Full Stack Developer

We’re on a mission to set a bold new standard for mobile. It started with Classic SIM, our essential everyday SIM that includes bills that drop, support in seconds, and a shrinking carbon footprint. Thousands of happy customers joined us. But we knew people still faced two big problems: rubbish signal and expensive roaming. So we built Smart SIM, our game‑changing back‑up eSIM giving you unbeatable signal and free global roaming. Now we’re proud to have more than 63,000 customers on our journey. We’re also the UK’s first B Corp mobile network, a carbon‑negative company and member of 1% for the Planet.

We’re looking for a talented and curious Full Stack Developer to help take our product to the next level. In this role, you’ll help shape the technical direction of our product, looking beyond the standard stack to introduce new technologies, techniques, and ideas. You’ll play a key role in the full development lifecycle, delivering high‑quality features and continuously improving how our backend and frontend platforms are built.

You’ll work across our API, databases, network and infrastructure, internal tools (including team and customer‑facing dashboards) and web‑based interfaces, creating experiences that truly delight our users. Reporting to the Head of Engineering, you’ll be a core part of our small but mighty tech team, collaborating closely with developers and product to make a meaningful impact across the full stack.

Our engineering team is at an exciting stage of growth as we explore how AI can accelerate development, level up our coding, enable fast adoption of new languages and frameworks, to help us achieve our ambitious goals.

• Design, build, and maintain scalable backend services and APIs using TypeScript and Python
• Develop performant, intuitive frontend features for internal and customer‑facing tools
• Work with Postgres to design efficient schemas and write clean, optimised SQL
• Contribute to infrastructure and DevOps – from CI/CD pipelines to monitoring and alerting
• Help set up and maintain networking and firewall rules with tools like iptables, tc, Suricata, RADIUS
• Deploy and manage services on Google Cloud Platform, using its managed tools and infrastructure
• Collaborate in code reviews and architecture discussions to maintain high engineering standards
• Troubleshoot and resolve production issues across the full stack
• Work cross‑functionally with product, customer operations, and marketing to deliver seamless user experiences
• Help shape engineering best practices and build internal tools to support our team

You’re a strong generalist with experience across both frontend and backend. You’re fluent in modern TypeScript but you’re language‑agnostic and enjoy quickly learning new languages and technologies. You’re comfortable with infrastructure, DevOps, networking and cloud deployment (bonus: GCP experience). You’re skilled with relational databases (Postgres) and writing efficient SQL, and ideally have worked with NoSQL and other database types too. You’re pragmatic, curious, and motivated by solving real user problems. You’re comfortable owning projects end‑to‑end in fast‑moving environments. You’re committed to clean, maintainable and well‑documented code. You’re a clear communicator, who collaborates well and isn’t afraid to challenge assumptions and is happy asking questions or challenging assumptions. You’re excited by AI and its potential to accelerate development and assist with fast iteration and experimentation.

What you’ll get in return for all your hard work:

• Ownership in Honest through our EMI option scheme
• 25 days of annual leave, plus all bank holidays
• Your birthday off each year on us!
• A hybrid‑first working environment with at least 1 day per week in the London office
• An Honest sim, and refurb phone on us
• 1 paid volunteering day each year
• Wellbeing budget through Heka
• Cycle to Work scheme
• £500 annual learning budget

Why join Honest?

• Backed by top investors including Sidebyside, DMGV, WAYRA, Ascension and TinyVC
• Being part of a talented team that likes to have fun
• Fast‑learning, entrepreneurial environment where we focus on supporting your growth and personal development
• Opportunity to help shape the future of Honest
• We’ll provide you with all the tools and technology you need to do your best work
• Working for one of the UK’s top rated mobile networks on Trustpilot
• Make your mark at the UK’s most ethically rated and highest scoring B Corp mobile network

Diversity, inclusion, equity and belonging at Honest: Here at Honest, we’re all about doing the right thing, even especially when no one’s looking. That includes building an inclusive environment where everyone feels like they belong and proud to be their true selves every day. We’re committed to providing the support our team needs to thrive and do their best work. We believe it’s our differences that make us stronger and celebrate diversity in the Honest team. Learning from one another’s unique experiences, perspectives and ideas is how we win. That’s why we strongly encourage applications from all walks of life.