How to Test an MT5 API Without Risking Real Money

You can build and test a whole MT5 integration without putting a cent at risk — if you test with the right thing. The safety comes from the account, not the API key. Use a broker demo account, and work up from reading to trading.

A test key is not a sandbox

Many APIs have a sandbox: test keys that hit a fake market. fxapis does not. Keys are labelled fx_live_ and fx_test_ so you can tell configurations apart, but both reach real brokers. A test key connected to a real-money account places real trades.

Brokers already run the best sandbox there is: demo accounts. They trade on real prices with play money, on servers built for the purpose.

Step 1: connect a demo account

Open a free MT5 demo account with your broker and note three things: the login, the password, and the demo server name — usually ending in -Demo. Then connect it:

curl -X POST https://api.fxapis.com/v1/accounts \
  -H "Authorization: Bearer $FXAPIS_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "login": "26177561", "server": "VantageMarkets-Demo",
        "password": "the-demo-password", "mode": "warm_on_demand",
        "label": "demo" }'

Bring it online with POST /v1/accounts/{id}/warm and poll GET /v1/accounts/{id}/status until the state is ready — about 10 seconds in our measurements. If it lands in invalid_credentials, check the server name first.

Step 2: read before you write

Make requests that cannot change anything:

curl https://api.fxapis.com/v1/accounts/$ACCOUNT_ID/positions -H "Authorization: Bearer $FXAPIS_KEY"
curl "https://api.fxapis.com/v1/accounts/$ACCOUNT_ID/symbols?search=EURUSD" -H "Authorization: Bearer $FXAPIS_KEY"

The second shows how your broker names the symbol and its volume rules (volumeMin, volumeStep). If you want to know an order will pass the margin check, POST /v1/accounts/{id}/calculate answers without opening anything.

Step 3: place the smallest order

Send the minimum volume, with an idempotency key:

curl -X POST https://api.fxapis.com/v1/accounts/$ACCOUNT_ID/orders/market \
  -H "Authorization: Bearer $FXAPIS_KEY" \
  -H "Idempotency-Key: $(uuidgen)" \
  -H "Content-Type: application/json" \
  -d '{ "symbol": "EURUSD", "side": "buy", "volume": "0.01" }'

Note that the volume is a string, "0.01" — fxapis refuses JSON numbers so no size is rounded on the way.

Step 4: check what came back

Do not stop at a 201. Read the result:

• state should be filled, with a filledPrice and the broker's own order number.
• GET /v1/accounts/{id}/positions should now show the position.
• Close it with POST /v1/accounts/{id}/positions/{ticket}/close, again with an idempotency key, and check the position has gone.

Compare against what MetaTrader shows for the demo account. Your integration is working when the two agree.

Step 5: test the failures on purpose

The happy path is the easy part. On the demo account, try:

Each failure should end where your code expects it to. The errors reference lists every code and whether to retry.

Going live

When the demo behaves, connect a live account and start with the smallest sizes. Keep separate keys for test and live configurations — the label makes a test key in production easy to spot — and keep the demo account for regression tests.

Next steps

• Quickstart — the same steps with Python and Node.js samples.
• Why an MT5 trade can fail — reading a rejection.
• Create your key and connect your first demo account.