Freelance Simulation Software Engineer Jobs in California

Zipline is scaling the world's largest autonomous drone delivery network—a pioneering Physical AI system—delivering life-saving medical supplies and commercial goods globally. Our commitment to safety and exponential scale demands an industrial-grade virtual test environment, decoupled from physical hardware. That's the mission of our Simulation team.

We are seeking a Simulation Software Engineer to build and evolve the core infrastructure that validates our entire robotics fleet software. This is not a standard simulation role; it is deep, systems-level software engineering focused on creating high-performance, high-fidelity digital twins that enable deterministic, faster-than-realtime testing of all autonomous safety-critical flight logic, cloud connectivity, and vehicle coordination across thousands of mission scenarios.

This role is absolutely critical for the safety and reliability of Zipline's real-world Physical AI deployment. If you are driven by the challenge of integrating complex flight software with synthetic environments, real hardware, and advanced time-manipulation to rigorously test an autonomous system, we want to hear from you!

This is not a niche role within Autonomy—it's a company-wide enabler.

If your passion lies in building infrastructure that unlocks fast, safe iteration across multiple engineering domains, this role is built for you.

• Build the simulation platform: Develop the reusable infrastructure that powers simulation across the company, including execution, scheduling, orchestration, APIs, and developer tooling.
• Integrate with production software: Build interfaces that allow flight software, cloud services, embedded software, and hardware to execute inside deterministic virtual environments.
• Scale simulation: Scale from single-vehicle debugging to fleet-scale testing across thousands of scenarios in CI.
• Partner with engineers: Support teams building new tests, debugging failures, improving workflows, and expanding simulation capabilities.

• The Flight Software team uses simulation to validate onboard mission logic.
• The Test team uses it to explore pre-flight conditions and troubleshoot real-world anomalies.
• The Cloud team uses it to model server interactions like map updates, delivery instructions, and real-time comms.
• Full system Hardware-In-The-Loop testing framework uses simulation for flight software validation
• The Embedded and Ground teams use it to validate system integration, safety cases, and operational resilience.
• And the CI/CD pipeline relies on simulation to catch regressions before they ever reach a flight zone.

• 4+ years of professional software engineering experience in C++ or Rust (Rust experience is a strong plus).
• Demonstrated ability to reason about large software systems, APIs, concurrency, debugging, and software architecture.
• Deep experience architecting, building, or maintaining complex robotics, aerospace, or distributed systems simulations/digital twins.
• Expertise in concepts like time synchronization, inter-process communication, and determinism within a systems-level or real-time context.
• Familiarity with physical modeling, kinematics, dynamics, or robotics simulation concepts
• A passion for building enabling infrastructure and tools that allow Zipline engineers to simulate faster, test earlier, and deploy safer.
• Bonus: Experience scaling simulation in CI, HIL (Hardware-in-the-Loop), or formal verification methods.

• This role is onsite in the Bay Area due to frequent cross‑functional collaboration, access to flight test and HIL labs, and operational incident response.
• Occasional travel to field sites or test ranges may be required.
• Must be eligible to work in the US

The starting cash range for this role is $180,000 - $220,000. 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.

Zipline is an equal opportunity employer and prohibits discrimination and harassment of any type without regard to race, color, religion, age, sex, national origin, disability status, genetics, protected veteran status, sexual orientation, gender identity or expression, or any other characteristic protected by federal, state or local laws or our own sensibilities.

We value diversity at Zipline and welcome applications from those who are traditionally underrepresented in tech. If you like the sound of this position but are not sure if you are the perfect fit, please apply!