Kamrul Hassan
Archive / 001 Recovered 2026 · 23.81° N · 90.41° E

Kamrul Hassan: The story of a Software Engineer

Kamrul Hassan

Software Engineer · Builder · Learner

I build software, systems and ideas that turn complexity into something useful.

Begin reading Write to me
01 — Origin

The person behind the script

Portrait of Kamrul Hassan in a dark suit and tie
Plate 0 the author — Dhaka

I am a software engineer in Dhaka, and for more than seven years I have been building the systems organisations quietly run on — enterprise ERPs for retail, manufacturing, pharmaceutical, hospital and metal businesses, and one-stop service platforms that process permits for the Government of Bangladesh.

Most of that work is written in PHP — Laravel and Yii — with React on the front, MySQL and SQL Server underneath, and Python wherever automation or machine learning is involved. At Multibrand Infotech I lead a seven-person web and mobile team, which mostly means designing architecture and databases I will have to live with, reviewing code, and helping other engineers make better decisions than I did.

I build for the conditions that actually exist here: bandwidth that is expensive and unreliable, power that cuts out, shopkeepers who think in Bangla and get paid through bKash. Designing around those constraints — and automating away the repetitive parts of a client’s day — has taught me more than any framework has.

02 — Chronicles

Chronicles

A record of the years, kept the way archives keep them: dated, numbered, and without embellishment.

  1. May 2023 — Present Entry 04

    Senior Software Engineer

    Multibrand Infotech Ltd · Dhaka

    Leading a seven-member team across web and mobile development — owning architecture, database design and code quality from requirements to delivery.

    1. Record 01

      Analyse requirements and design software architecture; own database design and performance.

    2. Record 02

      Run code reviews, resolve the hardest technical issues and mentor the team.

    3. Record 03

      Use AI agents (Claude) and Python automation to speed up development, review and delivery.

  2. Oct 2020 — Apr 2023 Entry 03

    Programmer

    Multibrand Infotech Ltd · Dhaka

    Three and a half years of building — web applications taken all the way from system study to production.

    1. Record 01

      Developed web applications end to end, from requirement analysis to deployment.

    2. Record 02

      Wrote clean, optimised code in close collaboration with cross-functional teams.

    3. Record 03

      Adopted new technologies continuously and brought them into production projects.

  3. May 2019 — Oct 2020 Entry 02

    Junior Software Developer

    Business Automation Limited · Dhaka

    Where the professional record begins: modules built to specification, bugs owned, and the slow accumulation of judgement.

    1. Record 01

      Built and maintained software modules to specification.

    2. Record 02

      Took ownership of code quality and bug fixes.

    3. Record 03

      Tested new software and worked alongside senior developers.

  4. 2013 — 2017 Entry 01

    B.Sc. in Computer Science & Telecommunication Engineering

    Noakhali Science and Technology University

    The groundwork: algorithms, systems and networks — and the habit of learning things properly.

03 — Craft

Technical inventory

Tools, catalogued by drawer — not scored. Each entry carries a short note on how it is actually used.

Drawer I Languages 05 items

  • My daily language — every ERP and government platform in this record runs on it.
  • Interfaces. Vanilla where it is enough, React where it earns its weight.
  • Automation, scripting, and computer-vision pipelines at the edge.
  • Where I spend disproportionate time. Schemas outlive every framework.
  • Semantic markup and design systems kept in tokens.

Drawer II Frameworks 06 items

  • Modular monoliths, multi-tenancy, queues — and test suites in the hundreds.
  • Enterprise ERPs: maintained, extended, and carefully migrated.
  • Dashboards and ERP front ends that stay fast as they grow.
  • Content sites and product front ends that need server rendering.
  • Design systems in tokens rather than in anyone’s memory.
  • Admin and back-office interfaces that ship quickly.

Drawer III Databases 04 items

  • The default. Partitioning, covering indexes, reading query plans.
  • For enterprise and government clients already on Microsoft.
  • When the problem wants richer types and stricter constraints.
  • Document storage where the data genuinely has no fixed shape.

Drawer IV Cloud & DevOps 04 items

  • EC2, RDS and S3 — right-sized rather than over-provisioned.
  • Deployments I configure, harden and keep alive myself.
  • Every recent project runs in containers, locally and in production.
  • Message queues between services that must not lose work.

Drawer V Observability 03 items

  • Dashboards that tell you something is wrong before a client does.
  • Metrics scraped, stored and alerted on.
  • Logs you can actually search at two in the morning.

Drawer VI AI & Automation 04 items

  • Part of the daily workflow — development, code review and delivery.
  • Scripts that remove the repetitive parts of a team’s — or a client’s — day.
  • Digitising handwritten ledgers, writing summaries, voice entry in Bangla.
  • Detection and tracking on CCTV streams, on hardware that stays on site.

Drawer VII Workflow 04 items

  • Branching models, reviews and CI that a whole team can follow.
  • Planning and tracking larger client engagements.
  • Day-to-day delivery for a web and mobile team.
  • Issue tracking on long-running government and ERP projects.
04 — Works

Works of record

Client systems built at work, then products built independently. Figures come from the record itself — the CV, or the project’s own documentation and test suite. Nothing is rounded up.

THENPLATFORMEACH COMPANYyii 1.190 tablesmoduleby moduleCONSOLElaunch a companyschema blueprintmigrate allco. Aco. Bco. CworkflowpurchasesalesstockaccountsreportsONE KEYBOARD-FIRST WORKSPACEstock report68s → 0.4seach company, its own databasePLATE IGEN. ARRANGEMENTK.H. 2026
Plate I Invexa — general arrangement
Project 0012026 · Trading & inventory · multi-tenant SaaS

Trading and inventory software for parts businesses — purchasing to collections, every company on its own database, shaped to how it actually works.

