# Broker API FAQs

> Common questions about MyStocks partner onboarding, accounts, funding, events, reconciliation, and production access.

## Do I need a separate key for sandbox?

Yes. Sandbox keys use `sk_sandbox_`; production keys use `pk_live_`. Keep credentials server-side and never ship a full production key in a browser bundle.

## Are writes safe to retry?

Only when you reuse the same `Idempotency-Key`. All partner mutations require the header. A different payload with the same key returns an idempotency mismatch.

## How should I receive state changes?

Use signed webhooks for server-to-server processing and `/stream` SSE for live application updates. Both are at-least-once; deduplicate by `eventId`.

## Does sandbox represent production settlement timing?

No. Sandbox uses virtual funds and accelerated execution. Production settlement and custody timing follow the relevant market, executing broker, custodian, and contractual SLA.

## What is required before production access?

Complete the required certification checks, attach HTTPS evidence, and request a MyStocks operations review through [Going Live](/partners/docs/going-live).