d4b — software studio
d4b is an independent software studio based in Poland. We build platforms, products, ecommerce systems, mobile applications, and AI integrations end to end for B2B product teams. Founded and led by Janusz Maciejewski, a platform engineer with over a decade of experience shipping software that outlasts the people who built it.
Services
- Fullstack product development — web applications, APIs, backends, dashboards. We own the full stack from database to pixel.
- Ecommerce — headless Magento, custom ecommerce platforms, storefronts, infrastructure, and third-party integrations (ERP, payments, shipping, marketplaces).
- Mobile — native and cross-platform mobile applications, backend services, and release pipelines.
- AI integrations — LLM features, agents, retrieval-augmented generation, and automation wired into real products with honest guarantees.
- Platform engineering — internal developer platforms, GitOps workflows, deployment automation, and platform teams.
- Kubernetes and infrastructure — cloud, on-premise, and hybrid Kubernetes clusters with Talos, ArgoCD, Kyverno, KubeVirt, Proxmox, Terraform, Helm, and Kustomize.
- Project management — discovery, scoping, delivery, and ongoing coordination kept on track without the theater.
- Fractional technical lead — senior hands-on engineering leadership for teams that need an outside read on architecture, hiring, or roadmap.
How we work
- Short intro call — 30 minutes, no pitch deck.
- Scoped engagement — fixed outcome, clear milestones.
- Ongoing partnership — retainer or fractional platform lead.
Engagement models: project, retainer, advisory. Typical start: 2 to 3 weeks from first email.
Who we work with
d4b partners with venture-backed startups, scaleups, and established product companies that need a reliable engineering partner to ship platforms, ecommerce systems, or AI features without the overhead of a large agency.
Contact
Email: janusz.maciejewski@gmail.com
LinkedIn: Janusz Maciejewski on LinkedIn
Website: d4b.online
Location: Poland (remote-first, working worldwide)