004
UI engineering, real-time systems, full-stack product work, and enterprise fintech workflows.
Engineering Case Files
Souvik Sen
Product-focusedfull-stack engineer
Building fast React products, real-time SaaS workflows, and developer tooling.
A collection of engineering case files documenting product work, system design, performance improvements, and developer tooling.
Cmd + K / Ctrl + KMobile-first archive
At A Glance
004
Public tools spanning React packages, CLI utilities, and backend scaffolding.
CURRENT
Fintech and enterprise workflow work at Phlo Systems.
Featured Cases
Four documented investigations across interface systems, real-time architecture, product delivery, and enterprise trade-finance workflows.
Each case is framed as a solved engineering file: what the problem was, what had to be understood, how the approach was shaped, and what evidence supports the outcome.
04 active cases
UI engineering, real-time systems, full-stack product delivery, and regulated workflow surfaces.
Interface to workflow
The set spans frontend systems, delivery architecture, and user-facing product surfaces.
Problem to evidence
Each file follows the same documented structure instead of behaving like a gallery card.
Case Register
CASE 001
Active filePublished package
react-dragdrop-kit
Controlled drag-and-drop primitives for React: sortable lists and grids, plus a headless Kanban path, built on pragmatic-drag-and-drop and shipped as a tree-shakeable npm package with a live demo.
Outcome
A reusable layer for reorder and board moves where application code owns IDs, positions, and persistence while the toolkit standardises drag mechanics and drop semantics.
Filed Under
UI Engineering / Open Source
Evidence
03 logged notes
References
03 external links
CASE 002
Documented systems build
NotifyFlux
Multi-tenant notification stack: Express and Socket.IO, MongoDB change streams, Redis-backed socket fan-out, JWT-scoped tenancy, and a React admin console for delivery visibility.
An end-to-end path from persisted events to tenant-scoped real-time delivery, with an operator-facing UI that shows activity instead of hiding it behind raw API calls.
Filed Under
Real-time Systems
Evidence
03 notes
CASE 003
Live product build
HaveItDiscussed
Developer community client: discussions, threaded comments, likes, profiles, social graph, notification hub, and dark mode—deployed to Netlify against a separate Node API (`HaveItDiscussed-Server`).
A shipped forum product where reading, posting, and notifications share consistent client patterns instead of each screen inventing its own data lifecycle.
Filed Under
Full-stack Product
Evidence
03 notes
CASE 004
In progress
Phlo Systems — trade-finance workflows
Frontend work on regulated trade-finance and operations surfaces: long-running cases, document-heavy steps, and dashboards where operators need current status without fighting the UI. Filed while the implementation is still evolving inside the organisation.
A documented line of work on enterprise workflow UX and live data—scoped honestly as in-flight, with public references limited to organisation context and role-level description.
Filed Under
Enterprise fintech / workflow UX
Evidence
03 notes
Evidence Log
Verified outcomes from performance, workflow, and delivery work.
A recorded set of measurable improvements across latency, state synchronization, delivery systems, and deployment workflow.
Primary Finding
90%
Reduction in redundant API traffic
Compared to the same navigation paths before deduplication—measured from browser network logs (duplicate GETs per route mount and refetch storms on parent re-renders). Achieved by consolidating data fetching behind shared hooks, normalised cache keys, and request coalescing so identical queries while a view is active resolve once.
Logged Findings
Evidence 02
35%
Improvement in page load times
Compared to the pre-split bundle for the same routes—using Lighthouse / browser performance traces on representative pages. Driven by route-level code splitting, deferring non-critical chunks, and trimming render work on first paint so interactive time moved without changing product scope.
Evidence 03
70%
Reduction in dashboard refresh latency
Compared to polling-based refresh intervals on operator dashboards—wall-clock time from server-side event to visible UI update in manual timing runs. Achieved by pushing deltas over SignalR (and analogous socket paths) so the client invalidates or patches targeted queries instead of waiting for the next poll cycle.
Evidence 04
80%
Reduction in manual deployment effort
Compared to the prior release checklist (build locally, upload artefacts, verify by hand)—tracked as steps per release in the old process versus GitHub Actions workflows that build, test, and deploy on merge with the same verification gates each time.
Field Notes
Field Notes
A progression from broad web work into systems, product, and frontend depth.
A concise timeline of how the work moved from implementation breadth into stronger product judgment, operational rigor, and frontend ownership.
FILE 01
Early broad web development
Built a broad foundation by moving quickly across the web stack and learning through practical implementation work.
FILE 02
Teaching and internship phase
Worked on full-stack delivery while also mentoring and explaining concepts, which strengthened engineering communication and fundamentals.
FILE 03
Systems and operations growth
Moved deeper into infrastructure, automation, CI/CD, and production-facing workflows where reliability and process mattered more.
FILE 04
SaaS product engineering
Focused more on user-facing products, internal tooling, and real-time workflows that required both implementation depth and product judgment.
FILE 05
Current fintech and open-source focus
Now working in fintech workflow software at Phlo Systems while continuing to publish developer tooling and technical writing.
Archive
A public archive of utilities, packages, and developer-facing tools.
A smaller set of published tools focused on reusable abstractions, workflow polish, and practical starting points.
Archive 01
react-dragdrop-kit
Reusable drag-and-drop toolkit for React lists, grids, and board-style interfaces.
Archive 02
git-time-travel
CLI utility for editing Git commit timestamps during history cleanup workflows.
Archive 03
noexgen
Express.js application generator with a production-ready project starting point.
Archive 04
@yourstruggle11/unslugify
Utility for converting URL slugs into readable labels without manual mapping.
Reports
Technical writing on internals, engineering ideas, and implementation tradeoffs.
Notes and explainers written to make the underlying thinking legible, not just the final API surface.
Featured Report
React 19 Reconciliation Deep Dive
A closer look at React internals and the engineering implications of reconciliation behavior.
Understanding React Reconciliation in React 18: A Deep Dive
React 18's enhanced reconciliation algorithm brings harmony between performance and user experience, propelling web development to new heights.
4 min read / Jun 3, 2023
Open Related ReportYour Google Maps Works Because of Einstein
A technical explainer that connects relativity to software systems people use every day.
Drag and Drop in React Doesn't Have to Be Painful
A practical breakdown of the problem space behind react-dragdrop-kit and why a cleaner approach helps.
Contact
Open to senior frontend and full-stack roles, product engineering work, and thoughtful collaboration.
Best fit conversations usually involve React systems, SaaS workflows, developer tooling, or frontend architecture that needs to hold up under real product pressure.
Current Status
Current context
Phlo Systems / trade-finance workflows
Location
Kolkata, India
Open to
Senior frontend, full-stack, and product engineering work
Preferred Threads
React systems and frontend architecture
Especially product surfaces where performance, structure, and maintainability matter together.
Real-time SaaS workflows and tooling
Useful when the work mixes interface quality with workflow depth, system clarity, and internal product tooling.
Roles, product work, and thoughtful collaboration
Strong conversations usually start with a concrete product, system, or developer-experience problem.
Channels
Index Status
Open for roles, product engineering work, and React-focused collaboration.
Email is the best direct route for opportunities. GitHub, LinkedIn, and Medium provide the surrounding project, writing, and open-source context.