for Agencies and Companies That Need Delivery Capacity
I help software agencies deliver complex client projects by integrating seamlessly into existing engineering teams. From frontend architecture and React & Next.js development to performance optimization, architecture decisions, code reviews and mentoring, I help teams ship production-ready software without the overhead of hiring full-time.
Experienced engineering capacity when your team needs it
Your team has won new work, deadlines are approaching, or engineering capacity is stretched. I integrate into your existing workflow quickly and contribute like part of the team—without the overhead of hiring another full-time engineer.
Ideal for:
Own a feature from planning to production
Need an experienced engineer to take ownership of a feature, unblock a sprint, or deliver a complex feature without constant supervision? I integrate into your existing team and ship production-ready software with clear communication and predictable delivery.
Ideal for:
Code, architecture, and performance reviews
Get an experienced second opinion before committing to a migration or major release. I'll review architecture, performance, maintainability and Core Web Vitals, then provide practical recommendations—not a rewrite pitch.
Ideal for:
Scalable frontend architecture
From design systems and data-heavy dashboards to GraphQL, WebSockets and real-time applications, I build frontend architectures that remain maintainable as products grow.
Ideal for:
Internal tools & workflow automation
Build internal dashboards, admin panels, Chrome extensions and workflow tools that reduce manual work and help engineering teams move faster.
Ideal for:
Independent engineering support for teams shipping production software.
I work directly with software agencies and product companies that need experienced engineering capacity. No lengthy recruitment or onboarding—just an experienced engineer who integrates into your team and starts delivering.
Discuss your project
Production systems at Web3, DeFi, and enterprise insurance scale.
Multi-tenant frontend platform supporting 10+ Tryg subsidiaries.
Poland-based, EMEA hours — sprint and overflow delivery.
HoudiniSwap (MV3 extension, GraphQL real-time, multi-chain wallets), Unizen (landing redesign, React Native, monorepo), Tryg/TCS (enterprise multi-tenant frontend for 10+ subsidiaries). I've built and maintained production systems operating at scale.
I don't optimize for code alone. I optimize for maintainability, delivery speed, long-term ownership and business impact.
I take ownership of architecture, technical decisions and code quality, so your team can stay focused on delivering value. Faster delivery without compromising production quality.
You work with me directly — no PM relay, no agency markup layer. Remote B2B across EMEA, used to slotting into existing teams and tooling.
Web3 · Senior Frontend
Build security-sensitive frontend features for a fast-moving Web3 product with real-time blockchain interactions.
Developed production React features, GraphQL real-time integrations, MV3 browser extension functionality and multi-chain wallet experiences within an existing engineering team.
DeFi · Frontend
Support a product team delivering both web and mobile experiences from a shared codebase.
Redesigned the corporate website and contributed to a React Native application within a shared monorepo supporting both web and mobile.
Enterprise Insurance
Deliver and maintain a shared frontend platform supporting multiple insurance subsidiaries.
Developed production features within a multi-tenant frontend architecture used across more than ten enterprise deployments.
AI Assistant
Help developers identify potentially malicious code before integrating third-party repositories.
Built an AI-assisted developer tool using Next.js and the OpenAI API to analyse repositories and surface potential security risks before code integration.
Web3 · Senior Frontend
Build security-sensitive frontend features for a fast-moving Web3 product with real-time blockchain interactions.
Developed production React features, GraphQL real-time integrations, MV3 browser extension functionality and multi-chain wallet experiences within an existing engineering team.
DeFi · Frontend
Support a product team delivering both web and mobile experiences from a shared codebase.
Redesigned the corporate website and contributed to a React Native application within a shared monorepo supporting both web and mobile.
Enterprise Insurance
Deliver and maintain a shared frontend platform supporting multiple insurance subsidiaries.
Developed production features within a multi-tenant frontend architecture used across more than ten enterprise deployments.
AI Assistant
Help developers identify potentially malicious code before integrating third-party repositories.
Built an AI-assisted developer tool using Next.js and the OpenAI API to analyse repositories and surface potential security risks before code integration.
Web3 · Senior Frontend
Build security-sensitive frontend features for a fast-moving Web3 product with real-time blockchain interactions.
Developed production React features, GraphQL real-time integrations, MV3 browser extension functionality and multi-chain wallet experiences within an existing engineering team.
DeFi · Frontend
Support a product team delivering both web and mobile experiences from a shared codebase.
Redesigned the corporate website and contributed to a React Native application within a shared monorepo supporting both web and mobile.
Enterprise Insurance
Deliver and maintain a shared frontend platform supporting multiple insurance subsidiaries.
Developed production features within a multi-tenant frontend architecture used across more than ten enterprise deployments.
AI Assistant
Help developers identify potentially malicious code before integrating third-party repositories.
Built an AI-assisted developer tool using Next.js and the OpenAI API to analyse repositories and surface potential security risks before code integration.
15 minutes to confirm fit — your stack, timeline, and whether you need overflow, a scoped sprint, or an architecture review.
I work in your repo, your rituals, your hours window. Regular demos, PRs, and async updates — same as an embedded senior engineer.
Clear deliverables, timeline, and B2B contract terms. No equity, no cofounder framing — contractor capacity with defined outcomes.
15 minutes to confirm fit — your stack, timeline, and whether you need overflow, a scoped sprint, or an architecture review.
Clear deliverables, timeline, and B2B contract terms. No equity, no cofounder framing — contractor capacity with defined outcomes.
I work in your repo, your rituals, your hours window. Regular demos, PRs, and async updates — same as an embedded senior engineer.
Public recommendations and feedback from managers, colleagues and product teams I've worked with throughout my career.
Sergio was a perfect addition to our team. He has a keen eye for detail and evolved tremendously over time. I'd be happy to recommend him and would gl…
Martin Granström
CEO
Unizen
I had the pleasure of working with Sergio at HoudiniSwap, and I can confidently say he's both a strong engineer and a great teammate. He brings solid…
Halil Atila
Senior Frontend Lead
HoudiniSwap
Sergio is deeply passionate about his work and is a fantastic collaborator. When working with him, you can always rely on his support, being highly de…
Ganesh Singh
Frontend Engineer
Tryg
Sergio was a perfect addition to our team. He has a keen eye for detail and evolved tremendously over time. I'd be happy to recommend him and would gl…
Martin Granström
CEO
Unizen
I had the pleasure of working with Sergio at HoudiniSwap, and I can confidently say he's both a strong engineer and a great teammate. He brings solid…
Halil Atila
Senior Frontend Lead
HoudiniSwap
Sergio is deeply passionate about his work and is a fantastic collaborator. When working with him, you can always rely on his support, being highly de…
Ganesh Singh
Frontend Engineer
Tryg
Sergio was a perfect addition to our team. He has a keen eye for detail and evolved tremendously over time. I'd be happy to recommend him and would gl…
Martin Granström
CEO
Unizen
I had the pleasure of working with Sergio at HoudiniSwap, and I can confidently say he's both a strong engineer and a great teammate. He brings solid…
Halil Atila
Senior Frontend Lead
HoudiniSwap
Sergio is deeply passionate about his work and is a fantastic collaborator. When working with him, you can always rely on his support, being highly de…
Ganesh Singh
Frontend Engineer
Tryg
Bring in an experienced software engineer who can integrate quickly, take ownership, and deliver production-ready software alongside your existing team.