Entry Level Mechanical Engineer Startup Jobs in California

Who we are 

Atoms is building the machines that power the next era of progress.

Over the last decade, software has transformed the digital world. But the physical world, where food is made, minerals are mined, goods are moved, and industries are run, remains far less intelligent, far less efficient, and far more constrained. We're changing that.

Atoms builds Physical AI- real-world robots for the industries that move civilization forward, starting with food, mining, and transport. Our systems are designed to understand, predict, and control the real world with precision, turning complex physical operations into something more reliable, more scalable, and more productive.

This work requires more than robotics. It requires deep integration across hardware, software, AI, operations, manufacturing, and real estate. We don't just build machines in a lab. We deploy them into real environments, operate them, learn from them, and improve them until they work at scale.

We are roboticists, engineers, operators, and builders. We believe the next great technology companies will not only transform information, but the physical systems that shape everyday life.

If you want to work on hard problems with real-world impact, join us.

What you'll do

We are seeking a Senior Mechanical Engineer to help design the physical architecture of our next-generation autonomous transport platforms. In this role, you will bridge the gap between industrial design and vehicle production, transforming complex prototypes into scalable realities. You will own the mechanical packaging of safety-critical systems, including structural sensor mounts, ruggedized compute housings, and drive-by-wire integrations. By developing robust engineering documentation and validation procedures, you will ensure our fleet operates safely and reliably in urban environments.

• Sensor & Compute Packaging: Design, package, and integrate advanced autonomous vehicle sensor suites and ruggedized compute housings onto on-road passenger vehicle platforms.
• Drive-by-Wire Integration: Design the electromechanical packaging of drive-by-wire (DBW) actuation systems, custom PCB enclosures, and low-voltage routing.
• Ensure all PCB enclosures meet thermal performance requirements.
• Prototype to Production Scaling: Transform early-stage prototype hardware components into refined, scalable designs optimized for high-volume manufacturing assembly.
• Cross-Functional Collaboration: Partner directly with industrial designers, in-house manufacturing technicians, external vendors, and manufacturing engineering to execute rapid prototype part runs.
• Engineering Documentation: Create and maintain highly disciplined engineering documentation, including complex CAD models, production-ready drawings, Bills of Materials (BOMs), and clear installation manuals.
• Rapid Prototyping Execution: Fabricate and iterate physical mockups using a diverse suite of rapid prototyping methods, ensuring designs are optimized for CNC machining, sheet metal fabrication, and 3D printing.
• Testing & System Validation: Establish and run rigorous physical testing and validation protocols for electromechanical systems to guarantee environmental durability, shock absorption, and long-term reliability.

 

What we're looking for

• Bachelor's degree in Mechanical Engineering, Mechatronics, or a closely related field is required.
• Minimum 2+ years of non-internship professional Mechanical Design Engineering experience.
• Proficient hands-on design experience utilizing 3D CAD modeling software such as SolidWorks, Catia or NX.
• Proven background building, assembling, and troubleshooting complex mechanical, electrical, or structural assemblies.
• Strong knowledge of manufacturing processes, with direct experience designing for CNC machining, sheet metal stamping, and injection molding.
• Prior experience or deep familiarity with the structural integration of hardware onto automotive platforms, mobile robotics, or heavy mechatronic equipment.
• Demonstrated ability to create accurate, production-level engineering drawings and meticulous component documentation using GD&T where applicable
• Exceptional aptitude for navigating ambiguity and collaborating dynamically within a fast-paced, hardware-in-the-loop startup environment.
  

Why join us

At Atoms, you'll work on one of the defining challenges of our time - bringing automation into the physical world to drive real, lasting impact. We exist to uncover valuable unknown truths and turn them into progress, which means constantly pushing beyond what's known and building what doesn't yet exist. The work is ambitious and often challenging, but it's grounded in a shared sense of purpose and a team committed to seeing it through together. Our work only matters if it serves others, and we know that meaningful progress depends on the trust of the people we serve and the strength of our team-so we invest in both, creating an environment where you can do your best work and grow.

What else you need to know

This role is based in our San Francisco office. Atoms is a company driven by invention and continuous change - we are constantly reimagining our industries, building new products, and refining how we operate. We do our best work together. That's why all of our office-based teams work onsite, five days a week.

The base salary range for this role is $114,000 - $280,000 per year. 

Actual compensation will be determined on an individual basis and may vary depending on experience, skills, and qualifications.

Base salary is just one part of your total rewards package. You may also be eligible for equity awards.

Benefits Summary (USA Full-Time Exempt Employees):

• Medical, Dental, Vision, Disability, and Life Insurance
• Flexible Spending Account / Health Savings Account Options
• 401(k)
• Equity
• Sick Time, Unlimited Flexible Time Off, and Paid Holidays
• Paid Parental Leave 
• Pre-Tax Commuter Benefit Plan
• Team lunch in our SoMa office every Tuesday and Thursday

Benefits are subject to change at the company's discretion.
Atoms accepts applications on an ongoing basis.

Ready to join us as we serve those who serve others? 

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