Builder Codes

Implementation Logic

Builder codes enable developers who build alternative frontends for Extended to earn a builder fee on each trade they route for users. This fee goes 100% to the builder and is defined per-order. To enable builder codes, a builder must have an Extended account.

When a builder routes an order through their app or strategy, they include their clientId (available on the API page in the Extended UI) and a builderFee value:

builderId: 123,     // builder's clientId
builderFee: 0.0005  // fee fraction (0.0005 = 0.05%)

The maximum allowed builder fee can be fetched using the get_fees method — the TradingFeeModel includes the builder_fee_rate parameter.

There is no manual builder-fee claiming process. All builder fees are automatically transferred to the builder’s Extended account daily at 00:00 UTC.

You can find an example implementation in our Builder Order Example Code: link.

If a user qualifies for a trading rebate while using a builder code, they still receive that rebate. The builder-codes system fully supports Extended’s fee and rebate schedules.

Referrals & Builder Codes

If a user registers with a referral code, that code remains permanently linked to their account.

However, when the same user trades through a builder code, the builder code overrides the referral code for trades that include a builder fee. In those trades, the original referrer receives no commission, and only the builder receives the builder fee.

If the user trades directly via the Extended interface (that is, without a builder code), referral rewards and discounts still apply.

Referral-fee discounts apply only to non-builder orders. Trades routed through builder codes are not eligible for referral-based discounts.