Senior .NET Backend / API Integration Engineer

AVENSYS CONSULTING INC.; Quezon City; On-site; PHP 1,800,000 - 2,900,000; Full time

Job summary

AVENSYS CONSULTING INC. is seeking an experienced Senior .NET Backend / API Integration Engineer to lead the design, build and maintenance of backend services and the orchestration layer in a healthcare conversational AI program.

You will route provider calls across authentication, third-party voice and AI agents, with live-agent escalation when needed. You will own technical design of backend services using ASP.NET Core, C#, EF, and lead a team through API development, security and integration

Qualifications

• 8+ years of software development using .NET technologies with backend focus.
• Hands-on Agile/Scrum and AI-Driven Development Lifecycle (AIDLC) experience.
• Proficiency in C#, ASP.NET Core, Web API, and Entity Framework; strong API development and microservices experience.
• Experience designing orchestration/routing layers coordinating multiple services or agents.
• Experience consuming RESTful APIs, webhooks and real-time or streaming interfaces (WebSockets).
• Knowledge of API security standards including OAuth 2.0 and JWT.
• Experience leading or mentoring development teams and owning technical delivery.
• Basic understanding of AI concepts and AI-powered applications (e.g., GitHub Copilot, Claude).

Responsibilities

• Own the technical design of backend services and the orchestration layer using ASP.NET Core, C#, and EF.
• Build and maintain an orchestration and routing layer that manages several voice and AI agents, including hand-offs within a single call.
• Design, develop, secure and maintain RESTful APIs for internal and external integrations with third-party platforms.
• Develop and support API authentication and authorization.
• Provide technical leadership: mentor engineers, set coding standards, lead code reviews.
• Collaborate with Architects on solution design, decisions and estimates.
• Write clean, scalable, well-documented code following best practices.
• Collaborate with Product Owners, QA, DevOps and business teams; drive CI practices.
• Troubleshoot and resolve production issues and improve performance.

Skills

Backend development

API integration

Microservices

Agile/Scrum

AIDLC

Mentoring

API security

Web API

Tools

ASP.NET Core

C#

Entity Framework

RESTful APIs

OAuth 2.0

JWT

Job description

We're looking for an experienced self-driven Senior .NET Backend / API Integration Engineer for a healthcare conversational AI program in Agile / AIDLC working client environment. You'll lead the design, build and maintenance of the backend services and orchestration layer that route provider calls between authentication, multiple third-party voice and AI agents and live-agent escalation.

Primary Responsibilities

• Own the technical design of backend services and the orchestration layer using ASP.NET Core, C#, and Entity Framework.
• Build and maintain an orchestration and routing layer that manages several voice and AI agents, including hand-offs within a single call.
• Design, develop, secure and maintain RESTful APIs for internal and external integrations.
  Integrate with third-party conversational AI and voice platforms, contact center/IVR systems and enterprise healthcare platforms.
• Develop and support API authentication and authorization
• Provide technical leadership: guide and mentor engineers, set coding standards and lead code reviews.
• Work with Architects on solution design, technical decisions and estimates.
• Write clean, scalable, well-documented code that follows best practices.
• Collaborate with Product Owners, QA Engineers, Architects, DevOps and contact center business teams.
• Drive unit testing and continuous integration practices.
• Troubleshoot and resolve complex production issues and improve performance.

Must Haves:

• 8+ years of software development using .NET technologies, with a strong backend focus.
• Hands-on experience with Agile/Scrum and the AI-Driven Development Lifecycle (AIDLC), using AI-assisted tools in the client's environment.
• Proficiency in C#, ASP.NET Core, Web API, and Entity Framework.
  Strong hands-on experience in API development, API integration and microservices architecture.
• Proven experience designing orchestration or routing layers that coordinate multiple services or agents.
  Experience designing and consuming RESTful APIs, webhooks and real-time or streaming interfaces (e.g., WebSockets).
• Knowledge of API security standards, including OAuth 2.0, JWT, authentication and authorization.
• Experience leading or mentoring development teams and owning technical delivery.
• Basic understanding of AI concepts and AI-powered applications – Github Copilot , Claude etc..

Nice to Have

• Contact center or IVR integration experience (call transfer, caller authentication, live-agent escalation).
• Experience consuming LLM or AI agent APIs and applying guardrails (e.g., Azure OpenAI, Semantic Kernel).
• Event-driven integration using Azure Service Bus, Kafka, or similar.