.NET API Software Consultant

Emerald Resource Group; Cleveland (OH); On-site; USD 140,000 - 200,000; Full time

Job summary

Emerald Resource Group is seeking a Senior .NET API Software Consultant for a 12-month on-site engagement in Northeast Ohio or Columbus. You will review the current monolithic API, validate architecture, and predominantly build the new API layer with a focus on enterprise-grade design, security, and performance.

The role centers on C#/.NET, SQL Server, OAuth2/OIDC, and Azure API Management, with potential extension based on project success.

Qualifications

• Enterprise API design and development experience.
• API modernization and secure, token-based auth (OAuth2/OIDC).
• Deep experience with C#/.NET, SQL Server, and API gateways.
• Ability to review architecture upfront and then implement APIs.

Responsibilities

• Review and validate initial API architecture and roadmaps.
• Build and secure the new API layer on top of the legacy system.
• Deliver enterprise-grade APIs with robust error handling and scalability.
• Collaborate with stakeholders in Northeast Ohio or Columbus, OH.

Skills

API design

.NET

OAuth2/OIDC

Azure API Management

SQL Server

Tools

Azure

SQL Server

Job description

If you're a senior .NET engineer who really knows APIs, this is a project worth looking at.

I'm working on a consulting opportunity for a company that currently has one large monolithic API and is building what comes next.

A few important details upfront for the .NET API Software Consultant

• Must currently live in Northeast Ohio or the Columbus, Ohio area
• No C2C or third-party candidates
• Initial 12-month consulting engagement with strong potential to extend

Much of the direction and design for the new API layer has already been established. They need a senior engineer who can come in, review and validate some of the architecture upfront, but then spend the majority of their time actually building the new APIs.

That's really the heart of this project.

The environment is heavily C#/.NET and SQL Server, and we're looking for someone who has gone deep into enterprise API development.

Some of the experience that will matter for the .NET API Software Consultant:

• Enterprise API design and development
• API modernization
• OAuth2 / OIDC and delegated authentication
• Azure API Management and gateway policies
• SQL Server and database-heavy backend logic
• Secure, transaction-oriented APIs

There's also an interesting second phase to this project.

Once the API foundation is built, AI becomes a much bigger part of where they're headed. The APIs will ultimately help provide a secure way for AI-powered applications and agents to interact with existing business systems and data.

So this isn't really an "AI Engineer" opening.

They're looking for a strong senior API/backend engineer who understands that you have to build the foundation correctly before you put AI on top of it.

If you've built secure enterprise APIs and like the idea of helping build a new API layer rather than spending the next year maintaining an old one, I'd like to talk.