Understanding RPI Orders
Q: What is an RPI (Retail Price Improvement) order?
A: An RPI order is a special Maker order placed by API Traders on the MAX exchange, specifically designed to enhance the trading experience for individual users.
RPI orders are exclusively matched with Taker orders placed by individual users (via the App or Web) and will not be matched against other API trading bots. This design aims to fully protect the trading interests of individual users. By effectively preventing front-running by high-frequency trading and bots, it further narrows the market bid-ask spread and ensures that real users' orders are executed smoothly at better prices.
Q: What is the difference between RPI orders and standard orders?
A: RPI orders function identically to standard Maker orders, but with a few key differences:
| Feature | Standard Maker Order | RPI Order |
| Counterparty | All Taker orders (including API) | individual user Taker orders only |
| Placement Method | App, Web, and API supported | API only (UI not supported) |
| Order Priority | Price-time priority | Lowest priority at the same price level |
| Conditional Orders | Can be combined with Stop-Loss/Take-Profit | Cannot be combined with conditional orders |
Q: How do I benefit from RPI orders
A: As an Individual User:Benefits apply automatically without any extra steps:
。Better Prices:RPI liquidity is reserved for you, allowing your orders to fill at tighter spreads.
A: As an API Trader:RPI orders only execute against individual users:
。Built-in Protection:Individual user flow is typically healthier. Your RPI orders avoid high-frequency bots and only match with higher-quality orders.
Understanding RPI OrdersOrder Eligibility and Placement Methods
API Placement Only: RPI orders can only be placed via OpenAPI. To place an order, use the v3 API with ord_type set to 'rpi'.
Q: Can I place RPI orders on the App or Web?
A: No. RPI orders can only be placed via the API. Currently, placing RPI orders through the App or website is not supported.
Q: Which API users can place RPI orders?
A: All API Traders can place RPI orders without any special application. They can only be placed via OpenAPI using the RPI order type; the App, Web interfaces, and conditional orders are not supported.
Q: What are the benefits of placing RPI orders for API Traders?
A: The core value of an RPI order is that it 'guarantees the counterparty is a real individual users (Taker),' as the system actively prevents matching against other algorithms or API trading bots. For market makers and liquidity providers, this offers three substantial benefits:
- Higher Quality Fills: Retail orders generally lack arbitrage intent, effectively reducing post-trade inventory risk.
- More Stable Order Flow: Within the retail liquidity pool, the quality of order flow is much more predictable compared to the general public order book.
- No Additional Fees: The fee rate for RPI orders is identical to standard Maker orders (calculated based on your current VIP tier), incurring no extra costs.
Q: Can RPI orders be combined with Stop-Loss or Take-Profit orders?
A: No. RPI orders cannot be used in combination with conditional orders (including Stop-Loss, Take-Profit, or Stop-Limit orders). This is a system-level limitation, not a functional error.
Matching Rules
Q: What is the execution priority for RPI orders?
A: RPI orders have the lowest priority among all orders at the same price level.
The system's matching logic is as follows:
- Priority Execution: If there are standard (non-RPI) Maker orders at the same price point, the system will execute those orders first.
- Subsequent Execution: RPI orders will only be matched after all non-RPI orders at that price level are fully filled.
This means RPI orders act as a 'passive liquidity provision' mechanism and will not take away execution opportunities from standard Maker orders.
Q: Which orders can match with RPI orders?
A: Eligible to match:
- Retail App / Web Taker Orders: Market orders (Takers) placed by individual users. via the mobile App or Web interface. These are the exclusive counterparties for RPI orders.
Ineligible to match:
- API Trader Taker Orders: Taker orders executed automatically via API will not match with RPI orders.
- Other RPI Orders: Two RPI orders cannot be matched against each other.
Q: What are 'crossed orders'? Why do the trade history and order book sometimes look unusual?
A: 'Price crossing' refers to a situation where the bid price of an RPI order is higher than the ask price, or the ask price is lower than the bid price (because RPI orders cannot match with each other, nor can they match with standard API orders).
When this occurs:
- Hidden from Order Book: The system will hide these crossed RPI orders from the order book interface to maintain a clean and organized display.
- Active in Matching Engine: These orders remain active within the matching engine; they are simply hidden and will not be automatically canceled.
- Execution Behavior: When a individual user's order matches with an RPI order, it may result in an execution price that appears to cross or bypass existing API orders.
Trade Anomalies and Order Placement Recommendations
Q: Is it normal that some orders are invisible on the order book but still affect my executions?
A: Yes, this is normal. When two RPI orders become 'crossed' (the bid price exceeds the ask price), the system hides them from the order book interface. However, these orders remain active within the matching engine and can be executed normally.
Therefore, you may encounter resting orders that are 'invisible' on the order book but actually exist in the system. This is not a system error, but rather an intended design of the RPI mechanism.
Q: Why did my limit order execute as a Taker when there were no visible resting orders on the order book?
A: This can happen. When two RPI orders become 'crossed' (the bid price exceeds the ask price), the system hides them from the interface. However, they remain active within the matching engine and can be executed normally.
If you place a limit order assuming the order book is empty at that price level, your order may execute as a Taker against one of these hidden RPI orders.
Recommendation: If you want to guarantee that your order is posted as a Maker, you can use the Post-Only order mode (see the following question for details).
Q: What is Post-Only? Why is it recommended to use alongside RPI orders?
A:Post-Only is an order mode that ensures your order is strictly posted to the order book as a Maker. If the order would execute immediately upon placement (for instance, by matching against an existing RPI order), the system will automatically cancel it rather than executing it and charging you a Taker fee.
Benefits of using Post-Only in an environment with RPI orders:
- Prevents unexpected Taker executions: Avoids immediate fills caused by hidden RPI orders.
- Guarantees Maker fees:** Ensures your order is always subject to Maker fee rates.
- Strict cost control:** Especially crucial for traders who want precise control over their trading fees.
Note: If a Post-Only order cannot be posted as a Maker, it will automatically cancel and not execute. Please ensure your price settings are appropriate to prevent your orders from being repeatedly canceled.
Fees
Q: Are the fees for RPI orders the same as standard Maker orders?
A: Yes. Currently, the trading fees for RPI orders are identical to those of standard Maker orders. They are calculated based on your account's VIP tier, incurring no extra charges and offering no additional discounts. The company reserves the right to adjust this fee structure in the future.
Q: Are there any additional fees for retail orders when matching with RPI orders?
A: No. If a Taker order placed by a individual users via the App or Web matches with an RPI order, the fee calculation is exactly the same as a standard Taker execution. There are no extra charges.
The key highlight of RPI orders is 'zero disruption for individual users.' This underlying mechanism operates completely in the background, allowing general users to naturally benefit from better market prices and deeper liquidity without noticing any difference in their trading experience.