4
applicants

Senior Software Engineer – API Development

VS ONE WORLD (Pvt) Ltd    Colombo • Full-time

Join VS One World and help build secure, scalable, and high-performance API solutions. If you have 3–5 years of experience in backend development, microservices, cloud technologies, and API integration, we'd love to hear from you.

Required Skills:

1. Programming & Language Depth

  • Strong proficiency in at least one backend language (Java, Node.js, Go, Python, C#) - not just syntax, but idiomatic use, concurrency models, and performance characteristics.
  • Solid grasp of OOP/functional principles, data structures, and algorithms.

2. API Design & Architecture

  • RESTful API design principles (resource modeling, status codes, idempotency, versioning strategies).
  • Understanding of when to use REST vs GraphQL vs gRPC vs event-driven/async APIs.
  • Microservices architecture patterns: service decomposition, bounded contexts, inter-service communication (sync vs async).
  • API contract-first design (OpenAPI/Swagger spec-driven development).

3. Data & Persistence

  • SQL and at least one NoSQL store (MongoDB, DynamoDB, Redis).
  • Schema design, indexing, query optimization, transaction management across services (sagas, eventual consistency).

4. Middleware & Integration

  • Message brokers/event streaming (Kafka, RabbitMQ, SQS).
  • API gateways and management platforms (WSO2 APIM, Kong, Apigee).
  • Understanding of middleware patterns: circuit breakers, retries, rate limiting, caching.

5. Security

  • AuthN/AuthZ: OAuth2, OIDC, JWT.
  • Input validation, encryption in transit/at rest, secrets management.
  • Common API vulnerabilities (OWASP API Top 10).

6. Testing

  • Unit and integration testing frameworks.
  • API test automation (Postman/Newman, REST Assured).
  • Contract testing (Pact) for microservices.

7. DevOps & Operations

  • Basic cloud platform exposure (AWS/GCP/Azure).

8. Documentation & Collaboration

  • Swagger / OpenAPI spec writing.
  • Clear technical communication for cross-team API consumers.

9. Increasingly Valued (AI Era)

As VS One World builds Al capability, exposure to designing APIs that front LLM/RAG services (streaming responses, token- based rate limiting, prompt/response logging) is becoming a differentiator - even if not yet core to a traditional API developer role.

Added advantage: Experience with WSO2 API Manager (APIM) and Identity Server (IS).