What is API & systems integration?
API integration connects separate software so data moves automatically. NNT Software builds reliable integrations between business systems and platforms such as Stripe, PayPal, Salesforce, HubSpot, QuickBooks, Xero, Shopify, Amazon, WhatsApp Business, Twilio and shipping carriers, plus custom REST and GraphQL APIs for partners.
Re-typing the same order into your store, ERP, shipping portal and accounting tool wastes hours and creates errors. Integrations make your stack act like one system.
We build integrations that are logged, retry-safe and monitored — because third-party APIs change.
Key benefits of API & systems integration
No double data entry
Orders, customers and invoices flow automatically between systems.
Real-time visibility
Customers and teams see live status everywhere.
Fewer errors
Automated transfers remove typing mistakes.
Faster partner onboarding
Documented APIs let partners connect quickly.
Future-proof stack
Swap tools without rebuilding everything.
Our API & systems integration capabilities
Payments
Stripe, PayPal, Adyen, Checkout.com and regional gateways, with reconciliation.
CRM & marketing
Salesforce, HubSpot and Zoho sync for leads, deals and customers.
Accounting & ERP
QuickBooks, Xero, NetSuite, Tally and SAP connectors.
Messaging
WhatsApp Business, Twilio SMS and email automation.
Commerce & logistics
Shopify, WooCommerce, Amazon, and carrier APIs like FedEx, DHL and Aramex.
Custom APIs
Documented REST/GraphQL APIs with OAuth and rate limits.
Outcomes clients typically see: no double data entry, real-time customer updates and fewer billing mistakes.
Common use cases
Commerce integrations
Store, ERP, shipping and accounting connected.
CRM sync
Leads and deals synced with marketing and support tools.
Partner APIs
Secure APIs exposing your services to partners.
Legacy bridges
Middleware giving old systems modern APIs.
Technology stack
We choose technology for long-term maintainability, performance and the skills available to your team. Typical API & systems integration stack:
- REST
- GraphQL
- Webhooks
- Node.js — fast, event-driven JavaScript runtime for APIs and real-time features
- Python — the leading language for data, AI and automation workloads
- OpenAPI
How much does API & systems integration cost?
The final cost of API & systems integration depends on five main factors: the number of user roles and screens, the integrations required (payments, identity, ERP, CRM, messaging), compliance and security requirements, the seniority mix of the team, and the engagement model.
We always start with a short discovery phase so the estimate you receive is fixed and written, not a vague range. Ongoing maintenance and hosting typically add 15–20% of the build cost per year.
| Scope | Typical timeline |
|---|---|
| Single integration | 1–3 weeks |
| Integration hub (5+ systems) | 2–4 months |
| Public partner API | 6–12 weeks |
| Monitoring & support | Ongoing |
How we deliver API & systems integration projects
Every API & systems integration engagement follows the same disciplined, transparent process. You always know what is being built, what it costs and what comes next.
1. Discovery and scoping (1–2 weeks)
Workshops with your stakeholders to understand goals, users, workflows and constraints. We document requirements as user stories, map integrations and agree success metrics, then share a written scope, milestone plan and fixed estimate for API & systems integration.
2. UX and architecture (1–3 weeks)
Designers produce user flows and a clickable prototype while architects choose the stack, hosting, data model and security controls. Nothing is built until you sign off the prototype and architecture.
3. Agile development (two-week sprints)
Developers build in short sprints with a demo at the end of each one. You see working software early, give feedback continuously and can reprioritise the backlog at any time.
4. Quality assurance
Dedicated QA engineers write test cases, run manual and automated regression tests, check performance and review security basics before every release. Defects are tracked openly.
5. Launch
We deploy with zero-downtime pipelines, migrate data if needed, monitor closely during the first days and train your team or users.
6. Support and growth
After launch, SLA-backed support covers bug fixes, monitoring, security patches and continuous improvement, so the product keeps improving as your business grows.
Engagement models and pricing options
You can engage NNT Software for API & systems integration in whichever way fits your budget, risk appetite and internal team.
| Model | Best for | How billing works |
|---|---|---|
| Fixed price | Clearly defined scope and deadline | Agreed price split into milestone payments |
| Dedicated team | Long-term products and evolving roadmaps | Monthly fee per engineer, scale up or down |
| Time & materials | Exploratory or fast-changing work | Hourly or daily rates against actual effort |
| Hybrid | Fixed MVP followed by ongoing growth | Fixed first phase, then monthly team |
Whichever model you choose, you own the source code and intellectual property, work directly with the engineers, and receive weekly progress reports and demos.
