Our API development team designs REST and GraphQL APIs plus integrations with Stripe, CRMs, ERPs, and legacy systems.
API services
- Custom REST and GraphQL APIs
- Payment gateway integrations
- CRM and ERP connections
- Webhooks and event-driven sync
- API documentation and versioning
Technologies we use
How we deliver
Discovery & scoping
Free 30-min call, requirements workshop, technical feasibility, and fixed-price proposal.
Architecture & design
System design, wireframes, and sprint roadmap with clear milestones and acceptance criteria.
Agile development
2-week sprints, weekly demos, code reviews, and continuous integration from day one.
QA & security
Automated tests, UAT, performance checks, and security review before every release.
Launch & support
Zero-downtime deployment, monitoring, documentation, and SLA-backed post-launch support.
Transparent pricing
Fixed-price packages — no hourly surprises. Final quote after free discovery call.
Single integration
- One third-party API
- Webhooks
- Error handling
- Documentation
API platform
- REST or GraphQL
- Auth & rate limits
- Versioning
- Postman/OpenAPI
Enterprise bus
- Multi-system sync
- Event-driven
- Monitoring
- SLA support
Featured case study
Unified API for CRM + billing + warehouse
Challenge: Three disconnected systems caused sync errors and manual reconciliation daily.
Result: Real-time sync · 90% fewer errors · documented OpenAPI spec
Why CSNexa
Fixed-price clarity
Scope, timeline, and cost agreed before a single sprint — no surprise invoices.
Senior-only engineers
No junior bait-and-switch. Your project is led by architects with 10–15+ years in production software.
Global delivery
UK, US, UAE, Australia — timezone overlap, fluent English, Slack + Jira transparency.
NDA & full IP
You own 100% of source code, designs, and documentation on completion.
Frequently asked questions
REST or GraphQL?
REST for most B2B and mobile backends; GraphQL when clients need flexible queries — we advise during discovery.
How do you document APIs?
OpenAPI/Swagger specs, Postman collections, and developer guides are included in every API engagement.
Can you integrate Stripe, Salesforce, etc.?
Yes — payments, CRMs, ERPs, shipping, and custom legacy systems via REST, SOAP, or webhooks.
Clear scope and milestones before development starts.
15+ years building production software.
You own the code on completion.
Discuss your API project
Book a free 30-minute scoping call. We respond within 4 hours on business days.