Daraja Agent KitCallback receiver
By the end of this track you can write a small service that charges, stores every event and notifies your app.
0/6 finished
Step 1
The idea
POST /callbacks/<secret-token> stores the raw body, replies {"ResultCode": 0, "ResultDesc": "Accepted"}, then processes in the background: find the row, ignore it if it is already final, check the amount, and move it to confirmed or failed.
Step 2
How it works
The order of work
- Save the raw body.
- Reply with
{"ResultCode": 0, "ResultDesc": "Accepted"}. - In the background: find the row by
CheckoutRequestID. - If it is already final, stop.
- Check the amount, then move it to confirmed or failed through your one state function (D1).
The secret path
Put a long random token in the callback path, such as /callbacks/3f9c…, and reject other paths. It stops casual fake callbacks; checking the amount and the ID stops the rest.
Test it
Pay one prompt, cancel another, then POST a saved success body a second time. Nothing should change.
Step 3
Common mistakes
- Processing before replying.
- Skipping the amount check.
Go deeper
What happens if the same callback arrives twice?
Answer in your own words first.
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Nothing changes. The row is already final, so the second one is ignored.