Staff / Senior Software Engineer

United Kingdom Source: WhatJobs

£90,000–£130,000

We’re a fast growing AI startup on a mission to help midmarket businesses transform how work gets done.

We’ve built a factory for custom operations agents. The factory builds Virtual Agents: software workers with AI reasoning that complete complex workflows end-to-end, directly in customer tools. There’s no tech integration, process change or upfront cost. Onboarding is white-glove, takes a matter of days, and customers pay only for delivered value.

This makes Virtual Agents the lowest risk way to automate complex manual work. And it makes Unitary the first company delivering Fortune 500-grade AI deployment with the unit economics of software - enabling us to reach the midmarket at scale.

Today we’re focused on commercial insurance, marketplaces and primary healthcare. But the potential for Virtual Agents goes far beyond.

We closed $15M Series A funding in 2024, and we’re backed by some leading names in AI (Plural and Creandum). We’re working with world-class clients such as Substack, Trustpilot, Depop, Sony Interactive Entertainment, and many more.

This is an exciting opportunity to join a well-funded startup at a crucial stage of growth, and to play a significant part in turning frontier AI technology into real world value.

The role

As a Senior Software Engineer you will:

Bring new products to market

We’ve been able to grow our revenues aggressively by combining a service and product offering to our customers. We now want to productise this offering as much as we can. We will need to bring new products to market, you will be at the forefront of this.

Re-imagine and refactor our existing services and tooling into a new generation of capabilities

Our current toolset has helped us grow from 0 to 25 clients in the past 18 months. We are now finding that these services and tools will not scale far beyond this point in their current form. We need them to be re-imagined, in light of our learnings from our pathfinder clients, into robust capabilities that can match the growth of our business.

Bridge our Machine Learning, Product and Platform Engineering capabilities

We have an extremely talented pool of full-stack machine learning and MLOps engineers and an exceptional platform engineering team. We need software 'glue' expertise and capability to bring these two things together optimally. With our other software engineers, you will be this glue.

The role will report to a Staff Engineer and can be based in the UK or alternatively anywhere within 3 hours of the UK timezone.

As part of this role, you will:

Work closely with our operations engineering lead and customer success team to establish priorities across multiple customers and ensure operational excellence.
Triage and resolve technical issues raised by customers and internal teams.
Lead or contribute to post-mortems when contractual service level agreement breaches occur, identifying root causes and driving preventive improvements.
Operate the AI decision engine to make targeted improvements to automation accuracy.
Update customer workflows when requirements change, working with the customer success team to assess scope and confirm delivery timelines with the customer.
Contribute to internal tooling and automation that will drive efficiency during the day-to-day service operations.
Write and maintain runbooks and documentation that enable our internal agent operations teams to become more self-sufficient over time.
Participate in our 24/7 on-call rotation.

You

We are looking for someone who is excited about building innovative solutions and wants to have a large impact in a smaller company; you will be a key part of defining Unitary’s future during this early stage of our next growth journey. We need versatile people who are happy to get stuck into whatever needs doing, and are ready to learn and grow with the company.

For this particular role, we need a product-focused software engineer with deep technical expertise who takes ownership of problems from start to finish. You will be comfortable working across the stack and across disciplines, equally at home shaping a brand-new product and untangling and rebuilding existing systems. Communication is crucial, as you will work closely with colleagues across machine learning, product, and platform engineering to bring their work together into capabilities the whole team can build on.

We would love to hear from you if you:

Have expert Python development experience and write production-grade code
Have experience bringing products to market - ideally taking a product from 0 to 1, or productising a service offering
Have experience re-imagining and refactoring systems and tooling so they scale reliably as a business grows
Use AI coding agents as a core part of how you work, with hands-on experience of agentic tools (e.g. Claude Code, Codex)
Are an advocate of strong software engineering practices, standards, and culture
Are still building hands‑on and want to keep doing so for at least the next 12 months

It would be even better, but not essential, if you have:

Previous experience working in a startup or small team
Are confident using AWS and Kubernetes
Experience with workflow orchestration systems (e.g. Temporal)
Can venture into Data Engineering, MLOps and/or Platform Engineering

About us

Unitary is a remote‑first team of 25+ people spread across Europe who are fiercely passionate about making the internet a better place, and deeply motivated to become a force for good. We have an ambition to create a company filled with happy, kind and collaborative people who achieve extraordinary things together. Our culture is built around the power of trust, transparency and self‑leadership.

Working at Unitary

We are committed to creating a positive and inclusive culture built on genuine interest for each other's well‑being. We offer progressive and market‑leading benefits, including: