Senior Software Engineer in Test

Company Overview Mainspring Energy is revolutionizing power generation with the world’s most flexible and adaptable local power generation technology, the Mainspring Linear Generator. Commercial, industrial, and utility leaders are choosing Mainspring over traditional options like engines, turbines, and fuel cells to quickly and reliably deliver local power for EV charging, commercial facilities, data centers, and grid-scale operations. The Mainspring Linear Generator is fuel flexible, ramps up and down to meet demand, and utilizes a flameless reaction with near-zero NOx emissions. Backed by top-tier investors including Khosla Ventures, Bill Gates, American Electric Power, Lightrock, and General Catalyst Mainspring designs, manufactures and delivers its products to customers across the U.S. today, and we’re quickly scaling for international expansion. Inspired by our vision of the affordable, reliable, net-zero carbon grid, Mainspring is rapidly expanding within the $816B global electricity equipment market, and we’re hiring the best talent to meet growing customer demand around the globe. We welcome a broad range of backgrounds, experiences, and talents to bring fresh perspectives and ongoing innovation to our customers. We are looking to build relationships with people who share our values: Pragmatic Optimism. Building a new category of world-class power generation requires the optimism of ambition and creativity, balanced with practicality to solve problems efficiently. The challenges that arise are opportunities for growth. Excellence without Ego. We bring expertise and commitment to creating the best customer experience, from sales to deployment and service, just as we apply deep technical rigor to building and delivering world-class products. We strive for excellence and behave as leaders with the humility to acknowledge our challenges, both collectively and as individual contributors. Proactive Collaboration. The integration and cross-disciplinary nature of Mainspring’s business requires intentionally seeking out others who bring different skills, perspectives, and priorities. Our culture of inclusion and respect extends beyond our team to interactions with our partners and customers. More information can be found at www.mainspringenergy.com Job Overview Do you enjoy diving into building new automation systems and formulating new testing approaches in areas like cloud computing, networking, IoT with real time operating systems, controls, simulations (MIL, SIL, PIL), and algorithms? We combine this technology with our company vision of building a new category of power that is affordable, reliable, and targeting a net-zero carbon grid. This cornucopia of science and technology will be your daily career at Mainspring. This is an opportunity for you to join a world-class engineering team: to build and run automated testing systems to ensure the quality of the product. This is an exciting opportunity to become part of a rapidly growing engineering team. In this role. you will have significant influence over the quality of the product, engage with developers to understand new features and technologies, and create innovative automated testing solutions within tight requirements to solve complex scenarios with multiple components. Does your experience not meet all of our posted requirements? Studies have shown that some people are less likely to apply to positions unless they meet every listed requirement. At Mainspring, we are committed to building a diverse, inclusive, flexible, and collaborative environment, so if you want to help us transition the world to clean and affordable electricity, and don’t meet all posted requirements for a particular role, we’d still love to hear from you. Mainspring can sometimes be flexible enough to shift responsibilities for the right person, or otherwise identify open or upcoming roles that may better fit your professional background. In more traditional words, Mainspring Energy, Inc is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, or protected veteran status and will not be discriminated against on the basis of disability. This compensation and benefits information is based on Mainspring Energy's estimate as of the date of publication and may be modified in the future. We generally do not negotiate on salary once we have made an offer. The level of pay within the range will depend on a variety of job-related factors that may include location, relevant prior experience and/or education, or particular skills and expertise. New hires joining the company tend to be paid within the starting base pay range noted above, with opportunities to increase pay over time based on development of additional skills, competencies, and company-specific knowledge. Responsibilities Architect Automation: Design and scale robust test frameworks and CI/CD integrations System Validation: Create workflows to validate complex hardware/software integrations and resolve system-level bottlenecks Root Cause Analysis: Lead failure analysis and risk mitigation to ensure test stability and environment reliability Strategic Coverage: Drive risk-based testing strategies to ensure comprehensive coverage of all critical-path functionalities Qualifications Experience & Education: Bachelor’s degree in Computer Science or a related field with 6+ years of professional experience, or a Master’s degree with 5+ years in an SDET or Software Engineering role Engineering Mindset: A driven, self-directed contributor who views test infrastructure as a first-class product; you thrive on architecting scalable, automated systems that increase developer velocity Strategic Test Design: Proven track record of leading complex automation projects from design to implementation, with the foundational ability to perform deep-dive manual exploratory testing and technical test case design Technical Versatility: Strong hands-on experience developing in Python and C++, with the flexibility to navigate and contribute to diverse codebases as the project requires AI Workflow Ownership: Demonstrated proficiency in leveraging AI coding assistants as a force multiplier for productivity, combined with the professional judgment to challenge and expand upon AI-generated solutions to ensure system integrity and long-term maintainability

