Demo

Senior Software Engineer -API

MARS Solutions Group
Milwaukee, WI Contractor
POSTED ON 4/20/2026
AVAILABLE BEFORE 5/20/2026
MARS Solutions Group is looking for an experienced Senior Software Engineer. Our client is an insurance firm looking for high-quality talent to make a difference. They are known to respect a traditional work week and often extend contracts for added job security and stability.

What's the Role?

Collaborate with the API Enablement team to build and maintain enterprise-grade internal tooling, API governance automation, and developer experience platforms. Contributes to the design and delivery of cross-cutting technical solutions — including API quality enforcement engines, SDK generators, and the enterprise API catalog — that enable domain teams to build and publish high-quality APIs at speed. Supports contract-first API development practices and tooling built around OpenAPI Specification (OAS). Participates in refinement, solution definition, and decomposition of features into deliverable work items. Works across organizational boundaries with domain engineering teams, Enterprise Architecture, and API Management to deliver on the team's highest-priority initiatives. Finds opportunities for continuous improvement and owns initiatives that help the team get better. Engages collaboratively, respects diverse perspectives, and communicates effectively with both technical and non-technical audiences.

Qualifications

  • Bachelor's Degree or equivalent experience
  • 8 years of professional software development experience required
  • 5 years of experience with API design, development, and governance including OpenAPI Specification (OAS) and REST best practices
  • Experience with Java and/or Node.js/TypeScript
  • Proficient in practices such as contract-first API design, API quality automation, and internal platform/tooling development
  • Proven track record of architecting and delivering significant developer tooling or platform solutions (e.g., SDK generators, compliance engines, API catalogs)
  • Capable of working autonomously and delivering with minimal direction in an enterprise environment
  • Effective communicator with product, engineering, architecture, and business partners, with proven ability to communicate to both technical and non-technical audiences in varying forms and levels of detail

Skills for Sourcing

Must-Have Skills

API Development (REST / OpenAPI), Java or Node.js/TypeScript, Internal Developer Tooling / Platform Engineering, Contract-First API Design

Nice-to-Have Skills

API Quality / Compliance Automation (e.g., Spectral), Client SDK Generation (e.g., OpenAPI Generator / Kiota), API Catalog / Developer Portal Experience, Enterprise Authorization Patterns (PBAC or similar)

About MARS Solutions Group: MARS Solutions Group provides a range of opportunities for meaningful work by understanding that employment fit is a combination of people, process, and technology. We leverage our experienced and compassionate team to bring humanity to matching you with the right advanced technology role, and stay connected with you to help you attain your professional goals.

Salary : $70 - $71

If your compensation planning software is too rigid to deploy winning incentive strategies, it’s time to find an adaptable solution. Compensation Planning
Enhance your organization's compensation strategy with salary data sets that HR and team managers can use to pay your staff right. Surveys & Data Sets

What is the career path for a Senior Software Engineer -API?

Sign up to receive alerts about other jobs on the Senior Software Engineer -API career path by checking the boxes next to the positions that interest you.
Income Estimation: 
$123,167 - $152,295
Income Estimation: 
$146,673 - $180,130
Income Estimation: 
$146,673 - $180,130
Income Estimation: 
$176,149 - $220,529
Employees: Get a Salary Increase
View Core, Job Family, and Industry Job Skills and Competency Data for more than 15,000 Job Titles Skills Library

Job openings at MARS Solutions Group

  • MARS Solutions Group Wisconsin, WI
  • Position Title: Electrical / Controls Engineer – Industrial Automation Location: Wisconsin Duration: Direct Hire Schedule: 40 hours/week Shift hours: Mon –... more
  • 12 Days Ago

  • MARS Solutions Group Charlotte, NC
  • MARS Solutions Group is looking for an experienced Oracle Finance Systems Lead . Our client is a Wealth Management firm looking for high-quality talent to ... more
  • 1 Day Ago

  • MARS Solutions Group Milwaukee, WI
  • MARS Solutions Group is looking for an experienced IT Project Manager located in Milwaukee, WI . Our client is a leading electric and natural gas utility i... more
  • 4 Days Ago

  • MARS Solutions Group Milwaukee, WI
  • MARS Solutions Group is looking for an experienced Senior Audio Visual Design Engineer . Our client is an insurance firm looking for high-quality talent to... more
  • 4 Days Ago


Not the job you're looking for? Here are some other Senior Software Engineer -API jobs in the Milwaukee, WI area that may be a better fit.

  • API Heat Transfer Franklin, WI
  • As a global leader in the design and manufacture of a wide range of specialty heat exchangers and heat transfer solutions, API Heat Transfer has a legacy o... more
  • 4 Days Ago

  • API Heat Transfer Franklin, WI
  • As a global leader in the design and manufacture of a wide range of specialty heat exchangers and heat transfer solutions, API Heat Transfer has a legacy o... more
  • 11 Days Ago

AI Assistant is available now!

Feel free to start your new journey!