Testing notifications

Using example values, here’s a quick test to ensure your signature check works correctly:

item	Example value
`version`	1.0 (from the `User-Agent` header containing Volt/1.0)
`X-Volt-Timed`	1631525064
`X-Volt-Signed`	ed22494369277d25cf8c2293d142e5fddb9cecbea1f54e28ac16db0bee3b8009
`body`	{} (empty as in a test notification)
`notification secret`	9c0c8c97-c224-45ed-a195-23b54b1c67e5

Steps to test

Use the pipe delimiter (|) to concatenate the body, X-Volt-Timed and version in that order to create the string to hash

Concatenated string to hash

{}|1631525064|1.0

Hash this string using SHA256 and your notification secret

Example code (PHP)

$hash = hash_hmac('sha256', $string, $notification_secret);

If everything is correct, you should receive an HMAC signature that is identical to your X-Volt-Signed key

Generated HMAC signature for test notification

ed22494369277d25cf8c2293d142e5fddb9cecbea1f54e28ac16db0bee3b8009

Notifications containing real data

Note that when you receive real notifications the body element should be supplied as one continuous, unformatted, string – with no spaces or slashes to break up parameters – so your body might look like this:-

{"payment":"4a96elcb-8ae0-426c-a95e-d34f18fe32ad","reference":"EXAMPLE123","amount":8888,"status":"PENDING","detailedStatus":"BANK_REDIRECT"}

therefore your check string when concatenated (using the same X-Volt-Timed and version as earlier) would look like this:-

{"payment":"4a96elcb-8ae0-426c-a95e-d34f18fe32ad","reference":"EXAMPLE123","amount":8888,"status":"PENDING","detailedStatus":"BANK_REDIRECT"}|1631525064|1.0

and your HMAC signature (using the same notification secret as earlier) would be

Generated HMAC Signature for real data

d98e0106b07c3d0521cc5e2ff06b62f9a3db6c476d701fde0dde7bfb0eb78428

Check your working

Use our handy interactive form to test the HMAC signature calculation – post in the details you get from a Volt notification to re-calculate the signature using your notification secret.

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