{
  "content_hash": "a1c7863b275326d2bb8154e7d6aadc20939ad770070bbcfb510f911b7126f37b",
  "source_hash": "01e3fa79e99b5ccbfb855d9665029882b9bfde750da85c329fc7a913e384b2d5",
  "last_changed_at": "2026-05-29T07:06:04.955Z",
  "active_status": "active"
}

{
  "language": "en",
  "location": {
    "raw": "Menlo Park, CA",
    "city": "Menlo Park",
    "region": "CA",
    "country": "United States",
    "is_remote": false,
    "confidence": 0.9
  },
  "salary_max": 145000,
  "salary_min": 123400,
  "inferred_at": "2026-06-06T07:57:07.972Z",
  "launch_scope": {
    "reason": "english_us_canada",
    "included": true,
    "language": "en",
    "location": {
      "raw": "Menlo Park, CA",
      "city": "Menlo Park",
      "region": "CA",
      "country": "United States",
      "is_remote": false,
      "confidence": 0.9
    },
    "countries": [
      "United States"
    ]
  },
  "remote_policy": null,
  "salary_period": "year",
  "workplace_type": "on_site",
  "salary_currency": "USD"
}

{}

{
  "lists": [
    {
      "text": "Responsibilities",
      "content": "<div>\n\n<li>\n<p>Architect Automation: Design and scale robust test frameworks and CI/CD integrations</p>\n</li>\n<li>\n<p>System Validation: Create workflows to validate complex hardware/software integrations and resolve system-level bottlenecks</p>\n</li>\n<li>\n<p>Root Cause Analysis: Lead failure analysis and risk mitigation to ensure test stability and environment reliability</p>\n</li>\n<li>\n<p>Strategic Coverage: Drive risk-based testing strategies to ensure comprehensive coverage of all critical-path functionalities</p>\n</li>\n\n</div>"
    },
    {
      "text": "Qualifications",
      "content": "<div>\n\n<li>\n<p>Experience &amp; Education: Bachelor’s degree in Computer Science or a related field with 6+ years of professional experience, or a Master’s degree with 5+ years in an SDET or Software Engineering role</p>\n</li>\n<li>\n<p>Engineering Mindset: A driven, self-directed contributor who views test infrastructure as a first-class product; you thrive on architecting scalable, automated systems that increase developer velocity</p>\n</li>\n<li>\n<p>Strategic Test Design: Proven track record of leading complex automation projects from design to implementation, with the foundational ability to perform deep-dive manual exploratory testing and technical test case design</p>\n</li>\n<li>\n<p>Technical Versatility: Strong hands-on experience developing in Python and C++, with the flexibility to navigate and contribute to diverse codebases as the project requires</p>\n</li>\n<li>\n<p>AI Workflow Ownership: Demonstrated proficiency in leveraging AI coding assistants as a force multiplier for productivity, combined with the professional judgment to challenge and expand upon AI-generated solutions to ensure system integrity and long-term maintainability</p>\n</li>\n\n</div>"
    }
  ],
  "country": "US",
  "createdAt": 1778703635524,
  "updatedAt": null,
  "categories": {
    "team": "On product SW and Sys Engr",
    "location": "Menlo Park, CA",
    "commitment": "Salary",
    "department": "On product SW and Sys Engr",
    "allLocations": [
      "Menlo Park, CA"
    ]
  },
  "salaryRange": {
    "max": 145000,
    "min": 123400,
    "currency": "USD",
    "interval": "per-year-salary"
  },
  "workplaceType": "onsite"
}