> For the complete documentation index, see [llms.txt](https://indexone.gitbook.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://indexone.gitbook.io/docs/product-guides/index-construction/how-to-use-custom-code-to-build-an-index.md).

# How to use custom code to build an index

## Step 1 - Click on "Index Builder"

<figure><img src="/files/w5jnvgNrPmYUSQUryfv2" alt=""><figcaption></figcaption></figure>

Navigate to ["Index Builder"](https://indexone.io/indexbuilder) to access the indexing platform.

## Step 2 - Click on "Use Custom Universe"

<figure><img src="/files/8u29767Zg97Mhxm8V1GV" alt=""><figcaption></figcaption></figure>

Click on "Use Custom Universe" to view all options on how you can upload your custom universe.

## Step 3 - Click on "Custom Code"

<figure><img src="/files/Hpfh0a3pGoPyaBqiaxg7" alt=""><figcaption></figcaption></figure>

Click on "Custom Code" and test your code.

**If you have a file you would like to upload instead...**\
\
Click on "Upload Universe" and select the file type that you would like to upload.

<figure><img src="/files/dRFwN1U5zNlUXUMGxCEe" alt=""><figcaption></figcaption></figure>

## Step 4 - Test your code

<figure><img src="/files/bYsDazN6FaMU09HhcsYN" alt=""><figcaption></figcaption></figure>

Test and save your code. Once you're happy with it, create the bactest of your custom index.

## Step 5 - Click "Create Backtest"

<figure><img src="/files/hWvX5onB62cOljiMHiX6" alt=""><figcaption></figcaption></figure>

Click "create backtest" to load a backtest of your index. A backtest usually takes between 1-3 minutes, depending on the number of data points being processed by the platform.

<figure><img src="/files/CXZJUE2Ox0xdwvxHA9Pn" alt=""><figcaption></figcaption></figure>

Once the backtest has loaded, you can view its index performance benchmarked against SPY (SPDR S\&P 500 ETF Trust) and VT (Vanguard Total World Stock Index Fund ETF), as well as other metrics such as rolling volatility, drawdown, total turnover and rebalance statistics.

## Step 6 - Launch your new index

<figure><img src="/files/Bkg4nQW8Bdgbw9wspLJg" alt=""><figcaption></figcaption></figure>

Navigate to the "Go Live" arrows on the top left corner to name your new index, insert a description of the index, set calculation frequency, timezones, start/end time and visibility of the index (Public, Team Visible or Private).&#x20;

Once you've filled out the details of your index, click "Launch."

<figure><img src="/files/y3I8OVE2nXgJ0eVTqgRF" alt=""><figcaption></figcaption></figure>

It's as easy as that. Find out how you can build your own index on Index One's [index builder](https://indexone.io/indexbuilder).


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