# Regions and connectivity Choose a Testnet API host, connect realtime and trade WebSockets, and keep connections reliable. Testnet is Polyester's public environment and runs the latest release. Mainnet is coming soon. Start with `https://api.testnet.polyester.com` for REST, ConnectRPC, and realtime access. Use the separate trade host for SBE and Protobuf order entry. This page helps you choose and operate a connection. For interface selection, see the [connectivity matrix](https://testnet.polyester.com/docs/developer-docs/getting-started/connectivity-matrix). For environment and contract details, see [environments and hosts](https://testnet.polyester.com/docs/developer-docs/getting-started/environments-and-hosts). ## Choose an API host The global API host is the default entry point. A regional hostname gives your client an explicit regional entry point. Choose one when you need to configure that entry point yourself and test connectivity from your own infrastructure. - **Global**\ `https://api.testnet.polyester.com` - **EU West · `bru`**\ `https://bru.api.testnet.polyester.com` - **US East · `iad`**\ `https://iad.api.testnet.polyester.com` - **US West · `pdx`**\ `https://pdx.api.testnet.polyester.com` - **Tokyo · `tyo`**\ `https://tyo.api.testnet.polyester.com` These API hosts serve the same REST, ConnectRPC, and realtime routes. Changing the API host does not change your account, API-key permissions, or request format. Configure the host separately from the operation path so switching hosts does not change the request body. For a public read, use [`GET /v1/spot/config`](https://testnet.polyester.com/docs/api-docs/rest/GET/v1/spot/config) or [`GetSpotConfig`](https://testnet.polyester.com/docs/api-docs/connect/marketdata.v1.MarketDataService/GetSpotConfig). Keep TLS certificate verification enabled and connect by hostname rather than a resolved IP address. ## Use the trade host for order entry Both binary trade WebSockets use `trade.api.testnet.polyester.com`: - **SBE order entry**\ `wss://trade.api.testnet.polyester.com/ws/trade.sbe` - **Protobuf order entry**\ `wss://trade.api.testnet.polyester.com/ws/trade.proto` The global and regional API hosts do not serve these trade paths. The trade host is not a replacement base URL for REST, ConnectRPC, or realtime subscriptions. There are no regional trade hostnames in the public connection contract. Authenticate the trade WebSocket upgrade with an Ed25519 API key. A user session JWT cannot authenticate this upgrade. Keep the socket open for successive commands instead of opening one per order. See [SBE connection and authentication](https://testnet.polyester.com/docs/developer-docs/sbe-websocket/connection-and-authentication) for signing, heartbeats, sequencing, and recovery. The Protobuf trade interface uses its own message encoding on the trade path above. ## Connect realtime streams Use the global API host or your chosen regional API host with `wss://`: - **Market data and account events**\ `wss://api.testnet.polyester.com/connection/websocket`\ Carries market subscriptions and authorized private streams such as balances, trades, transfers, and trigger events. - **Private order updates**\ `wss://api.testnet.polyester.com/v1/ws/private`\ Carries your orders, fills, and command outcomes. See [Private WebSocket](https://testnet.polyester.com/docs/developer-docs/connectrpc/private-websocket). Replace only the hostname to use a regional API endpoint. These are subscription connections; choose REST, ConnectRPC, or a trade WebSocket to submit order commands. Obtain connection and subscription tokens through `/v1/rt/token` and `/v1/rt/subscribe` on the API host. Use the authentication and refresh flow for the stream you selected. These tokens are distinct from a partner app's login JWT and from an API key's signing credentials. ## Reuse connections Keep a long-lived HTTP client and connection pool for REST and ConnectRPC. Enable connection reuse and consume or close response bodies so the client can return connections to its pool. Creating a new client for every request repeatedly pays connection and TLS setup costs. The public API endpoints accept HTTPS requests over HTTP/2 and HTTP/1.1. Allow HTTP/2 negotiation when your client supports it; multiplex requests on that connection. With HTTP/1.1, use persistent keep-alive connections and a pool suited to your concurrent workload. WebSocket routes use a GET upgrade handshake. Use a WebSocket client that supports the HTTP/1.1 `Upgrade: websocket` flow. An HTTP/2 connection for API requests does not replace a WebSocket connection, and ConnectRPC's Protobuf encoding does not itself require HTTP/2. Idle HTTP connections can close. Let the pool replace them and keep request deadlines separate from idle-connection settings. For WebSockets, follow the interface's heartbeat or ping/pong contract and keep reading while commands are in flight. ## Synchronize clocks and allow network access Synchronize your signing hosts with a reliable time source, such as NTP, and monitor drift. API-key signatures are time-bound, including signed trade WebSocket upgrades. Generate the timestamp and signature close to transmission, after any deliberate retry delay. For `TIMESTAMP_SKEW` or `AUTH_TIMESTAMP_SKEW`, correct the clock and sign again. Reusing the same signed upgrade after a disconnect can also fail replay protection. Follow [Ed25519 API keys](https://testnet.polyester.com/docs/developer-docs/authentication-security/ed25519-api-keys) for the exact signing and timestamp rules. If an API key has an IP allowlist, authorize the public egress addresses your clients actually use. Include failover egress paths before relying on them. Changing the destination API region does not add your client's source address to the allowlist. See [API key IP allowlists](https://testnet.polyester.com/docs/developer-docs/authentication-security/api-key-ip-allowlists). ## Reconnect with backoff Use exponential backoff with jitter and a maximum delay for transient connection failures. Honor `Retry-After` when present. Stagger reconnects across your clients so a disconnect does not trigger simultaneous retries. A regional fallback should be an explicit, tested client policy. After a realtime reconnect, obtain valid tokens, restore subscriptions, and resume from the last applied cursor where supported. If recovery is refused or a gap is detected, reload the required snapshot or history before treating local state as current. After a trade WebSocket disconnect, sign a new upgrade and follow that interface's sequence rules. Reconcile commands with uncertain outcomes before resending them. A lost connection does not prove that an order was rejected or cancelled. Fix authentication, permissions, allowlist denials, and malformed requests before retrying. For a `403`, inspect the response: an access challenge before the API or WebSocket opens is different from a Polyester permission error. See [troubleshooting](https://testnet.polyester.com/docs/developer-docs/getting-started/troubleshooting), [error responses](https://testnet.polyester.com/docs/developer-docs/error-handling/error-responses), and [error codes](https://testnet.polyester.com/docs/developer-docs/error-handling/error-codes).