Alpaca
United States. A key ID and a secret from Alpaca's dashboard; a paper account works the same way with its own pair.
Where the keys come from
In Alpaca's dashboard, under API keys, generate a key. Alpaca shows a key ID and a secret once; copy both. A paper-trading account has its own dashboard and its own pair, and the desk needs to know which kind it is, so switch Paper account on for a paper pair.
On Settings
Pick Alpaca · United States under Your broker, paste the key ID and the secret, set Paper if it applies, and click Save and connect. The desk asks Alpaca for the account and the positions at once and says how many holdings it found. A wrong pair, or Paper set the wrong way, comes back as "Alpaca did not accept these keys" with the reason.
What Desk · Home shows
Every position with quantity, average cost, the live mark, value, profit since cost and the day's move; cash and buying power. Alpaca hands out a current price for each position, and where it does not the desk marks the line from Yahoo. Watch · Home quotes through Yahoo, the US way, and the status dot follows US hours.
What it does not show
No futures, no options tape, no margin bar: Alpaca's read for individuals does not serve them, so those panels stay out of the way. The options tape on US names is on the Flow screen for every reader, from CBOE.
Read-only
The desk reads the account and the positions and nothing else. Alpaca keys can trade, so treat the pair like a password: it sits in the settings file on your computer and the desk never shows it back.