Backend Technical Task

What they ask

After the HR interview, backend candidates (interns included) receive a technical task to complete at home before the technical interview. Tasks in this area look like, for example:

• Build a small service that ingests price ticks for a set of stock symbols (POST endpoint or a file), stores them, and exposes: the latest price per symbol, daily open/high/low/close per symbol, and a watchlist endpoint a user can add or remove symbols from. Include tests and a README.
• Implement a simplified order book: accept buy and sell limit orders, match them by price-time priority, and expose the resulting trades.

Language and framework are your choice; candidates reported using Node, Python and Go. The task is then discussed in the technical interview, where they ask why you structured it the way you did and what you would change under real load.

What they look for

• Clean project structure, clear separation between HTTP layer, domain logic and storage.
• Tests that cover the tricky parts (OHLC boundaries at midnight, duplicate ticks, removing a symbol not on the list).
• Correct money handling (integers or decimals, never floats) and idempotent writes; this is a brokerage.
• A README that explains how to run it and the trade-offs you chose, since the task is the seed for the next interview.