Nagad

The Nagad plugin takes payments through the Nagad merchant payment gateway. The client presses a button on the invoice, pays on Nagad's page and returns to the invoice. It works in Bangladeshi taka (BDT) only. It is free and suits shops in Bangladesh that have a Nagad merchant account. With only a personal Nagad number use Mobile Wallet. What all gateways share is in Payment gateways.

Nagad works differently from a gateway with a simple password: your requests are signed with your private key and the sensitive data is encrypted with Nagad's public key. That is why the setup asks for two long keys.

Switching it on

1. Open Setup → Payment Gateways, tab All Payment Gateways, press Activate on Nagad.
2. Enter the merchant ID and paste the two keys. Save.
3. Test in the sandbox, then switch Test mode off.

Activation creates a small table where the plugin remembers each payment it starts; uninstalling drops it. The PHP openssl extension is needed (the installer requires it anyway) and so is curl.

Settings

On the page the settings are grouped as Nagad (the merchant ID) and Keys. Without all three the invoice shows Nagad is not set up yet: the merchant ID or a key is missing.

What Nagad needs from you

• A Nagad merchant account and, from Nagad, the merchant ID and Nagad's public key (the "PGW public key"). Your merchant private key is the other half of the key pair you registered with Nagad. Follow the onboarding steps Nagad gives you for how the pair is made and registered.
• Nagad may ask you to register your site address, your callback address and your server's IP address. Ask them when you get the credentials. The callback address is shown at the bottom of the settings page: https://billing.example.com/callback/nagad.
• Sandbox and live use different credentials. Keep both sets safe; switch with Test mode.

How a payment goes

1. The client presses Pay ... with Nagad on an unpaid invoice in BDT.
2. Step one, initialize: AIOBilling sends Nagad an encrypted and signed request for a new order (the order ID looks like I12T123456789) and gets a payment reference and a challenge back. The answer's signature is checked.
3. Step two, complete: the plugin sends the amount and the challenge, with your callback address, and Nagad answers with the address of its payment page. The client is sent there.
4. The client pays. Nagad sends the browser back to the callback address with the order ID and the payment reference.
5. The plugin never trusts what comes in the address. It asks Nagad to verify the payment reference. The status must be Success, and the order ID, the amount and the merchant ID must match what was asked for.
6. The transaction ID is Nagad's issuer reference (or the payment reference), the invoice is marked paid and the client returns to the invoice. A payment that is reported twice is recorded once.

As with bKash there is no separate server notice: the payment is recorded when the browser returns. If a client paid but the invoice is unpaid, check the Nagad merchant portal and use Add Payment on the invoice.

Refunds

There is no refund call. Refund in Nagad and record it on the invoice's Refund tab with Offline refund (record only).

Testing in the sandbox

1. Get the sandbox merchant ID and keys from Nagad, enter them and switch Test mode on.
2. Pay a small BDT invoice from the client area with Nagad's test account.
3. The invoice should turn Paid. Then switch to the live credentials and Test mode off.

Troubleshooting

Look in Billing → Gateway Log (filter Nagad) and Utilities → Module Log.

More in Troubleshooting.