Environments and API base URLs
B402 has two surfaces with different access models. Use the table that matches the endpoint you're calling.
Authenticated APIs — /papi/v2/b402/*
Used for /supported, /verify, and /settle. These require RSA-SHA256-signed requests with a registered clientId, accessToken, and IP-whitelisted source IP — see API request signing and Apply partner developer account.
| Environment | Chain | Chain ID | Base URL |
|---|---|---|---|
| Sandbox (Testnet) | BSC Testnet | 97 | Please contact us for access |
| Production | BSC Mainnet | 56 | Please contact us for access |
Why "contact us"? Production access requires merchant onboarding (clientId issuance, RSA public-key registration, source-IP whitelisting). The base URL is handed out together with these credentials so merchants don't accidentally point a sandbox-issued credential at production. Apply via Apply partner developer account.
All code examples in these docs use {BASE_URL} as a placeholder — substitute the value provided to you during onboarding. Endpoint paths append directly: {BASE_URL}/papi/v2/b402/supported.
Public discovery APIs — B402 Bazaar
Used for /bazaar/{resources, search, merchant} (the B402 Bazaar catalog). These are public, read-only, and require no authentication — any client can call them without a clientId or signature.
| Environment | Chain | Chain ID | Base URL |
|---|---|---|---|
| Sandbox (Testnet) | BSC Testnet | 97 | Please contact us for access |
| Production | BSC Mainnet | 56 | https://www.binance.com/bapi/ramp/v1/public/ramp/b402 |
The discovery base URL is stable and safe to hardcode in client SDKs. Discovery paths are documented on B402 Bazaar — Verifying your listing.
Note: Discovery responses are wrapped in Binance's standard BAPI envelope (
{code, message, messageDetail, data, success}); the CDP-compatible payload is indata. CDP-built client SDKs need to unwrap one extra layer compared to callingapi.cdp.coinbase.com/platform/v2/x402/discovery/*directly.
It is recommended to start with the Sandbox (Testnet) environment first. Once integration testing is complete, contact us for Production (BSC Mainnet) credentials.