# Environments

Default testnet endpoints and how to point the client at another deployment.

API-key SDKs default to Polyester **testnet / devnet**:

| Setting       | Default                           |
| ------------- | --------------------------------- |
| API URL       | `https://api-devnet.polyester.ai` |
| WebSocket URL | `wss://api-devnet.polyester.ai`   |

Pass `api_url` / `ws_url` (Python), `APIURL` / `WSURL` (Go), or `api_url` / `ws_url` (Rust) on the client config to override. Scripts using `from_env` still need constructor `api_url` / `ws_url` for URL overrides, those env vars are not loaded.

On-chain Funding helpers use `POLYESTER_TESTNET_ENVIRONMENT` (Python/Go/Rust `chain` modules) for contract addresses, RPC, and account-abstraction endpoints on testnet. See [Chain helpers](https://testnet.polyester.com/docs/sdk/python/reference/chain) and [Funds & Transfers](https://testnet.polyester.com/docs/developer-docs/funds-transfers/overview).

Do not hard-code production URLs until your account team confirms the production API host.