Backend Software Engineer

iO Associates; Greater London; Hybrid; GBP 65,000 - 90,000; Full time

Job summary

iO Associates is seeking a Backend Software Engineer in London for a hybrid role. You will design and implement distributed backend systems, storage, and platform primitives using Rust with Python at API boundaries, contributing to scalable data pipelines and services.

You will join a small, autonomous team at an early-stage company, shaping product direction, customer value, and engineering culture while balancing rapid delivery with robust, well-architected solutions.

Qualifications

• Minimum 2 years in industry.
• Experience designing and building backend services.
• Proficiency with Rust and Python in production environments.
• Experience with large-scale data infrastructure is a plus.

Responsibilities

• Design and build distributed systems, storage, and platform primitives.
• Work across the backend surface: APIs, data pipelines, and service architecture.
• Own architectural decisions to scale with petabyte-scale data storage.

Skills

Rust

Python

Distributed systems

AI-assisted development

System design

Collaboration

Tools

Kafka

PostgreSQL

TimescaleDB

PostGIS

gRPC

Protobuf

Kubernetes

Job description

Backend Software Engineer - London - Hybrid - Minimum 2 years in industry

Our clients culture is built on a foundation of radical candour and mutual trust. We recognise that being an industry leader requires more than just building exceptional products - it requires empowering a team of exceptional people. Individually, the team operates with high autonomy; collectively, they're unified by a shared drive to achieve their mission through a commitment to excellence.

The Role

We're looking for a Backend Engineer who pairs strong software skills with an ambitious, exploratory mindset. You're excited to join an early-stage company where you can have an outsized impact. The Backend team is a small yet critical part of a rapidly scaling company, so each member plays a role in shaping the product, its value to customers, and the culture as the company grows.

We're looking for someone who can design and build the distributed systems, storage infrastructure, and platform primitives that underpin the sensor integration product. You'll work across the full backend surface: from stream processing and storage, to API design, data pipelines, and service architecture, in a Rust stack with Python at the platform API boundaries.

You'll be responsible for building robust, well-abstracted systems that scale with the demands of a growing integration and customer base, with ambitions of petabyte-scale data storage. You'll own meaningful architectural decisions and be expected to reason clearly through unfamiliar problem domains under real constraints.

Core Skills

• Core technologies: Rust, with Python at some API boundaries. Kafka, PostgreSQL/TimescaleDB/PostGIS, gRPC/protobuf, and Kubernetes.

Candidates are not expected to have experience with all of these, but adjacent understanding is crucial.

• Systems thinking: Comfortable designing and operating production systems under real constraints - zero-downtime migrations, complex tradeoff analysis, and the kind of pragmatic decision-making that keeps services reliable as requirements shift.
• Software craft: Writes clean, well-structured code with good use of abstractions, namespaces, and interfaces. Opinionated about code review processes and culture.
• Reasoning under uncertainty: Can pick up unfamiliar systems and make sound architectural decisions without a complete picture.
• AI-assisted development: Fluent with LLM-assisted workflows and confident both steering AI tooling toward high-quality output and knowing which problems are better solved by humans.
• Collaboration: Experience or appetite for cross-team communication; comfortable seeking out context independently and building features with limited top-down instruction.
• Prior experience with large-scale data infrastructure, i.e. distributed storage, sharded databases, high-throughput pipelines. Bonus if you've built your own or have experience with the primitives for building your own, e.g. sharding libraries, consistent hashing, data-parallel dataflow computation, etc.