🪙 MoMo Payment Gateway Demo (Go)

Overview

A clean-layer demo project showing how to integrate MoMo Sandbox (v2.0) with Go backend and minimal HTML UI.
Includes full flow: create payment → MoMo pay page → IPN → check-status → update order.

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Folder Structure

momo-demo/
├── api/               # HTTP routes and handlers (Gin)
├── service/           # Business logic
├── persistence/       # MoMo client, order repo
├── entity/            # Core domain entities
├── model/             # Request/response structs
├── static/            # Frontend pages (index.html, return.html)
└── main.go

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Flow Diagram

User ─▶ /create (backend)
       └─▶ MoMo payUrl ─▶ User pays
              └─▶ MoMo → /ipn (server→server)
                     └─▶ Verify signature & update order (PAID)
              └─▶ Redirect /momo/return
                     └─▶ FE queries /check-status → display result

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Run Locally

go run main.go

App starts on http://localhost:8083

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Test Flow

1. Open http://localhost:8083
2. Enter amount + description → click Pay with MoMo
3. Complete payment on MoMo sandbox page
4. Redirected back to /momo/return
   • It auto calls /check-status
   • Updates order via /update-order
5. Console logs will show signature verification, payment result, and order update.

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IPN Simulation (for localhost)

MoMo sandbox cannot reach localhost directly.
To test IPN:

curl -X POST http://localhost:8083/api/v1/payment/momo/ipn   -H "Content-Type: application/json"   -d '{ ... valid IPN payload with correct signature ... }'

Alternatively, expose your local server using ngrok or Cloudflare Tunnel. “

🖼 Result (Payment UI)

After calling POST /api/v1/payment/momo/create, the backend signs the request, calls MoMo's create API, and returns payUrl.

When you redirect the user to that payUrl, MoMo shows the checkout page with QR code for payment, like this:

• Left panel: order info (merchant, orderId, description, amount).
• Right panel: QR that the user scans in MoMo app.
• Countdown: how long the payment link is still valid.

From here:

1. The user scans and pays.
2. MoMo will call your IPN endpoint (/api/v1/payment/momo/ipn).
3. User gets redirected back to /momo/return?....

Notes

• The UI (return.html) automatically queries /check-status and updates order accordingly.
• The IPN endpoint (/api/v1/payment/momo/ipn) should only be called by MoMo, not from frontend.
• For real deployment, ensure your /ipn URL is publicly accessible (HTTPS).
• For sandbox testing, you can simulate IPN manually or use a tunnel.

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Contact for MoMo Sandbox Keys

💬 Need sandbox partnerCode, accessKey, or secretKey?
Request access via Hao Pham’s Facebook.

Notes

• Created by: Hao Pham
• Architecture: Clean modular structure
• API Sandbox: https://test-payment.momo.vn

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🟢 Goal: Demonstrate a full-stack MoMo integration flow in Go (signature, redirect, IPN verification, query status).