Security, quality and compliance standards
Security and quality are built into every API & systems integration project from the first sprint, not added before launch.
- Secure coding aligned with the OWASP Top 10 and peer code reviews on every change
- Encryption in transit (TLS) and at rest, secrets stored in managed vaults
- Role-based access control, multi-factor authentication and audit logs
- Automated tests in CI pipelines, plus manual exploratory and regression testing
- Data-protection by design for GDPR, CCPA, PDPL, DPDP and similar laws
- Infrastructure as code, monitoring, alerting and tested backups
- NDA before discovery and full IP assignment in the contract
Common API & systems integration mistakes to avoid
- No retry or idempotency, causing duplicates.
- No logging, so failures go unnoticed.
- Hard-coding credentials.
- Ignoring API rate limits.
- Not versioning your own APIs.
API & Systems Integration trends for 2026
- Event-driven integrations with webhooks and queues.
- Embedded iPaaS inside SaaS products.
- Open finance and open data APIs.
- AI agents consuming APIs directly.
How to choose a API & systems integration partner
Use this checklist when comparing vendors:
- Has built integrations with your tools
- Designs retries and alerts
- Documents with OpenAPI
- Secures secrets properly
- Monitors after launch
- Handles API version changes
Why companies outsource to NNT Software in India
India is the world's largest software-services hub, and NNT Software combines that talent depth with a product mindset. For API & systems integration, clients typically save 40–60% compared with agencies in the United States, United Kingdom, the Gulf or Australia, without compromising on quality or communication.
Our engineers work in English, overlap daily with your business hours and follow documented processes. You get a named project manager, direct access to developers, and the stability of a company that has delivered more than 2,000 projects since 2010 and runs eight of its own SaaS products.
API & Systems Integration for clients worldwide
We deliver API & Systems Integration for businesses in 95 countries across North America, South America, Europe, Gulf & Middle East, Asia Pacific and Africa. Overlapping working hours, local payment and compliance knowledge, and remote-first collaboration make distance irrelevant.
- North America: United States, Canada, Mexico, Panama, Costa Rica, Dominican Republic, Guatemala, Puerto Rico, Jamaica, Trinidad and Tobago, The Bahamas
- South America: Brazil, Argentina, Colombia, Chile, Peru, Uruguay, Ecuador, Paraguay
- Europe: United Kingdom, Ireland, Germany, France, Netherlands, Belgium, Luxembourg, Spain, Portugal, Italy, Switzerland, Austria, Sweden, Norway, Denmark, Finland, Poland, Czech Republic, Romania, Greece, Malta, Cyprus, Estonia, Lithuania, Hungary, Croatia, Bulgaria, Serbia, Slovakia, Slovenia, Latvia, Iceland, Georgia, Armenia
- Gulf & Middle East: United Arab Emirates, Saudi Arabia, Qatar, Kuwait, Bahrain, Oman, Türkiye, Jordan
- Asia Pacific: Australia, New Zealand, India, Singapore, Malaysia, Indonesia, Thailand, Vietnam, Philippines, South Korea, Sri Lanka, Bangladesh, Kazakhstan, Uzbekistan, Azerbaijan, Nepal, Cambodia, Fiji
- Africa: South Africa, Nigeria, Kenya, Egypt, Morocco, Ghana, Rwanda, Mauritius, Tanzania, Uganda, Ethiopia, Côte d'Ivoire, Senegal, Tunisia, Botswana, Zambia
Select a country from the market list on this page for regulation, payments and delivery details specific to that market.
Next steps
Ready to discuss API & systems integration? Here is how to get started with NNT Software:
- Share your goals, users, must-have features and timeline through the contact form, email or WhatsApp.
- Join a free 30-minute discovery call with a solution architect — we sign an NDA first if you prefer.
- Receive a written proposal within 48 hours: scope, milestones, team, timeline and fixed estimate.
- Kick off with a discovery workshop and see working software in your first sprint demo.