CASE 06 · SAAS
A full-scale cloud B2B product of team-sized scope: 120,000+ lines of code, 10 microservices, 400+ API endpoints, integrations with three marketplaces and three banks, payment processing, realtime updates and multi-user access with roles.
THE CHALLENGE
Marketplace sellers live in scattered data: WB and Ozon dashboards, bank statements, cost-price spreadsheets, expense lists in Excel. Pulling it together by hand is slow and error-prone, and money leaks go unnoticed.
The goal was to build a service that collects every data source automatically, consolidates it into management reporting and stays fast on large volumes — while being developed and operated by a single engineer.
ABOUT THE PRODUCT
Legko i Prosto (“Easy & Simple”) is a management accounting service for marketplace sellers and small businesses. It pulls data from every part of the business — Wildberries, Ozon, Yandex Market, bank accounts, offline sales — into unified reporting and gives the owner an accurate net profit calculation in 30 minutes.
Dashboards for orders, sales, stock, buyout rate and geography; a week-over-week report that shows not just margin dynamics but the reasons behind the changes; per-product analytics with ABC analysis.
Cash flow and P&L reports (liquidity, expense structure and margins), a payment calendar, loan and liability tracking, breakdowns by legal entity, business line and expense category.
Bank statements sync on their own, and a configurable rules engine classifies transactions and allocates expenses across products and stores. Hours of manual Excel work now happen without human involvement.
WHAT WAS BUILT
THE PROJECT IN NUMBERS
ENGINEERING DECISIONS
All heavy financial and analytical math lives in MySQL stored procedures. Reports over hundreds of thousands of transactions build fast, and the logic is reused by every service — API, workers and dashboards.
Scheduled managers hand out sync jobs to horizontally scalable workers over an internal API. Loading data for hundreds of stores never slows down the main application.
Process clustering and auto-restart, memory limits, automatic SSL certificate renewal, versioned builds, separate dev/test/prod environments.
JWT authentication with SMS sign-in, permission checks on every endpoint, OAuth bank connections with no client credentials stored.
STACK
The product's only developer. Full cycle: architecture and database design, backend and frontend, bank and marketplace integrations, billing, infrastructure, deployment and production support.
SEE ALSO
Cash flow, P&L and per-product unit economics, LLM-to-SQL, deployed inside the client perimeter.
Event sourcing, carried interest calculation, document generation. 76,000+ lines of TypeScript.
Service pages with scope and pricing are available in Russian.
CONTACT
I'll design and build the same kind of product around your processes — from architecture to operations. Get in touch and we'll scope the task, timeline and budget.
Message on Telegram dnovoselov@bk.ruI reply within 3 hours on weekdays
A project's budget and commercial terms belong to the client, and I don't publish them. Your project will be treated the same way. My own price ranges are in the Pricing section.