Senior Software Engineer (Python)

Location: Hybrid 2 days per week, based in Warsaw

Salary for Senior (IC3):

• UoP (Contract of Employment) = 23,000 - 31,000 PLN per month gross

• B2B = 27,000 - 37,000 PLN per month net +VAT

About hyperexponential (hx)

At hyperexponential, we’re building the AI-powered platform that enables the world’s most critical decisions in a $7 trillion industry, which risks to take, and how to price them. These are the decisions that shape real-world outcomes: whether rockets successfully launch into space, autonomous vehicles make it to market, or communities recover after major storms.

Until now, insurers have been making billion-dollar decisions using outdated tools. We’re changing that. Our platform brings together data, AI, and human expertise to give insurers the fastest path from submission to decision - helping them move faster, act smarter, and take on more risk with confidence.

Backed by a16z, Highland Europe, and Battery Ventures, we’re scaling globally - already trusted by nearly 50 of the world’s largest insurers, with zero churn and billions in premiums flowing through hx.

What began as a single product in one market has rapidly evolved into a multi-product, multi-territory platform powering every stage of pricing and underwriting. AI is at the core of what we do - from building the world’s first domain-specific AI peer programmer for insurance (think GitHub Copilot with a PhD in actuarial science) to shaping agentic workflows that reinvent how this industry operates.

What makes hx different is the people who build it. Here, impact isn’t tied to title or tenure; it’s defined by the challenges you take on and the discipline you bring. Surrounded by peers who stretch you, you’ll do the best, hardest work of your life in a company engineered to endure.

If that sounds like you, join us in building what comes next.

About the Models team

The Models team at hx is at the heart of our mission to empower customers with the tools to write, version, test, and visualise their models, directly impacting the core functionality of our platform. We are responsible for rearchitecting our technology stack to deliver features rapidly and securely, ensuring our services can handle increasingly complex and nested customer data.

Our team blends deep technical skill with a culture of collaboration, ownership, and open communication. We work closely across disciplines, tackling complex data and performance challenges that drive real customer value. Constructive challenge and transparent leadership are central to how we operate, with a focus on delivering reliable, scalable solutions.

As a Senior Backend Engineer, you will play a pivotal role in improving the scalability and reliability of the Models service, accelerating delivery through well-designed abstractions and strong software architecture decisions. You will also be a cultural force, leading by example in ownership, kindness, and proactive problem-solving.

Your Senior Engineer responsibilities

• Designing and implementing scalable backend solutions that enable the Models platform to handle increasingly complex and nested customer data, directly improving reliability and performance.

• Addressing technical debt and driving forward-looking architectural changes to support rapid growth and evolving customer needs.

• Building reusable components and abstractions that accelerate delivery across the group and empower other teams to move faster.

• Collaborating with cross-functional teams, including those working in Python, Rust and Kotlin, to deliver features that have measurable impact on customer experience and platform adoption.

• Leading by example in ownership, kindness, and proactive problem-solving, fostering a culture of continuous learning and high performance.

• Contributing to the rearchitecture of our core model code base, aligning with modern industry standards and preparing the platform for future challenges.

What you need to be successful

• Architected and delivered complex backend systems with proven experience leading technical initiatives in Python

  • Our teams use a combination of Python, Rust and Kotlin. Expect to be upskilled in Rust if you didn't already use it!

• Built and deployed cloud applications at scale, demonstrating the ability to deliver robust solutions in production environments.

  • We use AWS with ECS, EC2, Fargate, Lambda

• Designed and managed complex, arbitrary nested data structures tailored to diverse customer requirements.

• Demonstrated strong working knowledge of fundamental computer science and software engineering principles, including algorithms, data structures, complexity, design patterns, and architecture.

• Owned and delivered projects through the complete product development lifecycle, from conception to delivery.

• Collaborated effectively across teams, driving initiatives that improved scalability, reliability, or delivery speed.

Interview Process

1. Initial screening with Talent team to kick things off (30 minutes)

2. Manager Interview (60 minutes)

3. Technical Assessment: Bi-Directional Code Review (120 minutes)

4. Values Interview (60 minutes)

5. We offer!

How hx Warsaw Works

At hyperexponential, we believe in a balance between remote work, and building relationships across teams and locations. You’ll have your main office in Warsaw, 2 days a week, with also ability to travel to London HQ to meet the wider team. International travel will be much less frequent, perhaps 2-3 times a year.

Warsaw HQ was established in 2023, quickly hiring our first handful of high-calibre engineers. Fast-forward to today in 2025, there are 50+ in Warsaw and surrounding cities who travel for the collaborative environment.

On Wednesdays you’ll often find Warsaw HQ organising team lunch paid by hx, getting drinks after hours. The office is also dog-friendly, so feel free to bring yours along!

What Your Offer Could Look Like

B2B

• Share Options at a highly successful Series B company

• 25 days of non-working + Polish bank holidays

• £5,000 GBP budget for Learning & Development

• Mental Health Support and Therapy via Spectrum Life

• Optional for you: access to Private Healthcare via Luxmed + Multisport (fully funded by yourself as B2B Contractor)

• Top-spec laptop (MacOS or Windows)

Contract of Employment (UoP)

• Share Options at a highly successful Series B company

• £5,000 GBP budget for Learning & Development

• 26 days of holiday + Polish bank holidays

• Company pension

• Company Sick Pay for 10 days at 100% salary

• Mental Health Support and Therapy via Spectrum Life

• Monthly Wellbeing allowance via Juno

• Private Healthcare Insurance via Luxmed

• Multisport - Classic level

• Top-spec work equipment (MacOS, Windows + additional monitors, mechanical keyboards etc)