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COMPANY OVERVIEW Lydian is developing the lowest cost sustainable fuels from waste CO2, water, and renewable electricity to decarbonize the aviation industry. Our breakthrough technology replaces oil and gas refining with fully electrified, modular, and flexible reactor systems that produce fuel with 95% lower emissions than traditional jet fuel. Since our founding in 2021, Lydian has achieved key milestones in record time, including the production of our first liquid fuel from our pilot system, capable of producing ~10,000 gallons of fuel per year for a fraction of the capital and time of alternative approaches. Lydian is backed by top climate investors including Congruent Ventures, Galvanize Climate Solutions, Union Square Ventures, Voyager Ventures, Grok Ventures, and Overture. We are building a motivated, diverse, and collaborative team that is passionate about addressing the growing climate crisis and is committed to excellence in their work. In particular, we look for tenacious people who are energized by solving the hardest, highest impact problems that come their way. POSITION OVERVIEW Lydian is looking for a Senior Reactor Modeling Engineer to conduct multi-physics modeling/simulation and data analysis. You will develop thermofluid models of Lydian’s reactors and apply to them to various design, optimization, and experimental troubleshooting challenges. You will collaborate with experimentalists to gather data to validate your models, and will work with teams across the company as a lead for data handling and advanced data analysis. We are looking for someone with strong fundamentals in heat transfer, fluid mechanics, thermodynamics, and chemical reaction kinetics who can confidently synthesize multi-physics models. Our ideal candidate can reliably assess a physical system and then craft CFD and/or analytical models that accurately capture its behavior. You need to have a strong background in data analysis and experience providing data and model-driven insights to designers and experimentalists. RESPONSIBILITIES - Develop thermofluid/reaction models of Lydian’s custom-designed reactors - Perform detailed analyses (hand calculations, FEA, CFD, etc.) to support design and optimization of critical reactor components - Leverage models to sharpen our understanding of experimental systems, aiding with troubleshooting, design of experiments, and selection of process parameters - Collaborate with teammates to design, build, and execute tests to obtain experimental data for model validation and parameter extraction - Develop data analysis methods to support teams across Lydian - Collaborate with process engineers to implement parametrized reactor models in plant-level simulations QUALIFICATIONS - BS, MS, or Ph.D. in Mechanical Engineering, Chemical Engineering, or similar. MS or Ph.D. are preferred - 5+ years of experience in analysis of thermal fluid, reactor, or catalytic systems - Experience using CFD software (Ansys, COMSOL, OpenFOAM, STAR-CCM+, etc.) to analyze physical systems and guide product design - Skilled at analyzing experimental data, drawing meaningful conclusions, and presenting findings to a broader team - Strong ability to apply engineering principles—including thermodynamics, fluid mechanics, and heat and mass transport—to systematically approach complex design problems - Experience modeling reactors and chemical kinetics - Comfortable working independently to define and execute projects COMPANY CULTURE AND BENEFITS - Challenging, collaborative, and meaningful work and an important voice in company development - Competitive salary commensurate with experience - Meaningful equity compensation - Unlimited PTO and expectation that all employees take significant time off to rest, recharge, and enjoy life outside work - Excellent insurance with 100% of healthcare, vision, and dental premiums covered for the employee, and 80% coverage for dependents - 401(k) with company match

Listed by Lydian for a position based in the United States. Employers on this board attest they are hiring domestically.

Engineering

4 days ago

Senior Software Engineer (Remote)

Gynger · New York City, NY

Pay

$175k–215k

Setting

Remote

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Gynger is the agentic credit risk function for tech CFOs - unlocking embedded financing at the speed and scale of tech.

We're a cash flow management platform with embedded financing that gives B2B technology vendors the power to offer flexible payment terms to customers while securing upfront payment. Finance leaders use Gynger to combine actionable insights with capital, optimizing day to day cash flow, accelerating deal cycles, mitigating risk, and executing on long term strategy.

We're building the rails that financed tech B2B deals will run on. Our AI agents sit inside the credit and risk function, embedded directly in the sale, giving buyers buy-now-pay-later flexibility on their technology purchases while vendors get paid upfront.

Founded in 2021 and headquartered in NYC, Gynger has raised $20M in Series A funding with investment from Gradient Ventures, Velvet Sea, BAG Ventures, MXV Capital and others.

For the third year running, Gynger has been recognized as one of Built In's Best Places to Work 2026.

The Role

We're building the AI-native infrastructure for tech financing, and we're looking for a Senior Software Engineer who builds with AI, not just around it.

You'll help architect and develop the agentic systems that run our credit risk function — underwriting, risk monitoring, collections, and payments — as complete processes an agent can carry from start to finish, rather than a single feature layered on top of a workflow. You'll work across the stack, with particular depth on the backend: scalable APIs, thoughtful data architecture, and services built to support real financial workflows. You'll also help shape how we build, bringing modern AI-assisted development practices into our everyday work and helping our engineering standards evolve alongside the tools themselves.

This is a role for someone who wants a hand in shaping the product, the architecture, and the way the team works, not just executing what's already been decided.

Listed by Gynger for a position based in the United States. Employers on this board attest they are hiring domestically.

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