Frontend Engineer III

Zilch; City of Westminster; On-site; GBP 85,000 - 110,000; Full time

Job summary

Zilch is seeking an FE Software Engineer IV to drive the mobile experience across iOS and Android using React Native. You will craft high‑quality code, lead technical design, and focus on performance, security, and reliability.

With 6+ years in software, you will champion best practices, collaborate with backend teams, and push for improvements in testing, deployment, and developer experience. London-based, on-site 3 days per week.

Qualifications

• 6+ years' overall experience in software development.
• 4+ years' experience with TypeScript and React.js.
• 4+ years' experience building React Native mobile apps (iOS/Android).

Responsibilities

• Lead design and refinement of mobile app features with performance goals.
• Develop rock-solid, secure, well-tested mobile components.
• Collaborate with API and back-end teams to ensure secure data handling.
• Improve build, test, and deployment processes for mobile apps.
• Support ad-hoc development and related duties as needed.

Skills

Typescript development

Reactjs

React Native

Mobile app development

iOS and Android native bridging

Tools

Appium

Maestro

PactFlow

Firebase

CodePush

Bitrise

ContentStack

Job description

Who we are: We're one of Europe's fastest-growing fintech companies - on a mission to create the world's most empowering way to pay. We launched the product in 2020 and achieved double unicorn status, valued at $2 billion, and since then have taken on more than 6 million customers. Our mission is to become the best way to pay for anything, anywhere and say goodbye to credit costs for everyone. This is huge.

About the role

We are on the lookout for an individual who is filled with energy, someone who radiates enthusiasm and a passion for software development. We are looking for an FE Software Engineer IV who puts their all into their work, crafting exceptional code. Our ideal candidate is not just interested in software but lives and breathes it, and consistently maintains the highest standards of quality.

Day‑to‑day responsibilities

• Working in an agile environment with multiple team members on user stories that deliver significant impact for our customers.
• Taking the lead in technically designing and refining improvements to our Mobile App, including performance improvements, memory optimisation, seamless animations and complex 3rd party integrations.
• Building mobile components that are rock-solid, secure, well-tested, and highly performant.
• Continually improving our code, our systems, our practices, and our knowledge utilising experience gained throughout your career.
• Working with our APIs and back-end components to ensure we store and process information securely and effectively.
• Improving our mobile developer experience internally and streamlining our app test and deployment processes.
• Assist in ad-hoc development and technology related duties.

What we’re looking for

• 6+ years' overall experience.
• 4+ years' experience typescript development.
• 4+ years' using Reactjs.
• 4+ years' developing iOS and Android react native apps.

Bonus skills

• Exposure to other mobile development systems & languages.
• Bridging React Native to Native code.
• Mobile testing frameworks including Appium and Maestro.
• Contract testing frameworks including PactFlow.
• App deployment technology including Firebase, Codepush and Bitrise.
• Exposure to Styled Components.
• Experience with AWS, AWS Lambda.
• Experience with Content Management Systems, especially ContentStack.

Location and working arrangement

Happy to work on-site in our London Victoria office 3 days per week.