Senior Software Engineer

Online Filings

Senior Software Engineer developing next-generation web applications and APIs. Leading technical design and mentoring junior developers at Online Filings, a company empowering entrepreneurs.

Posted 7/27/2026full-timeLondon • 🇬🇧 United KingdomSenior💰 £50,000 - £65,000 per yearWebsite

Core Competencies

Role fit

Core Competencies

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Demonstrates expertise in leading the design and development of scalable web applications and APIs, with a strong focus on application security, performance optimization, and team mentorship. Proficient in utilizing modern technologies such as TypeScript, ReactJS, and SQL to deliver high-quality solutions aligned with business goals.

Highest-signal resume keywords

NodeJS Application DevelopmentRESTful API DesignSQL Data ModelingTeam LeadershipApplication Security Best Practices

ATS Keywords

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Applicant Tracking System Keywords

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Hard Skills

TypeScriptReactJSNext.JSNodeJSSQLPostgreSQLAPI DevelopmentPerformance OptimizationScalable ArchitectureAutomated Testing

Soft Skills

Excellent CommunicationOrganizational SkillsProactive Problem SolvingTeam CollaborationMentorship

Tools & Technologies

AWSStripeZendeskTwilioGoogle AnalyticsGoogle AdsCI/CD Processes

Industry Keywords

Web Application DevelopmentSoftware Development LifecycleCross-Functional CollaborationTechnical DesignDevelopment Best Practices

Tech Stack

Tools & technologies

AWSJavaScriptNext.jsNode.jsPostgresReactSQLTypeScript

About the role

Key responsibilities & impact

Lead the technical design and development of scalable, secure web applications and APIs, driving best practices across the development lifecycle.
Oversee system architecture decisions, ensuring alignment with business goals and scalability requirements.
Mentor and guide junior developers, fostering a collaborative learning environment.
Design and build RESTful API endpoints using NodeJS and Express, including detailed API documentation.
Design, optimize, and maintain complex SQL data models, ensuring efficient data structures, query performance, and reliability.
Develop responsive and performant front-end applications using ReactJS, focusing on UX/UI best practices.
Architect and maintain integrations with external APIs such as AWS, Stripe, Zendesk, Twilio, Google Analytics, Google Ads, HMRC, etc…
Enforce code quality through rigorous reviews, automated testing, and CI/CD processes.
Collaborate with cross-functional teams to gather requirements, set timelines, and deliver high-quality solutions on schedule.
Stay ahead of industry trends, introducing innovative tools and technologies to enhance development efficiency.

Requirements

What you’ll need

Education: Bachelor’s in Computer Science or related field from a Tier 1 university.
Experience: Minimum of 4 years of full-time professional experience in software development, with strong expertise in TypeScript, ReactJS, and Next.JS.
Solid experience in building RESTful APIs.
Proven track record of leading development teams and managing large-scale projects.
In-depth experience with PostgreSQL/SQL, including design of complex schemas, writing queries and performance optimisation.
Deep understanding of application security best practices, performance tuning, and scalable architecture.
Ability to troubleshoot complex technical issues, with a proactive and solution-oriented mindset.
Excellent communication, organisational skills, and the ability to work independently or within a team.

Benefits

Comp & perks

Competitive Salary: £50,000 - £65,000 per year, with potential performance-based increases.
Performance Bonus: Up to 10% annual bonus.
Generous Holiday Allowance: 27 days holiday plus bank holidays.
Health Insurance: Private health insurance including dental care, vision, and health screenings.
Lifestyle Benefits : benefit from up to 50% discounts at selected gyms and exclusive lifestyle accessory offers and rewards to support your physical health and well-being.
Mental Health Support : access to up to 8 free Cognitive Behavioural Therapy (CBT) sessions and free annual subscriptions to mindfulness apps like Headspace.
Retirement : We contribute 3% to your pension, for every 5% you contribute.
Powerful computer to work from your home.
Cycle to work scheme.
Flexible Working Options : hybrid setting (3 days in the office)