APIs That Connect, Scale, and
Never Break in Production
A poorly designed API becomes a maintenance burden — versioning conflicts, undocumented edge cases, security gaps, and integration failures that cascade across your entire system. At Aavyalabs, we build APIs contract-first using OpenAPI specification, with security, rate limiting, and error handling designed before the first endpoint is written.
Built in C#.NET and Golang — production-grade, load-tested, and documented so your developers and partners can actually use them.
Our API Development Services
From custom REST API development to microservices, integrations, and full API lifecycle management.
Custom REST API Development
High-performance RESTful APIs built in C#.NET and Golang — with proper versioning, pagination, error handling, rate limiting, and OpenAPI/Swagger documentation from day one.
Microservices Architecture
Decompose monolithic systems into independently deployable, loosely-coupled microservices — with service discovery, API gateway, and event-driven communication patterns.
Third-Party API Integration
Robust integrations with payment gateways, CRMs, ERPs, messaging platforms, and custom partner APIs — with retry logic, webhook management, and idempotency guarantees.
API Security & Compliance
OAuth 2.0, JWT authentication, RBAC, rate limiting, input validation, PII redaction, and audit logging — built to meet OWASP API Security standards and compliance requirements.
API Documentation & Developer Experience
Interactive OpenAPI/Swagger documentation, code samples, SDKs, and developer portals — making your API easy to understand, test, and adopt by internal and external developers.
API Lifecycle Management
Version management, deprecation strategies, breaking-change governance, performance monitoring, and usage analytics — ensuring your APIs remain reliable and evolve safely over time.
Service Quick Facts
Key delivery metrics and technical specifications at a glance.
| Metric / Attribute | Specification Details |
|---|---|
| Average Delivery Time | 4–8 weeks for custom REST/GraphQL APIs and integrations |
| Typical Team Setup | 1 API/Integration Architect, 1 Backend Engineer, 1 QA Specialist |
| Primary Technologies | C#.NET Core, Golang, PostgreSQL, OpenAPI/Swagger, OAuth 2.0, JWT |
| Service Model | Fixed-price milestone SOW or Dedicated sprint velocity billing |
| Post-Launch Support | API Gateway SLA Monitoring, Schema Validation testing, and Security Auditing |
Our API Delivery Process
A contract-first methodology that produces reliable, well-documented APIs — ready for production from day one.
API Design & Contract
We design your API contract first — using OpenAPI specification — agreeing on endpoints, data models, error codes, and authentication before any implementation begins.
Security Architecture
We define the authentication strategy, authorisation model, and data protection requirements upfront — so security is baked in, not bolted on.
Development & Unit Testing
API endpoints developed in C#.NET or Golang with comprehensive unit and integration tests — achieving >80% coverage on business logic before any QA review.
Integration Testing
End-to-end integration tests across all connected systems — verifying data flow, error handling, and edge cases under realistic conditions.
Performance Testing
Load and stress testing against defined throughput targets — identifying bottlenecks, optimising queries, and validating that SLAs are met under peak load.
Deployment & Monitoring
CI/CD deployment to cloud or on-premise, with API gateway configuration, health checks, alerting, and usage dashboards — so you can monitor adoption and performance in real time.
Why Aavyalabs for API Development?
Contract-First Engineering
We design the API specification before writing code — aligning teams, defining contracts, and catching design flaws before they become expensive implementation problems.
Performance-Engineered
We benchmark APIs against real-world throughput requirements — profiling, query optimising, and caching strategically so your API holds up under production load.
Security by Default
OAuth 2.0, JWT, RBAC, rate limiting, and OWASP API Top 10 compliance are standards on every API we build — not optional extras.
Integration Depth
We've integrated with dozens of third-party systems — Razorpay, Stripe, Salesforce, SAP, Twilio, AWS services, and custom partner APIs — with robust error handling and retry strategies.
Frequently Asked Questions
Common questions about REST API development, microservices, and integration engineering.
What is REST API development?
A REST API is a structured HTTP interface that allows software systems to communicate. REST APIs are the standard way modern applications expose their data and functionality to web frontends, mobile apps, third-party partners, and internal services — enabling integration, automation, and ecosystem extensibility.
What is the difference between REST and GraphQL?
REST uses fixed endpoints where the server defines what data is returned. GraphQL uses a single endpoint where the client specifies exactly what fields it needs. REST is simpler and cacheable; GraphQL is better for complex, flexible data requirements with many entity relationships. We build both depending on your use case.
What languages do you use to build APIs?
We primarily build APIs in C#.NET (ASP.NET Core) for enterprise .NET ecosystems, and Golang for high-performance, concurrency-heavy services. Both produce production-grade APIs with strong typing, comprehensive error handling, and OpenAPI documentation.
How do you secure APIs?
API security involves multiple layers: authentication (OAuth 2.0, JWT, API keys), authorisation (RBAC, scopes), transport security (TLS 1.3), input validation, rate limiting, CORS configuration, and output sanitisation. For regulated industries, we also implement audit logging and PII redaction.
Can you integrate our application with third-party APIs?
Yes. We build integrations with payment gateways (Razorpay, Stripe), CRMs (Salesforce, HubSpot), ERPs (SAP, Dynamics), messaging platforms (Twilio, SendGrid), cloud services, and custom partner APIs — with error handling, retry logic, and webhook management.
Ready to Build APIs That Power Your Business?
Whether you need a new API built from scratch, an existing one secured and optimised, or a complex integration engineered — let's talk. We'll give you a clear scope and timeline in our first conversation.
Discuss Your API Project