Senior​/Principal Software Engineer

Endurance is building the world's first modular subsea geothermal power plants, converting vast thermal resources under the ocean into gigawatts of baseload power. Backed by Founders Fund, Felicis, First Round Capital, and Point
72 Ventures, our founding team includes veterans from SpaceX, Helion, Blue Origin, and Apple. We have completed multiple deep-ocean deployments to subsea volcanoes and are launching a long‑term demonstration project this fall. By leveraging modular design, manufacturing scale, efficient drilling, and latent cooling on the seafloor, we are pioneering a new category of energy that outperforms traditional sources on environmental impact, deployment speed, and cost.

As a Senior/Principal Software Engineer at Endurance, you will build the software stack, controls, UIs, and simulation infrastructure that allows our engineering team to rapidly build and validate every component and every subsystem that goes into a subsea geothermal power plant.

As we scale from our first hundred‑kilowatt subsea demonstration to gigawatt deployments, the size and complexity of our test and production infrastructure will rise exponentially, rivaling the complexity of the power plants themselves. We believe an internal software team building the right stack from scratch is one of the highest‑leverage moves we can make as we scale. Every improvement you make increases the speed at which mechanical, electrical, firmware, and controls engineers can design, test, iterate, and deploy hardware.

Your job is to build the software ecosystem that enables that acceleration.

This role can span the entire software and hardware stack. You will work directly with electrical, mechanical, and test engineers to understand what they are building, identify how it should be tested, and rapidly create the infrastructure needed to answer critical engineering questions.

One day you will be writing bare‑metal and Linux firmware interfacing with custom PCBs, large‑scale industrial equipment, and next‑gen Endurance power plants. The next you will be closely embedding with engineers to build data acquisition and visualization systems that allow engineers to understand and control plants in real time, and the first generation of Endurance’s unified testing platform. Beyond that you will be building a high‑performance simulation stack to simulate our power plants and developing hardware‑in‑the‑loop environments to test real operating conditions and failure modes.

As we scale, you will own the software stack to automate large‑scale production lines for Endurance’s power plants, with the goal of a lights‑out fully‑automated factory.

The ideal candidate is an exceptional software engineer who enjoys working up and down the stack, from firmware to web UIs. You should be equally comfortable designing foundational software architecture, writing software for non-technical users, and debugging software with hardware in the loop. You be a part of Endurance’s software team and support firmware/full stack/controls projects across the company.

You will be the first software engineer focused on test and automation infrastructure at the company. You will work directly with the founding team and engineering leadership across Endurance, and as the function grows, you will have significant influence on the company’s software architecture, engineering standards, and future hires.

• Design and build the software ecosystem that powers testing across Endurance, from component qualification through full integrated system validation.

• Architect and implement hardware‑in‑the‑loop (HITL) and simulation environments that allow firmware and controls software to be tested under realistic operating…