API Backend Engineer (.NET Core) at a Digital Banking Solutions Company - Stretch-it Concepts Limited

Stretch-It Concepts Limited - Our client is a digital banking solutions company building a modern Core Banking API Engine that powers Internet Banking (IB), Corporate/Institutional Banking (CIB), and fintech integrations. Our mission is to deliver secure, scalable, and high-performance APIs that drive innovation in financial services.

They are recruiting to fill the position below:

Job Title: API Backend Engineer (.NET Core)

Location: Lagos / Hybrid
Reports To: Lead Engineer API Management
Employment Type: Full-time

Role Overview

• We are looking for an experienced API Backend Engineer with strong skills in .NET Core to design and develop the backend services and APIs for Finedge’s Core Banking API Engine.
• You will build secure and reliable microservices, integrate with core banking systems, and ensure high performance to support mission-critical financial operations.

Key Responsibilities
API Development:

• Design, develop, and maintain RESTful APIs and microservices using .NET Core (C#).
• Implement business logic for core banking features: account management, payments, loans, treasury, and compliance.
• Define and enforce API standards (OpenAPI/Swagger, JSON, gRPC).
• Build scalable backend services that support high transaction volumes and low-latency operations.
• Integrate APIs with core banking systems (Finedge, Flexcube, Finacle, Temenos, or custom engines).

Backend Engineering:

• Work with SQL Server, PostgreSQL, and NoSQL databases to ensure efficient data modeling and transactions.
• Implement caching, queuing, and asynchronous processing for performance optimization.
• Ensure fault tolerance, resilience, and backward compatibility of APIs.
• Collaborate with architects to evolve a microservices-based architecture.

Security & Compliance:

• Apply secure coding practices and adhere to OWASP API Security Top 10.
• Implement authentication and authorization using OAuth2, OpenID Connect, JWT.
• Support compliance with PCI-DSS, GDPR, ISO 27001, and banking regulations.

Collaboration & Process:

• Work with frontend/mobile engineers to expose banking features via APIs.
• Collaborate with DevOps engineers on CI/CD pipelines and containerized deployments.
• Participate in Agile ceremonies, sprint planning, and technical reviews.
• Write and maintain API documentation for internal and external developers.

Requirements

• Bachelor’s Degree in Computer Science, Software Engineering, or related field.
• 3–5+ years of experience in backend development with .NET Core (C#).
• Strong understanding of REST API design, microservices, and distributed systems.
• Experience with databases (SQL Server, PostgreSQL, MongoDB, Redis).
• Familiarity with message brokers (Kafka, RabbitMQ, Azure Service Bus).
• Knowledge of API testing frameworks (Postman, Swagger, xUnit, NUnit).
• Good understanding of scalability, performance tuning, and high-availability design.
• Proficiency with Git and Agile methodologies.

Preferred Skills:

• Experience in core banking systems (Temenos, Finacle, Flexcube, or similar) is an added advantage
• Exposure to Open Banking & ISO 20022 standards.
• Familiarity with cloud platforms (Azure preferred, AWS/GCP).
• Knowledge of API gateways (Kong, Apigee, Azure API Management).
• Experience in event-driven architecture and CQRS patterns.

Application Closing Date
15th November, 2025.

How to Apply
Interested and qualified candidates should send their CV to: jobs@stretchitconcepts.com using "Application – API Backend Engineer (.NET Core)" as the subject of the mail.