Complex workflows that earn trust.
Multi-tenant SaaS, fintech operations, trading platforms and internal systems where permissions, integrations and auditability shape the architecture.
International software engineering company
Software engineering for complex products and business-critical systems.
Sellbyx designs, builds, scales and modernizes B2B and B2C software for international clients. Our team works across product engineering, fintech and trading, real-time systems, cloud and data platforms, and applied AI.
End-to-enddiscovery through production
Senior-leddirect access to engineering leadership
B2B + B2Cproduct experience
Internationalremote delivery
01 / Product range
One engineering standard. Two very different product realities.
Consumer products built for growth.
Web, mobile and real-time products where responsiveness, traffic peaks, conversion and unit economics determine whether growth is sustainable.
02 / Engineering services
Complex product engineering, end to end.
Six focused service lines spanning product, software, data, infrastructure, quality and technical leadership.
Build · 01
Digital product engineering
Discovery, UX, web, mobile, backend and quality engineering carried through to dependable production delivery.
Build · 02Fintech & trading systems
Payments, financial workflows, market data and trading infrastructure designed for correctness, auditability and real-time operation.
Build · 03Applied AI & voice
Voice runtimes, agents, search and intelligent workflows engineered around measurable product value, latency and reliability.
Scale · 04Scalable backend & real-time systems
Distributed backends, APIs and streaming services built for high throughput, low latency, backpressure and graceful failure.
Scale · 05Cloud, data & platform engineering
Infrastructure, databases, search and delivery systems engineered for scale, observability, reliability and controlled cost.
Recover · 06Modernization & technical recovery
Independent technical leadership for systems constrained by scale, reliability, technical debt, architecture or delivery risk.
03 / Selected work
Selected systems and delivery decisions.
These case studies represent work delivered by the Sellbyx team. Client identities remain confidential where required, and metric limitations are stated within each case.
Trading · Client delivery
Scaling market-data delivery toward 500,000 concurrent connections
The Sellbyx team reduced per-connection overhead and redesigned real-time topic fan-out so each market update could be encoded once and shared across subscribers.
500Kproject target connections10–50reported updates/s per connection
Read engineering study Fintech · Client deliveryModernizing a regulated fintech platform without stopping delivery
The Sellbyx team delivered a staged architecture and infrastructure modernization program for a live financial product with complex integrations, operational risk and an active roadmap.
Phasedmigration pathLiveoperations maintained
Read engineering study AI · Product R&DEngineering a real-time voice runtime around the latency budget
A Sellbyx R&D program exploring streaming speech, contextual synthesis and model orchestration as one controllable real-time system.
Streamingpartial input and outputInstrumentedlatency by pipeline stage
Read engineering study 04 / Delivery model
A senior-led team owns the work from architecture through release.
Sellbyx keeps technical decisions close to implementation. The core team retains product context and accountability, while specialists join when the system needs deeper expertise.
05 / Business & technology blog
Practical answers for consequential software decisions.
Guidance for leaders connecting product growth, operating risk and engineering choices.
View all articlesEditorial queue
The first business guides are being prepared.
Browse the planned topics or bring Sellbyx a product question now.
Explore the blogDirect access to the delivery team