APIs & Data Synchronization

Custom API Integration & Web Application Development

Connect your website to payment gateways, CRMs, ERPs, and cloud microservices. We build secure REST API integrations, automated webhook handlers, and seamless two-way data synchronizations.

RESTful API Endpoints & Client Integration Payment Gateways (Stripe, PayPal, Merchant APIs) Automated Webhook Listeners & Data Handlers CRM Synchronization (HubSpot, Salesforce, Klaviyo) Secure Secrets Management & Rate Limiting
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Connecting Your Digital Ecosystem Without Data Silos

Modern businesses run on multiple software platforms: payment processors, customer relationship management (CRM) databases, email automation tools, accounting software, and inventory warehouses. When these systems don't communicate with each other, your team is forced into manual copy-pasting, data discrepancies emerge, and customer orders get delayed.

I build custom API integrations and automated webhook listeners that bridge your website with third-party digital ecosystems. From integrating Stripe custom checkout sessions and automated PayPal notifications to syncing lead capture forms with HubSpot or Airtable, every connection is engineered for security, reliability, and graceful error handling.

Whether you need to connect an existing WordPress or Shopify platform to a proprietary backend, or build serverless API endpoints for a custom web application, I deliver clean, documented code that runs reliably 24/7.

Custom API Integration Deliverables

Robust backend connections and automated data pipelines engineered for enterprise reliability.

Payment Gateway Integrations

Seamless integration of Stripe, PayPal, and regional payment gateways: custom checkout forms, tokenized cards, webhook verifications, and automated refunds.

CRM & Marketing Automation Sync

Connect web lead forms to HubSpot, Salesforce, ActiveCampaign, or Mailchimp with custom property mapping, deal creation, and automated tag assignment.

Automated Webhook Processing

Build secure webhook listener endpoints that process incoming events (order created, invoice paid, subscription cancelled) and update your database in real-time.

Two-Way Database & Inventory Sync

Synchronize inventory counts, customer records, and order statuses between your website and third-party ERP or warehouse management systems.

OAuth2 & Authentication Integrations

Implement secure Single Sign-On (SSO) with Google, Apple, or custom OAuth2 identity providers with encrypted session management.

Serverless Functions & Microservices

Deploy lightweight Vercel or AWS Lambda serverless functions that act as secure middleware proxies, keeping confidential API secrets off client browsers.

Enterprise Security, Token Handling & Rate Limiting

Security is the number one priority in API development. Client credentials and private API keys are never exposed in client-side code. All external requests are routed through authenticated serverless functions or backend workers protected by signature verification (HMAC) and rate-limiting safeguards.

Every integration includes automated retry logic with exponential backoff and error logging, ensuring that temporary third-party API downtimes never cause lost transactions or unhandled crashes.

Is This Service Right for Your Business?

Ideal For You If

  • Businesses needing to connect custom website forms directly into their internal CRM or ERP software.
  • E-commerce merchants requiring custom payment gateway or localized checkout integrations.
  • Startups building web apps that rely on external data APIs (weather, financial, sports, or AI).
  • Companies wanting to automate manual data entry across multiple cloud platforms.

Consider Alternatives If

  • Legacy on-premise systems with no internet access, no REST/SOAP endpoints, and no documentation.
  • Simple websites that only need a standard email contact form without external database syncing.

Development & Delivery Process

A structured 4-step workflow that keeps your project on schedule, within scope, and aligned with your conversion goals.

01

API Documentation & Endpoint Analysis

We review the technical specifications, authentication models (OAuth, Bearer token, API key), and payload formats of all systems to be connected.

02

Data Schema Mapping & Sandbox Testing

I map JSON field structures, set up sandbox developer accounts, and test sample requests/responses using Postman to verify payloads.

03

Middleware Coding & Webhook Verification

I write the serverless integration functions, implement signature verification, error logging, and connect live event triggers.

04

Production Cutover & Monitoring

We execute end-to-end live transactions, verify successful data synchronization, and configure error notification alerts.

Why Work With Adil Khan?

When you hire ADILwp, you work directly with a senior developer and SaaS builder with over 7 years of hands-on experience building for international businesses across the United States, United Kingdom, Canada, and Europe. There are no communication middlemen, no outsourced junior code, and no hidden surprises.

With an authentic 4.7★ track record across 44+ verified marketplace reviews, my priority is delivering maintainable code, sub-second loading performance, and clean designs that measurably convert visitors into paying clients.

Frequently Asked Questions

How do you keep my private API keys and customer data secure?

Private API keys are stored in encrypted environment variables on secure servers or edge runtime environments (like Vercel). They are never written into frontend JavaScript or exposed in public Git repositories. Furthermore, all data transmissions use encrypted HTTPS and TLS 1.3.

What happens if a third-party API is temporarily offline?

We implement robust error handling with retry logic and fallback mechanisms. If an external service experiences temporary downtime, the incoming event is queued or logged, and your customer receives a clear, friendly notification rather than an ugly server crash.

Can you connect my website to an older SOAP or XML API?

Yes. While modern REST and GraphQL APIs using JSON are standard, I have extensive experience building middleware transformers that parse XML/SOAP responses and convert them into clean modern JSON for your website.

Can you integrate custom payment gateways like Stripe or PayPal?

Yes. I regularly build custom Stripe Elements checkout forms, recurring subscription billing pipelines, and PayPal Express integrations with automated webhook listening to confirm payments before fulfilling orders.

Do you provide API documentation for our internal developers?

Yes. Every custom API route or serverless function comes fully documented with sample request/response payloads, authentication instructions, and environment variable requirements.

Have a Project in Mind?

Let's Build Something High-Performing Together.

Available for freelance contracts, full builds, and ongoing partnerships worldwide. Reach out directly through your preferred channel.

Instant Chat WhatsApp (+92 305 5931818)
Official Inquiries contact@adilwp.com
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Prefer direct email? contact@adilwp.com or for quick replies: adilwordpress7@gmail.com