Hello!
Sebastian Töllke
Cloud Architect, Platform + Software Engineer
Kind Software Engineer, Cloud Architect, and Staff Platform Engineer with 11+ years of experience across monolithic, distributed, and cloud-native systems.
Whether you're looking to build using on-prem hardware, remote infrastructure, or AWS and Cloudflare primitives: I can help you or your company make it happen with care and attention to detail.
Building fast, secure, cost-effective, and smooth user experiences is extremely satisfying to me. The same goes for consulting on architecture, CI/CD flows, technology choices, and cost-conscious systems that people can actually run.
My background is in electrical engineering and design. Nowadays I spend my time exploring web tech, building tools, mentoring engineers, and learning as much as I can!
I trained a model on my life in Google Vertex and all I got was this lousy summary: "Seb likes making music, woodworking for his tuxedo cat, cooking spicy food, exploring the world, charity work, restoring cameras, tabletop RPGs, and finding rare YouTube videos."_
Professional Experience
Cloud Architect at JustFab Ltd.
Jun '24 – May '26- Designed multi-brand AWS/Cloudflare architecture for high-traffic commerce systems across JustFab, FabKids, and ShoeDazzle, improving availability, scalability, and operational simplicity.
- Built an edge-native inventory backend and API on Cloudflare Workers, KV, Durable Objects, D1, and R2, keeping essential services resilient with predictable operating cost.
- Re-platformed a key B2B API with Terraform and GitHub Actions, cutting delivery lead time 60% and reducing p95 latency from 6.5s to under 900ms.
- Productionized blue-green and multi-stage CI/CD for Cloudflare Worker APIs consumed by brand sites and a custom navigation tool, improving release safety for critical paths.
- Introduced agentic AI-assisted workflows for PR review, incident triage, testing, and migration analysis, enabling 8 engineers and human-in-the-middle coverage work reaching 20%+ across a large multi-brand codebase.
- Led a provider-consolidation roadmap forecast to shrink service footprint 24% by simplifying architecture, improving ownership, and retiring legacy services.
Staff Software Engineer at JustFab Ltd.
Nov '23 – Aug '24- Consolidated fragmented APIs into clearer service boundaries, achieving 94% faster responses and steadier operating costs.
- Helped deliver a high-pressure frontend stack migration, removing legacy code while reducing service partner costs and improving developer experience.
- Planned, built, and operated a global B2B partner API on AWS using Lambda orchestration, on-prem SQL Server, Cognito OAuth, and Kinesis to Graylog streams, now serving international production traffic.
Engineering Team Lead at JustFab Ltd.
Apr '22 – Nov '23- Managed a 5-engineer fully remote team serving JustFab, FabKids, and ShoeDazzle, lifting overall system stability by 18% and doubling cache hit rates.
- Introduced Sentry and Graylog error-replay workflows, improving incident response and reducing mean time to detect production issues.
- Integrated Builder.io into the legacy stack, unlocking content self-service for 26+ business users, and built a production-ready translation-plugin MVP using fast LLM inference for EU language workflows.
Senior Software Engineer at JustFab Ltd.
Apr '20 – Apr '22- Led the Foundation team, creating cloud-native microservices that cut API latency 30-40% and enabled rapid A/B roll-outs across JustFab, ShoeDazzle, FabKids & Fabletics Ltd.
- Drove the business-critical shift to fully remote development across North-American units.
Senior Software Engineer at TechStyle Fashion Group
Apr '18 – Apr '20- Helped form the Foundation team, improving site performance, checkout success, and retention with edge-first and microservice patterns.
- Embedded React/Next.js into the monolith, modernizing DX and CX.
Web Developer at JustFab GmbH
Sep '14 – Apr '18- Built the first mobile storefront for all EU markets (jQuery, ColdFusion, image optimization).
- Created an email-templating engine that cut turnaround time 40% and increased deliverability.
- Led a US-EU code-autonomy program, shrinking release cycles.
Technical Expertise
Over the years of my professional career I've worked with many different services, systems, languages, frameworks, and libraries. While this list is not comprehensive it should give you a half-decent overview of the technologies that I am comfortable with.
- JavaScript (TS)
- Golang
- Bash
- Python
- PHP
- SQL
- React
- Next.js
- Remix
- Astro
- Vue
- Nuxt
- SolidJS
- Svelte
- Redux
- Jotai
- Zustand
- Styled Components
- Tailwind CSS
- SASS/SCSS
- Vitest
- Jest
- Puppeteer
- Vite
- Webpack
- Turbopack
- Turborepo
- Nx
- Hono
- Bun
- ElysiaJS
- NestJS
- Express
- FastAPI
- AWS
- Cloudflare
- Vercel
- Fly.io (flyctl)
- Netlify
- Docker
- Kubernetes
- SST
- Terraform
- GitHub Actions
- Figma
Engineering Practice
Tools are only part of the picture. The work I enjoy also sits in the space between architecture, delivery, reliability, and the practical workflows that help teams build better systems with less friction. This is not just keyword-farming, I swear!
- LLM Assisted Development
- Agentic Workflows
- Code Review Automation
- Internal Tooling
- Knowledge Retrieval
- Human-in-the-Middle Flows (HITM)
- Distributed Systems
- API Design
- Observability
- Event-Driven Design
- Incident Response
- Performance Optimization
- Cost Optimization
- Systems Consolidation
- Progressive Delivery