API Development — Connect Your Systems, Unlock Business Value
Optimum Web designs and builds production-grade APIs from Chisinau, Moldova — REST, GraphQL, and gRPC interfaces that connect your web apps, mobile apps, partner integrations, and microservices. Since 1999.
- REST APIs — Resource-oriented design, OpenAPI/Swagger documentation
- GraphQL — Schema-first design, DataLoader optimization, subscriptions
- Integration — Stripe, PayPal, Auth0, Twilio, Salesforce, HubSpot
- API security — OAuth2, JWT, rate limiting, input validation
- Testing — Unit, integration, contract (Pact), performance (k6)
- Gateway & management — Kong, AWS API Gateway, versioning, analytics
Industries: FinTech · E-commerce · SaaS · Healthcare · Logistics
Our Capabilities
REST API Development
We design and build REST APIs that are the backbone of modern software systems — connecting your frontend applications, mobile apps, third-party integrations, and internal services. Our REST APIs follow industry best practices: resource-oriented design with consistent URL patterns and HTTP method semantics, comprehensive OpenAPI/Swagger documentation generated from code (always up-to-date, never out of sync), authentication and authorization (OAuth2, JWT, API keys) with proper token lifecycle management, pagination, filtering, sorting, and field selection for efficient data retrieval, rate limiting and throttling to protect against abuse and ensure fair usage, and versioning strategy (URL-based or header-based) for backward-compatible evolution. We build APIs in Node.js, PHP/Symfony, Python/FastAPI, .NET, and Java/Spring Boot — choosing the technology that best fits your performance requirements, team expertise, and existing infrastructure.
GraphQL API Development
We build GraphQL APIs for applications that need flexible, efficient data fetching — particularly useful for mobile apps with limited bandwidth, dashboards with complex data requirements, and products where frontend teams need to iterate rapidly without waiting for backend changes. Our GraphQL implementations include schema-first design with strongly typed queries, mutations, and subscriptions, DataLoader pattern for solving the N+1 query problem that plagues naive GraphQL implementations, persisted queries for production security (prevent arbitrary queries from untrusted clients), real-time subscriptions via WebSockets for live dashboards, notifications, and collaborative features, and federation architecture for organizations with multiple teams contributing to a unified API graph. We implement GraphQL on top of existing REST APIs (gateway pattern) or as a native data layer connected directly to your databases and services.
API Integration Services
We connect your application with the external services your business depends on — payment processors (Stripe, PayPal, Adyen), identity providers (Auth0, Okta, Azure AD), communication platforms (Twilio, SendGrid, Slack), cloud services (AWS S3, Google Maps, OpenAI), and industry-specific APIs (banking APIs, healthcare FHIR, logistics tracking). Our integration approach prioritizes resilience: circuit breakers that prevent cascading failures when external services go down, retry logic with exponential backoff for transient errors, webhook verification and idempotency for reliable event processing, request/response logging for debugging and audit compliance, and integration monitoring dashboards showing availability, latency, and error rates for every external dependency.
API Security
We implement API security that protects your data and your users: OAuth2/OIDC flows for secure authentication, JWT token management with proper signing, expiration, and refresh mechanisms, API key management with rotation policies and usage tracking, input validation and sanitization to prevent injection attacks, rate limiting per user/IP/API key to prevent abuse, CORS configuration for browser-based access control, and request signing for webhook verification. For APIs handling sensitive data (financial, healthcare, personal), we implement encryption in transit (TLS 1.3), field-level encryption for PII, audit logging of all data access, and compliance with relevant regulations (GDPR, HIPAA, PCI DSS).
API Testing & Documentation
APIs are contracts — and contracts must be verified and documented. We implement comprehensive API testing: unit tests for individual endpoints, integration tests for multi-service workflows, contract tests (Pact) to verify API compatibility between services, performance tests (k6, Artillery) to validate throughput and latency under load, and security tests (OWASP ZAP) to identify vulnerabilities. Our API documentation is generated automatically from code annotations (OpenAPI/Swagger for REST, GraphQL Playground for GraphQL), includes interactive "Try It" features for developer onboarding, and is published to a developer portal with authentication, code samples in multiple languages, and changelog tracking.
API Gateway & Management
We set up API gateways (Kong, AWS API Gateway, Azure API Management) that provide a unified entry point for all your APIs: request routing to appropriate backend services, authentication and authorization enforcement at the edge, rate limiting and quota management per client/plan, request/response transformation for legacy backend compatibility, caching for frequently accessed resources, analytics and monitoring dashboards showing usage patterns and error rates, and developer portal with self-service API key registration and documentation. For organizations managing multiple APIs (internal + partner + public), we implement API lifecycle management including versioning, deprecation policies, and migration guides.
How We Work
API Design
Define resources, endpoints, data models, and authentication strategy.
Documentation
Create OpenAPI/Swagger specs before implementation.
Development
Implement APIs with proper error handling and validation.
Testing
Unit tests, integration tests, and contract testing.
Deployment
API gateway setup, versioning, and monitoring.
Maintenance
Versioning strategy, deprecation, and ongoing support.
Results You Can Expect
Average API response time with optimized architecture.
Highly available APIs with proper redundancy.
Interactive API docs with code examples in multiple languages.
Technologies & Tools
Frequently Asked Questions
REST is ideal for simple CRUD operations, public APIs, and when caching is important. GraphQL excels when clients need flexible queries, you have multiple frontend clients, or you want to reduce over-fetching. We often use both in the same system for different use cases.
We implement: OAuth 2.0/JWT authentication, API key management, rate limiting, input validation, CORS configuration, HTTPS enforcement, and request/response encryption. We also conduct security testing on all APIs.
Yes, comprehensive documentation is standard. We create OpenAPI/Swagger specs with interactive testing, code examples in multiple languages, authentication guides, and error reference. Documentation is generated from code to stay always up-to-date.
Yes, we regularly integrate with payment gateways (Stripe, PayPal), CRM systems (Salesforce, HubSpot), communication platforms (Twilio, SendGrid), and hundreds of other third-party services.
We implement proper API versioning from the start — typically URL-based (v1, v2) or header-based versioning. This ensures backward compatibility and smooth transitions when APIs evolve.
Ready to Start?Let's Discuss Your Project
Whether you need a dedicated team, a single specialist, or a complete digital transformation — we're here to help.
Or email us directly: [email protected]