Test Engineer

Job Posting Start Date 02-11-2026 Job Posting End Date 04-10-2026

At JetCool, a Flex company, we're at the forefront of liquid cooling innovation, delivering advanced solutions that empower our partners in AI and high-performance computing. United by a shared purpose, our teams are pushing the limits of what's possible and tackling complex challenges.

A career at JetCool offers the opportunity to make a real impact by helping build smarter, more sustainable data centers. Together, we're not just advancing technology - we're redefining cooling standards to create a more sustainable tomorrow.

Job Summary

To support our extraordinary teams who build great products and contribute to our growth, we're looking to add a Test Engineer located in Littleton, MA.

Reporting to the Product Manager the Test Engineer will execute and analyze the data of experiments driving performance improvements and demonstrating reliability. The position will be responsible for the development of test plans, leading the assembly of test beds and execution and analysis of the planned test sequences. Successful candidates will be comfortable taking on tasks as an individual contributor as well as working together with the team as required to meet project deadlines.

What a typical day looks like:

• Apply first principles in fluid dynamics and heat transfer to design rigorous experiments to verify product specifications and design features / performance
• Document detailed test plans to ensure test and product evaluation goals are met
• Lead design and manufacture of test beds
• Perform test assembly and instrumentation of designed experiments
• Execute test sequences and analyze the resulting data
• Effectively document and communicate results
• Provide DFM (design for manufacture), DFA (design for assembly) and performance design optimization feedback to design and manufacturing teams.
• Bachelor of Science (B.S. in mechanical or aerospace engineering)
• Ability to balance and prioritize multiple simultaneous projects
• Comfortable with basic plumbing and assembly techniques
• Familiarity with sensors and instrumentation and their data acquisition
• Good first principles knowledge in fluid dynamics, thermodynamics, and heat transfer
• Demonstrated ability with hands-on builds/projects
• Ability to work independently and on small teams
• Proficiency in a CAD and drawing package
• Comfortable with data analysis using MS Excel, Matlab (Octave), or similar tools

The experience we're looking to add to our team:

• 3 years of experience in mechanical engineering or aerospace engineering
• Comfortable with data acquisition hardware programming (e.g. Labview, Python / Labjack, etc.)
• Proficiency in Solidworks
• Industry experience in fluid system, compute, or electric vehicle applications
• Six Sigma certification(s) (Green belt, etc.)
• Savvy with electronics systems and/or electronics packaging
• Experience with product development cycles involving environmental and reliability test campaigns
• Comfortable in a fast-paced, technology startup
• Industry experience in aerospace/defense, automotive, or data centers

BO18

What you'll receive for the great work you provide:

• Full range of medical, dental, and vision plans
• Life Insurance
• Short-term and Long-term Disability
• Matching 401(k) Contributions
• Vacation and Paid Sick Time
• Tuition Reimbursement

Pay Range (Applicable to Massachusetts)

$96,400.00 USD - $132,500.00 USD Annual

Job Category
Production Engineering

Is Sponsorship Available?
No

JetCool is an Equal Opportunity Employer and employment selection decisions are based on merit, qualifications, and abilities. We do not discriminate based on: age, race, religion, color, sex, national origin, marital status, sexual orientation, gender identity, veteran status, disability, pregnancy status, or any other status protected by law. We're happy to provide reasonable accommodations to those with a disability for assistance in the application process. Please email accessibility@flex.com and we'll discuss your specific situation and next steps (NOTE: this email does not accept or consider resumes or applications. This is only for disability assistance. To be considered for a position at JetCool, you must complete the application process first).

Client-provided location(s): Boxborough, MA

Job ID: Flex-WD214696

Employment Type: FULL_TIME

Posted: 2026-02-12T19:38:31