ecocash-instant-paymentlisted

# EcoCash Instant Payment (EIP) EIP lets a merchant's **server** charge a customer's EcoCash wallet. EcoCash sends the customer a **USSD PIN prompt**, the customer approves on their phone, and the merchant learns the outcome by callback or by looking the transaction up. Money moves, so correctness beats speed: most rules below exist because breaking them loses a payment, charges someone twice, or leaks the merchant PIN. This skill knows exactly what the EcoCash EIP guide at https://67even.github.io/ecocash-instant-payment-api/ knows (portal checked 21 Sep 2026). The `references/` files are generated from that guide; `references/portal-documentation-tab.md` and `references/portal-sdk-samples.md` are the portal's own pages, verbatim. ## 1. Setup and authentication 1. **Sandbox access comes from the EcoCash Developer Portal** (https://developers.ecocash.co.zw/portal): register → EcoCash Instant Payment → **Authentication** → *Request Sandbox Access* → username and password arrive in the portal **Inbox** (username starts `sbx_`) → *Save & Activate* → **Test Numbers** → add and OTP-verify an EcoCash-registered MSISDN. Walk a newcomer through `references/portal-onboarding.md`. 2. **Auth is HTTP Basic on every request**: `Authorization: Basic base64(username:password)`, plus `Content-Type: application/json`. No tokens, no expiry, no refresh. `401` (`E006`) = bad or malformed header; `403` (`E007`) = sandbox not activated (`references/authentication.md`). 3. **S