

League of Legends\Config\Champions\{championKey}\Recommended\

for a champion specific item set. bildr will automatically parse the JSON into visual, manipulable item blocks.

Download Item Sets

When you're done with your item set, you can download the item set by simply clicking the Download button in the navigation bar. When downloaded, the application will notify you where to place the completed item set, either to the global directory or champion-specific directory as listed above.

Saving to Browser Storage

If you are working on a item set in bildr but need to close your browser or restart your computer for some reason, the application gives you the option to save your in progress item set with the Save button.

Saving your item set works by utilizing the localStorage functionality of modern browsers. If for some reason you neeed to clear your saved item set, simply hit Reset and then Save.

(Note: you can only have one item set saved at a time and clicking Save will overwrite any previously saved item set)

To retrieve your saved item set, simple navigate to and your set should automatically load!

Reset Item Set

Item sets that you are currently working with can be completely reset by clicking the Reset button in the horizontal menu bar. Note that this will reset all items in the item block viewer as well as information in the Set Info tab. Also note that there is no way to recover your item set after you have hit reset unless you have saved your item set as Reset does not reset your saved item set.

Item Block Manipulation

Item Block Controls

In the item block manipulation panel, the user has four possible ways to manipulate item sets:

  1. Expand and collapse the item blocks
  2. Rename the item blocks
  3. Create new item blocks
  4. Delete existing item blocks

Item blocks are simply extensions of the MaterializeCSS collapsible object and have all the functionality of these constructs.

Item Selection and Drag-and-Drop

Selecting items is as simple as picking them from the All Items tab in the left-side menu and dropping them into an open item slot. bildr supports dropping items into filled item slots by pushing all items down or stacking where applicable. Furthermore, bildr follows the League of Legends stacking rules, with no more than five health or mana potions, three stealth wards, and two vision wards.

In order to help find the items you want, bildr incorporates the filtering system found in the League of Legends item shop, with support for filtering by multiple stats and searching for specific stats in the search bar.

The drag-and-drop functionality built in to bildr utilizes the HTML5 standard for drag-and-drop, and as such supports a wide variety of browsers. Unfortunately, mobile browsers are not supported at this time.

In addition to all the information found in the League of Legends shop being available in tooltips over each item, the tooltips also include information on gold efficiency where applicable. The item data is taken from the League of Legends static-data API endpoint with item images taken from Data Dragon. The information for item efficiency is parsed into a usable JSON format with Ruby scripts from a fan-made spreadsheet and merged into a single file with the data from the Riot Games API.

Item Set Info and Properties

In the Set Info tab of the left-side menu, users can set the item set name, specific map and mode, and specific champion. Leaving the map and champion un-selected leaves the item set as global. Uploading and downloading the item set will incorporate this information in the JSON data.

Champion data is collected from the Riot Games static-data API endpoint with champion icon images taken from Data Dragon. Map images are screen-captured from the League of Legends client and cropped horizontally.

Item Set Presets

If you don't have any currently saved item sets to work with and don't want to start from scratch, **bildr lets you choose from a variety of presets to serve as starting points for your item set builds. These preset item sets can be chosen from the Presets tab in the left-side menu.

Starting Build Presets

The first kind of preset you can choose from is a preset starting build. Choose from Support AP, Support Melee, AD Carry, Mid Lane AP, Mid Lane AD, Jungle, Top Lane Tank, Top Lane AD, or Top Lane AP and have the appropriate items automatically placed into your item block viewer. These presets serve as a starting point for your item set, allowing you to jump straight into your core build items. Presets

The second kind of preset item sets is a full item set scraped from Inspired by RiotBlackrook's script and dustinblackman's Championify app, bildr includes a Ruby implementation of these popular scrapers. bildr lets you choose item sets by Most Frequent or Highest Winrate for all champions.

Set Summary

Another major feature of bildr is the Set Summary view that can be brought up by clicking the Set Summary button in the top navigation menu. The Set Summary view essentially compiles all individual item data for your build and includes total cost, total efficiency, and a distribution of item tags. The total efficiency display includes the lower and upper bounds for efficiency, as many items, stacking items in particular, can have a wide range of efficiencies. Set Summary allows you to compare similar builds by a variety of parameters such as efficiency and how many items each build contains of a particular type.


Jacob Nisnevich

Jason Yang



bildr isn’t endorsed by Riot Games and doesn’t reflect the views or opinions of Riot Games or anyone officially involved in producing or managing League of Legends. League of Legends and Riot Games are trademarks or registered trademarks of Riot Games, Inc. League of Legends © Riot Games, Inc.