The Scenario
You're a quant researcher and you've just finished a momentum strategy specification — RSI below 40 on an uptrend, confirmed by EMA crossover — that you want to backtest on a 13-coin crypto universe over the last 90 days. You have BTC, ETH, SOL, and 10 others in your Google Sheet. You need daily OHLCV for all 13 coins, plus the indicator values, in a structure your backtesting script can read directly.
The bad version:
- You pull OHLCV from a crypto data provider for BTC, export it, import it into your sheet, repeat for ETH, repeat for SOL — 13 times.
- Three of the coins have gaps in their OHLCV data because they were listed mid-period. Your script doesn't handle missing rows cleanly and throws an index error at row 47 every time you run it.
- The EMA and RSI you calculate in the sheet use generic formulas that don't account for the coin's first available date, so the early indicator values are wrong and your backtest is contaminated.
You're a researcher. This is infrastructure work, and it's eating your research time.
The Easy Way: One Prompt in SheetXAI
SheetXAI is an AI agent that lives inside your Google Sheet. It reads the crypto ticker list, calls the Polygon.io crypto aggregates and indicator APIs, and writes OHLCV data and indicator values into per-coin tabs — handling gaps and missing dates cleanly.
For each crypto ticker in column A, fetch 90 days of daily OHLCV bars from Polygon.io and write the data into a separate sheet tab named after each coin.
What You Get
- One tab per coin, labeled with the ticker (e.g., X:BTCUSD, X:ETHUSD).
- Columns: Date, Open, High, Low, Close, Volume — one row per trading day.
- Dates with no data (new listings, exchange downtime) are included as blank rows with a flag rather than silently omitted, so your script can handle them explicitly.
- All coins on the same 90-day date range for consistent cross-coin analysis.
What If the Data Is Not Quite Ready
I also need 14-day RSI and 20-day EMA for each coin written into the same tabs
Pull the 14-day RSI and 20-day EMA for all crypto tickers in column A from Polygon.io and write the results into columns B and C of my "Crypto Signals" sheet.
Three of my coins were listed fewer than 90 days ago and won't have the full history
For each crypto ticker in column A, fetch as much daily OHLCV data as available from Polygon.io going back up to 90 days. If a coin has less than 90 days of history, write what is available and add a note in the tab header indicating the first available date.
My ticker list uses CoinGecko IDs instead of Polygon.io format
The crypto tickers in column A use CoinGecko ID format (e.g., bitcoin, ethereum, solana). Convert each to the Polygon.io ticker format (X:BTCUSD, X:ETHUSD, X:SOLUSD) before fetching. Write 90 days of OHLCV into separate tabs using the Polygon.io format as the tab name.
Pull 90 days of OHLCV, calculate daily return for each coin, and identify the top 5 performers over the period
For each crypto ticker in column A, fetch 90 days of daily OHLCV from Polygon.io and write it into per-coin tabs. Then calculate the total return for each coin over the 90-day period as (last close minus first close) divided by first close. Write the results into a "Performance Summary" tab sorted by total return descending, and highlight the top 5 performers in green.
One prompt covers the data pull, the return calculation, and the ranked summary across all 13 coins.
Try It
Open a Google Sheet with your crypto tickers in column A and Get the 7-day free trial of SheetXAI. Ask it to fetch 90 days of OHLCV and indicator data from Polygon.io and structure it into per-coin tabs for your backtest. For technical indicators on an equity or forex watchlist, see the spoke on calculating RSI and EMA. For the full partner overview, see the Polygon.io hub.