Airtel Money

Collections through Airtel Africa's Open API, the one gateway for every
Airtel Money country. A collection is a USSD push the caller approves on
their handset, so it is asked for and then checked; the airtel_collect
template shows the whole conversation.

UAT

1. Sign up at https://developers.airtel.africa, create an app and enable
   Collection on it. The app's client id and secret are the two secrets.
2. UAT answers at https://openapiuat.airtel.africa; the token lasts three
   minutes, so each step fetches its own.
3. Airtel's test numbers decide the outcome in UAT; the portal lists them.

Live

Airtel issues production keys per country once the merchant is onboarded.
The host is https://openapi.airtel.africa; the country and currency go in
every request as X-Country and X-Currency, and the caller's number is
sent without its dialling code, which is why the account carries one.

Outcomes

• Collect a payment answers 200 with status.success true once the
  prompt is on the handset, and status.success false with a message when
  Airtel refuses.
• Check a payment reads TS (paid), TIP (in progress) or TF
  (failed) from data.transaction.status, under body since status at
  the top of a stored answer is the HTTP status.