Custom Software Engineering

API Design & Development

Overview

What is API Design & Development?

RESTful and GraphQL APIs designed contract-first in OpenAPI 3.0 — with JWT authentication, rate limiting, input validation, comprehensive error handling, and Swagger documentation auto-generated from code. Our team brings production-grade expertise to every engagement, ensuring your api design & development implementation delivers measurable business outcomes from day one. We architect, build, and maintain solutions that scale with your organisation and satisfy GCC regulatory requirements.

What's included

✓Contract-first OpenAPI 3.0 design with Swagger UI auto-generated documentation

✓JWT authentication with refresh token rotation and HTTP-only cookie security

✓Joi/Zod input validation and express-validator middleware layers

✓Rate limiting, CORS configuration, and OWASP Top 10 security hardening

✓Structured error responses and centralised error handling middleware

✓12-factor app principles for stateless, horizontally scalable services

Key Benefits

Why It Matters

The measurable outcomes our clients achieve with API Design & Development.

Security-First by Default

Every endpoint follows OWASP Top 10 guidelines — JWT auth, input validation, and injection prevention baked in.

Self-Documenting APIs

OpenAPI 3.0 specs and auto-generated Swagger UI keep your frontend and integration teams always unblocked.

Horizontally Scalable

Stateless services with externalised config and Docker containers run on ECS or Kubernetes without modification.

Sub-100ms Response Times

Non-blocking async architecture handles thousands of concurrent requests with sub-100ms p99 latency.

Delivery Lifecycle

How We Deliver

A structured, transparent process from kick-off to launch and beyond.

Discovery1 week

Requirements & API Contract Design

Define all endpoints, request/response schemas, and error codes in an OpenAPI spec — signed off by all consumers before development begins.

Planning3–5 days

Architecture & Versioning Strategy

Design API versioning strategy, authentication model, rate limiting policy, and error handling standards across all endpoints.

Architecture1 week

Project Scaffolding & Middleware Stack

Set up Express app with layered route → controller → service architecture, middleware stack, validation, and error handling.

Build4–8 weeks

Feature Development & Testing

Implement controllers and services in two-week sprints with automated tests and staging deployment each sprint.

QA & Security1 week

Security Hardening & Penetration Testing

OWASP audit, penetration testing for injection and auth bypass, secrets management review, and rate limiting validation.

Launch & ScaleOngoing

Load Testing & Production Deployment

k6 load tests to 10× expected peak traffic, bottleneck remediation, production deployment with Swagger docs and monitoring dashboards.

Use Cases

Industries & Scenarios

Where API Design & Development delivers the most impact.

◆SaaS backend APIs serving web and mobile clients

◆Mobile app backends with offline sync

◆Third-party integration middleware and adapters

◆Microservice API implementations

◆Real-time data APIs with WebSocket support

◆E-commerce order, inventory, and payment APIs

◆Authentication and authorisation service APIs

Tech Stack

Tools & Technologies

The proven technology stack we use to deliver API Design & Development.

Node.jsExpressOpenAPI 3.0Swagger UIJWTJoiJestk6DockerAWS ECS

FAQs

Frequently Asked Questions

Everything you need to know about API Design & Development.

Node.js excels for I/O-heavy APIs due to its non-blocking event loop. It also allows full-stack JavaScript teams to share code and tooling between frontend and backend. For CPU-intensive workloads (ML inference), we recommend Python microservices alongside Node.js.

We follow a strict layer pattern: routes handle HTTP routing and input validation; controllers orchestrate the response; services own all business logic and database access. No req/res objects enter the service layer. Files are kept under 300 lines with helpers extracted as needed.

We use URL-based versioning (/api/v1/, /api/v2/) for public APIs that may introduce breaking changes. For internal APIs consumed only by your own frontend, we prefer a single version with backward-compatible evolution.

Yes. Every project ships with an OpenAPI 3.0 specification, a Swagger UI at /api/docs in staging, and a Postman collection. For public APIs, we also produce a developer portal with authentication guides and code samples.

Sensitive endpoints use JWT bearer auth with short-lived access tokens (15 min) and HTTP-only cookie refresh tokens (7 days). Role-based access control middleware restricts access by user role. We also implement request signing for machine-to-machine API calls.