Senior / Staff Mechanical Engineer, Dropbox

About You and The Role

Zipline builds and operates autonomous delivery systems that move critical goods reliably and safely. Dropbox is our customer-facing package-loading product that integrates mechatronics, sensors, electronics, access control, user interaction, and environmental protection so untrained users can hand off packages to our droids. Failures or slow service at Dropbox directly increase field escalations, maintenance cost, and delivery delays—this role changes fleet uptime and customer trust.

As a Senior Mechanical Engineer on Dropbox, you will own the mechanical architecture and detailed design of key assemblies through validation, production ramp, and fleet operation. You will make architecture-level tradeoffs that balance safety, reliability, manufacturability, and serviceability for an unattended field-facing product. This is a hands-on, individual-contributor role responsible for designs that must meet high-cycle life, environmental exposure, and low-maintenance targets in real-world sites.

What You'll Do

• Own end-to-end mechanical scope for Dropbox assemblies: requirements, architecture, detailed CAD, drawings, specifications, BOMs, and production release.
• Define success metrics for your systems (e.g., target field MTBF, service MTTR, production yield, or mean time between service actions) and drive design choices to meet them.
• Translate customer workflows, hazard analyses, and droid interfaces into mechanical requirements and verified designs that minimize field interventions.
• Lead trade studies and system-level decisions across safety, reliability, cycle time, environmental performance, serviceability, DFM, DFA, cost, and schedule; document chosen trade-offs and residual risks.
• Create GD&T, datum strategy, alignment schemes, and tolerance stack-ups across complex electromechanical interfaces to ensure consistent assembly and alignment during high-volume builds.
• Perform and apply first-principles analysis, hand calculations, kinematic analysis, fatigue/wear assessments, and FEA to set margins and validate designs against defined targets.
• Integrate actuators, transmissions, bearings, sensors, PCBAs, connectors, harnesses, seals, and embedded controls into reliable assemblies; define and verify mechanical/electrical interfaces.
• Partner closely with Electrical, Embedded Software, Systems, Test, Reliability, Manufacturing, Operations, and Safety to develop validation plans covering functional, lifetime, environmental, abuse, and fault-condition scenarios.
• Prototype rapidly, run targeted experiments and test campaigns, and use data to down-select concepts and reduce technical risk; own test evidence and acceptance criteria.
• Lead investigations of prototype, production, and field failures: contain, establish root cause, implement corrective actions, and track recurrence reduction metrics.
• Work directly with suppliers, NPI, and Manufacturing to implement DFM/DFA changes, improve yield, and qualify production processes; support supplier qualification and on-site manufacturing troubleshooting.
• Use fleet telemetry, service records, and field observations to prioritize design changes that reduce failure rates and maintenance burden; report measurable improvement in uptime or service events.
• Mentor other engineers, establish mechanical design best practices, and drive improvements in documentation quality and release discipline.

What You'll Bring

• Proven end-to-end ownership of electromechanical hardware through concept, validation, production ramp, and field deployment in customer-facing or unattended systems.
• Deep mechanism and structure design experience (actuators, transmissions, bearings, seals, high-cycle moving assemblies) with demonstrated fatigue, wear, and environmental design competence.
• Strong mechanical fundamentals (hand calculations, FEA grounding, kinematics, bolted joints, materials, tolerance analysis) and advanced CAD skills managing system-level assemblies and drawing releases.
• Demonstrated GD&T mastery, datum strategy, and practical tolerance-stack experience enabling repeatable high-yield assembly.
• Prototyping and test experience; ability to define and run experiments and convert data into design decisions.
• Track record resolving complex or intermittent hardware failures through disciplined root-cause analysis and corrective action implementation.
• Experience integrating PCBAs, wiring harnesses, motors, sensors, and embedded controls into mechanical designs.
• Experience working directly with suppliers and manufacturing to ship high-volume, high-reliability hardware; comfortable leading supplier qualification and on-site problem solving.
• Location & logistics: this role is in-person in South San Francisco with regular on-site collaboration. Expect travel (~10–25% typical) to suppliers, manufacturers, test locations, and deployment sites depending on program needs.
• Operating intensity & constraints: you will work on customer-facing, unattended field systems where rapid escalation, supplier trips, test campaigns, and production-support nights are required to protect fleet uptime; must be comfortable with high-responsibility, hands-on delivery cadence.
• Traits: decisive engineering judgment, clarity in documenting assumptions and risks, rigorous data-driven decision-making, and calm, methodical troubleshooting under field pressure.

What success looks like

• Delivered mechanical releases that meet agreed field reliability targets and ramp to production with ≥ target yield.
• Reduced field service events or mean time to repair for owned assemblies as demonstrated by telemetry and service records.
• Established repeatable validation coverage and supplier processes that shorten failure-to-fix cycles and lower cost per service event.

What Else You Need to Know

The starting cash range for this role is $160,000 - $250,000. Please note that this is a target, starting cash range for a candidate who meets the minimum qualifications for this role. The final cash pay for this role will depend on a variety of factors, including a specific candidate's experience, qualifications, skills, working location, and projected impact. The total compensation package for this role may also include: equity compensation; discretionary annual or performance bonuses; sales incentives; benefits such as medical, dental and vision insurance; paid time off; and more.