API Development & Third-Party Integration in Kathmandu, Nepal

A distribution business in Kathmandu was running its inventory in one system, its accounting in another, and taking orders through a website that talked to neither. Every order meant someone manually re-typing the same information three times, and errors crept in every week, an order marked fulfilled in one system but not the other, stock counts that never quite matched. Nothing about their individual systems was broken. The problem was that none of them could talk to each other. Building the API connections between the three systems eliminated the manual re-entry entirely, and the data errors that used to happen weekly stopped happening at all.

API development and integration is the work of building and connecting the interfaces that let your website or software talk to other systems automatically, whether that is a third-party service like an SMS gateway or payment processor, or software you already run internally like accounting or inventory tools. When done well, it removes manual, repetitive, error-prone work and keeps your business data consistent across every system that touches it.

WebApp Nepal builds both sides of this: custom APIs that expose your own systems' data securely to other applications, and integrations that connect your website or web application to third-party services and existing business software you already rely on.

What We Build

Custom API Development

When your business needs to expose data or functionality to a mobile app, a partner's system, or a future product you have not built yet, we design and build REST APIs following proper conventions, secure authentication, and clear documentation so other developers, including your own future team, can work with it confidently.

Payment Gateway Integration

Beyond basic checkout, this includes handling the full lifecycle of a payment: timeouts, failed transactions, webhook retries, and reconciliation reporting for eSewa, Khalti, and major Nepali banks, built to handle real-world failure cases, not just the happy path that works in a demo.

SMS and Communication Gateway Integration

Order confirmations, appointment reminders, and OTP verification through SMS gateways used across Nepal, wired into your website or application so notifications go out automatically at the right moment without manual intervention.

Accounting and ERP Integration

Connecting your website's orders and transactions directly into accounting software eliminates duplicate data entry and the reconciliation errors that come with it. We integrate with whatever accounting or ERP system your business already uses wherever an API or reliable data-sync method exists.

CRM and Marketing Tool Integration

Automatically syncing new leads, form submissions, and customer data from your website into your CRM or email marketing platform, so your sales and marketing teams work from current data without manual exports and imports.

Shipping and Logistics Integration

For e-commerce businesses, connecting to courier and logistics partner APIs for real-time shipping rate calculation, automated label generation, and order tracking that updates customers without manual status updates from staff.

Our Integration Process

Step 1 - System and Data Audit

We map out exactly what systems you currently use, what data needs to move between them, and where manual re-entry or reconciliation is currently happening, since that friction is usually the clearest signal of where integration delivers the most value.

Step 2 - API Feasibility Check

We verify what each third-party system's API actually supports, since not every tool has a usable, well-documented API, and confirm the realistic scope of what can be automated before committing to a build.

Step 3 - Development and Testing

We build the integration with proper error handling for realistic failure scenarios, timeouts, partial failures, duplicate submissions, not just the scenario where everything works perfectly, since that is where most real-world integration bugs live.

Step 4 - Monitoring and Handover

We document the integration clearly and, where relevant, set up monitoring so failures are caught and flagged automatically rather than discovered days later when someone notices missing data.

API Development & Integration Pricing in Nepal

Simple third-party integrations, a single SMS gateway or a straightforward payment integration, typically range from NPR 20,000 to NPR 50,000. Custom API development and multi-system integrations involving accounting, ERP, or CRM platforms are scoped individually based on the systems involved and the complexity of the data being synced.

Why Choose WebApp Nepal for API Development & Integration

• Real failure-case handling: We build for timeouts, retries, and partial failures, not just the happy path that works in a demo.
• Works with what you already have: We integrate with your existing accounting, CRM, and business tools rather than requiring you to replace them.
• Nepal payment and SMS gateway experience: Production experience with eSewa, Khalti, and SMS providers used across Nepal, including their real-world edge cases.
• Clear documentation: Every integration is documented so your team, or any future developer, can maintain and extend it confidently.

Disconnected systems cost businesses real time and real errors every day through manual re-entry and reconciliation. WebApp Nepal builds the API connections that let your systems work together automatically, so your team spends less time moving data by hand and more time on work that actually needs a person.