# Limitations & non-features

What API-key SDKs intentionally omit, and where to go instead.

Python, Go, and Rust are **API-key SDKs**. They share the ConnectRPC + WebSocket Protobuf trading surface. They do **not** replace the TypeScript browser client.

## Not available here

| Capability                          | Use instead                                                                                                                                                                        |
| ----------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Wallet / browser login              | [TypeScript SDK](https://testnet.polyester.com/docs/sdk/typescript/get-started/overview)                                                                                           |
| Session MFA enrollment / challenges | TypeScript SDK                                                                                                                                                                     |
| Account resolve / lookup            | TypeScript / session clients                                                                                                                                                       |
| SBE WebSocket                       | [SBE getting started](https://testnet.polyester.com/docs/developer-docs/sbe-websocket/getting-started)                                                                             |
| FIX Classic / FIX-SBE               | [FIX Classic](https://testnet.polyester.com/docs/developer-docs/fix-classic/getting-started), [FIX-SBE](https://testnet.polyester.com/docs/developer-docs/fix-sbe/getting-started) |

Subaccount MFA **requirement flags** (policy) may still appear on API-key policy APIs, that is not the same as performing MFA challenges in this SDK.

## Easy to miss

- On-chain **Funding → Trading** and **Funding → external** via the `chain` module (not ConnectRPC). See [Deposits & withdrawals](https://testnet.polyester.com/docs/sdk/go/guides/deposits-and-withdrawals).
- Collaboration wrappers (polychart / layout / whiteboard / social verification) may appear in the client tree, but live API-key access is limited: whiteboard and social verification are JWT/session-only, and some layout/polychart endpoints may be unmounted. Treat them as non-features for automated trading bots. Thin [reference](https://testnet.polyester.com/docs/sdk/go/reference/polychart) pages exist for discovery only.
- Client aliases and sync/async differences, see [Architecture](https://testnet.polyester.com/docs/sdk/go/concepts/architecture).

> **Capability matrix**
>
> Compare languages: [SDK capability matrix](https://testnet.polyester.com/docs/developer-docs/getting-started/sdk-capability-matrix). Transports: [connectivity matrix](https://testnet.polyester.com/docs/developer-docs/getting-started/connectivity-matrix).