Set up Alpaca paper trading

1 Create the Alpaca account

Go to alpaca.markets and sign up. Choose the paper-only option — an e-mail address is all you need.

For a paper-only account Alpaca asks for neither identity verification nor a deposit. It is open worldwide.

Once signed in, switch to the Paper Trading account in the upper-left corner of the dashboard.

2 Generate your paper API keys

Open the API keys section of the dashboard and generate a new key pair.

Write the Secret Key down straight away. Alpaca shows it exactly once and never again. If you lose it you have to generate a new pair — and the old one stops working.

Paper and live use separate key pairs. A live key will not work in paper mode, and the other way round.

3 Enter the keys in GridTraderPro

Open Settings → Brokers → Alpaca → Configure…

1. Fill in API Key and API Secret.
2. Leave “Paper Trading -- use your Alpaca PAPER keys” ticked. It is on by default.
3. Click Test Connection. On success the app reports Alpaca Paper OK with the account number — that confirms key, secret and the paper setting in one step.
4. Close with OK, then press Connect on the Brokers tab. The status then reads Connected · PAPER.

4 Point market data at Alpaca

Open Settings → Market Data and set Primary under Provider Priority to Alpaca.

This step is not optional: the broker connection on its own delivers no prices. Without it GridTraderPro reports that the Alpaca keys are missing.

What is different in paper mode

So that you do not trip over differences that are not faults:

• Prices come from the free IEX feed, not the consolidated SIP tape. They can therefore differ slightly from your broker’s quotes.
• Only market and limit orders, always day orders, and no trading outside regular market hours.
• Whole shares only — fractional shares are not supported.
• Short levels need a margin account at Alpaca and a shortable symbol.
• Order status is polled roughly every three seconds rather than streamed, so a fill can appear with a short delay.