01 Software Engineer Fullstack London, UK →

Throxy; Greater London; Hybrid; GBP 70,000 - 120,000; Full time

Job summary

throxy is building an ambitious AI-powered dialing and data platform in London. We’re seeking experienced fullstack engineers to own end-to-end systems, including frontend and backend work with TS/React (Next.js). A CS degree or equivalent and UK-based relocation with visa sponsorship are required.

Join a small, senior team shipping core infrastructure that drives revenue for Fortune 500s and startups alike, with real user impact and rapid iteration.

Qualifications

• Professional software engineering experience: 3+ years for mid-level, 6+ years for senior roles
• Fullstack web development: frontend and backend
• Strong CS fundamentals: data structures, algorithms, performance trade-offs
• TypeScript and React experience; Next.js is a big plus
• A CS degree or equivalent from a strong university
• Based in the UK or willing to relocate to London; visa sponsorship available for you and your spouse

Responsibilities

• Own problems end-to-end; design and ship end-to-end systems
• Build and maintain real-time infrastructure and data pipelines
• Develop the data engine, intelligence layer, and related tooling
• Collaborate in a small team to ship features that drive revenue
• Iterate rapidly with real users to improve performance and reliability

Skills

Fullstack development

TypeScript

React

Next.js

AI/LLM experience

Education

CS degree or equivalent

Tools

Next.js

React

TypeScript

Job description

Most applied AI companies sell tools. throxy sells the work itself: pipeline that closes revenue. Our customers don't care how it happens. They care that it does. That distinction changes everything about the engineering. Every improvement we ship makes the service faster and harder to compete with. Better models don't threaten us. They compound us.

We have product-market fit, month-over-month growth, and a clear roadmap. Small, senior engineering team where your code directly drives revenue. This is a rare window: early enough to build foundational systems, our customers range from Fortune 500s to the fastest-growing startups.

North Star

Own problems end-to-end. You'll build the systems you've seen at other companies, from scratch, with real users from day one. Scope it, build it, ship it, iterate.

Why throxy

01 The model compounds you

Every AI improvement makes our service faster and harder to compete with. You're building on a tailwind, not racing against one.

02 Proven, not speculative

Product-market fit, month-over-month growth, and customers paying for outcomes. The business works. Now we need to scale the engineering.

03 Build what you've only seen

Dialer infrastructure, agent systems, intelligence pipelines. The systems you've watched other companies build, you'll own here.

04 Small team, real leverage

A handful of AI-augmented engineers shipping systems that generate pipeline for dozens of customers, Fortune 500s among them. Your work has outsized impact because the team is small and the surface area is large.

The stack:

We're building with TypeScript, React, Next.js, and Bun. Our infrastructure runs on AWS: Postgres, ClickHouse, OpenSearch, and Datadog, with an Elixir core under the dialer. We care about clean code, fast iteration, and engineering excellence.

What You'll Build

01 Maestro, Our In-House Dialer

Real-time calling infrastructure on an Elixir core, placing millions of calls a month, with inbound, callbacks, and voicemail detection on local models.

02 The Data Engine

Provider waterfalls, LLM qualification and evaluation pipelines, a self-healing lead dataset, and scoring that decides who gets called next.

03 The Intelligence Layer

Post-call insights and call-outcome classification, fed back into the next campaign.

04 Beyond Off-The-Shelf

Every tool we've outgrown gets rebuilt as our own.

Strong signals

01 Top-Tier Experience

Experience at a high-calibre tech company: FAANG, Bloomberg, Stripe, Shopify, Revolut, Datadog, or similar.

02 Startup DNA

Time at a startup or small team (< 20 people) where you wore many hats.

03 AI/LLM Builder

Experience building with AI/LLMs: AI agents, RAG systems, or LLM-powered features.

04 Ships Solo

You've built something end-to-end on your own: a side project, an open source tool, a past business.

Must-Haves

What we're looking for:

01 Professional software engineering experience: 3+ years for mid-level, 6+ years for senior roles

02 Fullstack web development skills: comfortable building in both the frontend and backend

03 Strong fundamentals in computer science: data structures, algorithms, performance trade-offs

04 TypeScript and React experience (Next.js is a big plus)

05 A CS degree or equivalent from a strong university

06 Based in the UK or willing to relocate to London (we sponsor visas, including your spouse)

Hiring Process

Our hiring process:

Screening call

We get to know each other. We'll talk about your experience, what you're looking for, and give you a clear picture of throxy.

Technical phase

A hands-on assessment of your coding and problem-solving skills.

Follow-up conversation

Meet more of the team, talk about culture, role expectations, and comp.

We aim to move through the full process in 72 hours.