How to Connect to the Binance Prediction Market API? From Authorization to Settlement Verification

Binance

23 October 2026

The challenge of connecting to the Binance Prediction Market API isn't writing code. It's about two things: whether you hold a Binance Wallet in a supported region, and whether you know this API belongs to the Web3 Wallet product line, not Binance Exchange's Spot/Futures API. Its authorization process has one more layer than a regular Binance API Key: besides the Prediction Trading permission on your API Key, placing orders and transferring funds also require enabling SAS (Secure Auto-Signing) in the Binance App. Otherwise, the API returns error -31003.

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Below, we break it down into three stages: authorization, order placement, and settlement verification. If you cannot find the "Prediction Market" entry in your Binance App, it means the feature is unavailable in your current region or account status, and there is no need to attempt the following steps.

Authorization: All Three Layers Are Necessary

The first layer is the Prediction Account and SAS. Enter the Prediction Market in the Binance App and complete the prediction account creation. Then go to [Assets] → [Prediction] → [Settings] and enable Secure Auto-Signing (SAS). SAS allows API-initiated order requests to be authorized on-chain. Without it, endpoints like place order and transfer/inbound will be directly rejected.

The second layer is API Key permissions. Create a key on the Binance website under [Account] → [API Management], and check Prediction Trading under API Restrictions. This is a standard step, but an easy thing to miss is that the Prediction Market API uses the /sapi/v1/w3w/wallet/prediction/ path, which is a different system from the Spot API's /api/v3/. Do not use Spot API signature examples for Prediction Market endpoints.

The third layer is when SAS authorization actually triggers. Read-only interfaces like checking market data or positions only require an API Key signature. However, place order, batch-cancel, and transfer/inbound require SAS authorization. If you find that read-only interfaces work but order placement fails during testing, first check whether SAS is enabled before digging into the signature algorithm.

Order Placement and Settlement: `quoteId` is Core, Don't Skip It

The order flow for the Prediction Market is quote first, then order. You cannot directly submit an order. GET /sapi/v1/w3w/wallet/prediction/trade/get-quote returns a quoteId, which you must include when calling POST .../trade/place. For market orders, timeInForce must be FOK. For limit orders, use GTC. Do not create combined values like LIMIT_GTC yourself, as this will cause a parameter error.

There is a common pitfall during the quoting stage: the unit for amountIn is wei (18 decimal places). 1 USDT must be written as 1000000000000000000. The minimum amount for a market order is approximately 1.5 USDT, but this value fluctuates with market depth. The documentation says "approximately," not a fixed threshold. Limit orders are not subject to this minimum amount constraint.

Fund deduction depends on fundingSource, not accountType. These two fields are easily confused: accountType determines the settlement/reference account (SPOT or FUNDING), while fundingSource determines which balance is actually debited (MPC or CEX, defaulting to MPC). If you find the deduction account differs from your expectation, check fundingSource rather than accountType.

Settlement verification has two paths: polling or WebSocket. After an order is filled, the positionStatus and canClaim fields returned by GET /sapi/v1/w3w/wallet/prediction/position can determine whether a position is ready to claim earnings. A more timely method is to subscribe to WebSocket pushes, with topics including web3_prediction_pm_claim_success, pm_claim_fail, pm_market_close, etc. Note that the pushed data field is a stringified JSON and requires a second JSON.parse. You cannot treat the outer envelope as an object after parsing it once. Also, the amount field only keeps two decimal places (truncated downwards), and values less than 0.01 are displayed as <0.01. Do not use this field for precise calculations; for exact values, query the REST API again.

A Publicly Known Signature Pitfall

The batch cancel endpoint batch-cancel uses indexed bracket parameters (e.g., cancelInfoList[0].orderId). Binance's server validates signatures against the original unencoded string, but mainstream HTTP libraries like Python requests, Java HttpURLConnection, Go net/url, and Node url automatically encode [ as %5B and ] as %5D. This causes a signature mismatch and returns error -1022 Signature for this request is not valid. Postman is unaffected because it does not encode keys. The official workaround is to use low-level HTTP APIs to manually construct the request body: Python uses http.client, Java writes raw body bytes directly, and Go uses strings.NewReader instead of url.Values.Encode(). If you are only connecting market data and single order placement, you won't encounter this issue for now; but if you are doing batch cancellation or grid-like strategies, this must be handled.

Regional Restrictions Are a Hard Barrier

The Prediction Market API is only available to eligible users, and actual availability depends on local regulatory and compliance requirements. Binance Wallet services are provided by Binance Barbados Limited and are not regulated by the ADGM entity or FSRA. The announcement explicitly states it is "not available to Hong Kong residents." If you cannot see the Prediction Market entry in the App, or cannot find the Prediction Trading permission option in API Management, it means your current account is not eligible. Reading documentation or adjusting signatures will not change this result.