Thirty markets, one portfolio number

A Counter-Strike inventory can have a price on dozens of markets at once. Those numbers are not interchangeable: sources format items differently and make different assumptions about price and fees.

CSVault started with a product question rather than a chart question: what number is useful when someone wants to understand the collection they already own?

Keep source differences out of the interface

I chose to normalize market data behind one pricing layer. The portfolio view should not need a separate branch for every source, and a filter should not change behavior because one marketplace named an item differently.

That boundary lets the interface stay focused on the jobs a trader actually came to do: scan the collection, find a skin, compare positions, and maintain a wishlist.

Read-only means read-only

Steam sign-in exists to identify the inventory, not to request trade authority. Keeping that permission narrow was both a security decision and a product decision. The value of the tool is portfolio visibility; trade access would add risk without helping that job.

What I would measure next

The live product proves the workflow, but the next useful evidence is behavioral: how quickly someone can locate an item, how often filters are used, and whether the normalized view replaces a spreadsheet for repeat visitors.

The main design decision remains intentionally boring. Normalize the messy inputs once, then let the product speak in one consistent language.