Work

Projects and products

Software we operate and client work we have delivered. Each entry documents scope, engineering approach, stack, and outcome.

Contact us →Case studies →

4

Projects delivered to production

9

Active engineering engagements

6

Engineering domains covered

100%

Client handover rate

Selected work

Project list Products and client delivery

Filter

Live uptime monitoring at echo.zolestio.com — scheduled checks, email alerts, and a public status page you can share with clients.

Read case study →

Multi-seller marketplace — 20 product categories, PayPal/PayHere checkout, seller subscriptions, commissions, and payouts. Pre-launch QA.

Read case study →

Offline-first shop register — shifts, mixed-tax checkout, 58/80 mm thermal receipts, and Z-Report. v1.0.0 on Linux, Windows, and macOS.

Read case study →

On-premise ERP — finance, sales, purchasing, inventory, CRM, and documents. LAN multi-user for up to five workstations. v1.0.0.

Read case study →

Fashion eCommerce storefront with PayHere checkout — deployed to production with documentation handover.

Read case study →

PayHere payment integrations for Zolo and client eCommerce projects — checkout flows, webhooks, and reconciliation patterns we have shipped to production.

View services →

Case studies

Challenge → architecture → results. How we build for production scale.

Echo · HTTP · TCP · Status page · Email alerts
Live productLive

Echo — uptime monitoring and public status pages

SaaS we build and run at echo.zolestio.com. Add monitors; Echo checks on a schedule, alerts on status changes, and publishes a shareable status page.

Challenge

Small teams and freelancers need to know when a client site or API is down — and want one link to share with customers instead of ad-hoc “is it down?” messages.

Approach

Web dashboard and API, plus a separate probe service. Results stored in PostgreSQL; alerts by email, Slack, and webhook.

What we built

  • 5 monitor types (HTTP, TCP, ICMP, heartbeat, Echo Connect)
  • Public status page, embed widget, badges, JSON API
  • Free and Pro tiers with PayHere billing · 14-day Pro trial
  • Maintenance windows · REST API for automation

Results

  • Live at echo.zolestio.com
  • Probe engine (Vitals) separated from web API for reliable scheduled checks
  • Notification delivery history and user preferences in-app

Stack: React · TypeScript · Vite · Python · FastAPI · PostgreSQL · Go (Vitals / LM / SE / NE) · Redis · Docker · Brevo · PayHere

View Echo product →Visit echo.zolestio.com →
Zolo · 20 categories · PayPal · PayHere · Seller payouts
Pre-launch productPre-launch QA

Zolo — multi-seller marketplace

Multi-seller marketplace across API, web portals, and a worker for billing and notifications. Customers shop many sellers; sellers run shops with subscriptions, commissions, and PayPal payouts.

Challenge

One checkout must split orders by shop, isolate seller inventory, calculate marketplace commission, and route payments and payouts correctly.

Approach

FastAPI backend and React portals for customer, seller, admin, and logistics. Background jobs handle trials, payment retries, commissions, and order email.

What we built

  • 20 product category forms · Guest and account cart/wishlist
  • Multi-shop checkout · PayPal + PayHere payments
  • Seller tier subscriptions · Seller dashboard and order fulfilment
  • Admin finances and moderation · Logistics order portal · Real-time notifications (SSE/WebSocket)

Results

  • Web app feature-complete in pre-launch QA
  • Staging at api-stg.thezolo.com · Production URLs configured (zolo.zolestio.com)
  • Launch target end of 2026

Stack: React · Python · FastAPI · PostgreSQL · Celery · Redis · Go (vitals-zolo) · Docker · Brevo · PayPal · PayHere

View Zolo product →
MiniBook3 · Offline-first · PyWebview · SQLite · v1.0.0
Live productLive

MiniBook3 — offline-first point-of-sale

Shop register for a single location. v1.0.0 is a desktop app on Linux, Windows, and macOS — no cloud account, no network required for checkout.

Challenge

Counter sales need to work when connectivity is unreliable. Installation must be simple for shop owners without developer tools. Currency and tax calculations must stay exact under load.

Approach

Desktop shell with a local Python API and SQLite. React checkout UI. Role permissions. Installers per platform with checksums.

What we built

  • Three-column checkout shell · 4 shop modes (Pharmacy, Boutique, Food, Misc)
  • Shifts with drawer variance · Mixed-tax checkout · Cash/card payment
  • Barcode keyboard-wedge / USB scan · Suspend/recall carts · Returns by receipt
  • Thermal 58 mm / 80 mm + PDF receipts · Cash drawer kick · Z-Report
  • Product catalog + CSV import · Daily backup · Up to 10 users

Results

  • v1.0.0 released 2026-06-30 · 470+ automated tests
  • Property-based cart fuzz (1,000 scenarios, zero rounding drift)
  • Installers on releases.zolestio.com/minibook3

Stack: React · TypeScript · Vite · Python · PyWebview · SQLite · PyInstaller

View MiniBook3 product →Download →
ZDeck3 · GL · Sales · Purchasing · LAN (5 users)
Live productLive

ZDeck3 — on-premise ERP

On-premise ERP for small business. v1.0.0 covers finance, sales, purchasing, inventory, CRM, documents, and reporting — up to five LAN users, no license key.

Challenge

Small businesses need integrated operations and accounting without cloud dependency or per-seat licensing complexity. Multiple staff must work concurrently without corrupting shared records.

Approach

Python desktop app with role-based UI. SQLite with LAN access and record locking. Optional C++ help for large reports.

What we built

  • General ledger + financial statements · Quote-to-cash sales · Procure-to-pay with three-way match
  • Inventory with FIFO/weighted average · Banking reconciliation · Quick-sale POS · Payroll lite
  • CRM deals/tasks · OCR document import with review step · Ad-hoc report builder
  • Backup/restore · CSV/Excel import · EN/SI locale packs · LAN multi-user (5 workstations)

Results

  • v1.0.0 released 2026-06-24 · 116+ automated tests including LAN concurrency and role matrix
  • Installers on releases.zolestio.com/zdeck3

Stack: Python · PyWebview · SQLite · DDD · Tesseract OCR · PyInstaller · C++ (optional native reports)

View ZDeck3 product →Download →
Monday · Fashion catalog · PayHere · GCP
Client deliveryDelivered

Monday — fashion eCommerce (client)

Fashion eCommerce for a regional client — React storefront, FastAPI API, PayHere checkout, GCP deploy, and documentation handover.

Challenge

Launch a mobile-friendly catalog and checkout with local payment integration, without over-engineering for day-one traffic.

Approach

React storefront and FastAPI API with PostgreSQL. PayHere checkout with webhooks. Deployed on GCP with separate staging and production.

What we built

  • Product catalog and cart · PayHere checkout · Order admin
  • Responsive layout · Deployment pipeline · Operator documentation

Results

  • Deployed to production · Cross-device QA complete
  • Documentation and handover session delivered · Post-launch support period completed

Stack: React · TypeScript · Vite · Python · FastAPI · PostgreSQL · GCP · PayHere

Contact us — similar eCommerce build →

Current numbers Delivered projects include documentation and handover

0
Projects delivered to production
0
Active engineering engagements
0
Years of focused experience
24/7
Engineering support availability

Start a project

Tell us what you need. An engineer reads every inquiry and replies within one business day.

Contact us →View services →

Download our software

MiniBook3 PoS and related installers with guided setup.

Browse downloads →

Back to home

Products, services, and how we work.

Go to home →