How to build a portfolio tracker in Bubble

To build a portfolio tracker in Bubble, you create data types for a user’s assets, set up workflows that let users add or update holdings, and (optionally) pull live prices from an external API using the API Connector. The UI is just repeating groups showing each asset with totals calculated using Bubble’s built‑in expressions. The core is: a Holding data type linked to User, fields for quantity and symbol, and a workflow that recalculates value when prices update.

Core Data Structure

Create two data types: Holding and Price. A Holding stores what the user owns (ex: BTC, 2.1 units). A Price stores the latest market price you fetch from an API. Linking them allows Bubble to compute portfolio value on the fly using simple expressions.

• Holding fields: symbol (text), quantity (number), owner (User)
• Price fields: symbol (text), last_price (number), updated_at (date)

Adding & Updating Holdings

Create a form where users enter the asset symbol and quantity. A workflow runs on button click: Create a new Holding with those values and Current User as owner. To update, use Make changes to a thing and adjust quantity.

• Use a Repeating Group of Holdings filtered by Current User to show the portfolio.
• For total value: cell’s Holding quantity × Search for Price:first_item last_price.

Fetching Live Prices

Use the API Connector to call a real pricing API (for example, CoinGecko’s free price endpoint). Set it as Data type call so Bubble stores the response.

// Example CoinGecko price call
https://api.coingecko.com/api/v3/simple/price?ids=bitcoin,ethereum&vs_currencies=usd

Create a backend workflow that runs every few minutes: call the API, then Make changes to a list of Price so each symbol’s last\_price updates. Privacy rules should allow only admins or backend workflows to modify Price.

Displaying Portfolio Totals

Add text elements inside the Repeating Group like: Current cell’s Holding quantity × Parent group’s Price last\_price. For overall total, use a parent text: Search for Holdings (owner = Current User)’s sum of (quantity × related price). Use an Expression from the Toolbox plugin if you prefer custom math, but Bubble’s built‑in operators usually work.

Final Notes

Keep all price updates in backend workflows so the app remains fast. Use constraints in searches to avoid heavy database loads. With this structure, the portfolio tracker stays clean, scalable, and easy to extend (e.g., charts, categories, or transaction history).