WHMCS

Who this is for

• You run a WHMCS billing panel (8.0 or newer) for hosting, domains, or any recurring service
• You want to accept eSewa, Khalti, and configured Fonepay from Nepali customers in one module - no separate integrations to reconcile
• You already have (or can create) a PayBridgeNP account with a sk_live_… or sk_test_… API key
• Your invoice currency is NPR

What you get

• eSewa + Khalti + Fonepay in one module. Let the payer choose from available methods, or force one provider. No duplicate webhook endpoints.
• Hosted checkout. Customers pay on a mobile-friendly PayBridgeNP page. Nothing is embedded in WHMCS.
• Refunds from WHMCS admin, full or partial. A confirmed Khalti refund is reported to WHMCS. An eSewa refund is recorded as requires_action, and WHMCS shows it declined with instructions: pay it out in the eSewa merchant portal, then mark the invoice refunded. Refund Fonepay payments from the PayBridgeNP dashboard.
• Signed webhooks. Every payment.succeeded / payment.failed event is checked (HMAC-SHA256, 5-minute replay window); forged events get a 400.
• No double posting. WHMCS’s checkCbTransID stops a replayed webhook posting twice to tblaccounts.
• Gateway Log. Checkouts, payments, refunds and errors are always logged in Utilities → Logs → Gateway Log. Debug Logging adds full API bodies, browser returns and raw webhooks. Keys and signatures are scrubbed, so logs are safe to share with support.
• Public Callback URL. Optional, for when your WHMCS System URL is not publicly reachable, including local development through a tunnel (cloudflared / ngrok).
• GPL-2.0-or-later licensed. Same license family as WHMCS itself.

How it plugs in

┌────────────────┐  1. pays invoice (picks PayBridgeNP)    ┌───────────────┐
│   Customer     │ ───────────────────────────────────────▶│     WHMCS     │
└────────────────┘                                         └──────┬────────┘
                                                                  │ 2. paybridgenp_link()
                                                                  │    creates checkout session
                                                                  ▼
                                                         ┌──────────────────┐
                                                         │  PayBridgeNP     │
                                                         │  hosted checkout │
                                                         └────────┬─────────┘
                                                                  │ 3. customer pays (eSewa / Khalti / Fonepay)
                                                                  ▼
┌────────────────┐   5. return URL → invoice view         ┌──────────────────┐
│   Customer     │ ◀───────────────────────────────────── │  callback.php    │
└────────────────┘      (no state mutation here)          └──────┬───────────┘
                                                                  │
                                                                  │ 4. signed webhook (authoritative)
                                                                  ▼
                                                         ┌──────────────────┐
                                                         │  callback.php    │
                                                         │  → invoice Paid  │
                                                         └──────────────────┘

WHMCS Marketplace

What’s next

• Install the WHMCS module - download, extract, activate, configure (about 10 minutes)
• How it works - payment flow, invoice state transitions, webhook handling, security model
• Troubleshooting - common issues and how to fix them