Problem
A trading business was running on a 90-table Yii 1.1 system that could not be switched off — and every trading company works differently: some stock goods on save, others against orders; some deliver on the spot, others against challans.
Solution
Rebuilt on Laravel 12 module by module over the live schema — purchasing, sales, inventory, accounts — with every ledger verified against the old system. Then turned into SaaS: each company on its own database, its workflow chosen at launch.
Technology
LaravelMySQLMulti-tenancy
Impact
0.4sstock report, was 68s85business tables5modules
Commissioned work 03 artifacts
  • Project 002

    Enterprise ERP Systems

    Retail · manufacturing · pharma · hospital · metal

    Custom ERP platforms covering HRM, inventory, accounting, CRM, procurement, manufacturing, POS and BI reporting.

    PHP · Laravel · Yii · React · MySQL · SQL Server

  • Project 003

    Government One-Stop Service

    BEZA & BIDA — Government of Bangladesh

    Permit and licence processing for international investors, centralised in one place: project clearance, import/export, work permits, visas.

    PHP · MySQL · Workflow

  • Project 004

    Wheelhouse

    Fleet & workshop operations · 500+ vehicles

    One platform for a fleet’s whole life on the road and in the workshop — tracking, fuel, drivers and pools, then servicing, parts and invoices.

    PHP · Laravel · MySQL

Independent products 08 artifacts
  • Project 0052026

    Pawfolio

    Pet-care SaaS · clinics, groomers, boarding

    Everything a pet needs, organised — health records, appointments, invoices and reminders for vets, groomers, sitters, daycare and pet shops.

    Laravel 12 · Livewire 3 · Tailwind 4 · MySQL · Redis

  • Project 0062026

    Ledgerline

    Double-entry accounting

    Double-entry accounting with an insert-only general ledger, multi-company books and complete financial reporting.

    Laravel · MySQL · Bootstrap

  • Project 0072026

    Muster

    HR, attendance & payroll

    A complete HR office — from the fingerprint at the gate to the salary sheet — with biometric sync, leave approvals, payroll and an employee app.

    Laravel 11 · MySQL · Sanctum API · ZKTeco · DomPDF

  • Project 0082026

    Baki Khata

    SaaS · PWA · Android · AI

    The shopkeeper’s paper credit notebook, rebuilt for the phone — dues, payments, WhatsApp reminders and online collection.

    Laravel · Alpine.js · Flutter · bKash · AI

  • Project 0092026

    AgencyOS

    Multi-tenant SaaS

    Operations for manpower and service agencies — from worker and requirement through matching, assignment, invoicing and payment.

    Laravel 12 · Livewire · MySQL · Redis

  • Project 0102026

    F-Commerce Orders

    Multi-tenant SaaS

    Order management for sellers on Facebook, Messenger, WhatsApp and Instagram — orders, customers, payments and invoices.

    Laravel · MySQL · Multi-tenancy

  • Project 0112026

    Cheque Writer

    Business software

    Prints onto genuine bank cheque leaves with millimetre precision — template designer, printer calibration, registers and reports.

    Laravel · MySQL · DomPDF · Chart.js

  • Project 012In development
    ON PREMISESCLOUDboundarycam 01cam 02cam 03EDGE NODEdetectonnxtrackbytetrackspoolofflinevideo stays hereevents · signedCONTROL PLANEmoduleslaravelrulesescalationaudithash-chainwebappbandwidth: costlyanywherePLATE IGEN. ARRANGEMENTK.H. 2026

    Sentinel AI

    AI platform · SaaS + edge

    Edge-first AI CCTV intelligence. Detection runs on site; video never leaves the premises — only events do.

    Laravel · React · Python · FastAPI · ONNX · Flutter

Engineer’s field notes

Sketches of the ideas that keep recurring across these systems — drawn the way I explain them on a whiteboard.

Plate II The ledger that cannot be edited Posted vouchers are never changed — only reversed. Every balance can be rebuilt from history.
Plate III One database per company A platform console provisions each workspace from a blueprint; nothing is shared but the code.
Plate IV Designing for the connection you have Entries queue on the device and replay with idempotency keys — a retry can never post twice.
Plate V The road to production Nothing ships that has not passed the suite; containers make every environment the same one.
05 — Notes

Notes from the field

  1. i.

    Complexity should serve people, not impress them.

  2. ii.

    Good software disappears into usefulness.

  3. iii.

    Build slowly. Understand deeply.

  4. iv.

    Design for the connection you have, not the one you wish for.

06 — Next chapter

The next chapter

Every story eventually needs another page.

Let’s build something useful.

Email
kamrulofficial24@gmail.com
LinkedIn
kamrul-dev-guy (opens in a new tab)
GitHub
kamrul1717 (opens in a new tab)
Location
Dhaka, Bangladesh
Write to me
Archive / 001

Contents

kamrulofficial24@gmail.com
Dossier · Project 001

2026 · Trading & inventory · multi-tenant SaaS

Invexa

One product, configured per company — each on its own database.

Type
Multi-tenant SaaS
Isolation
Database per workspace
Stock report
68s → 0.4s

Problem

Trading companies do not all work the same way. Some stock goods the moment a purchase is saved, others receive against orders; some deliver on the spot, others against challans. The product had to fit each real workflow without forking the code for every customer.

Migration

The original system — Yii 1.1 over 90 tables — kept running while it was rebuilt on Laravel 12 one module at a time: master data, purchasing, sales, inventory, then accounts. Every write path was reverse-engineered and every ledger, stock value and profit figure verified to the taka against the live database. The stock report, rewritten to aggregate before it joins, went from 68 seconds to 0.4.

Approach

Every workspace gets its own database, provisioned from a schema blueprint and migrated by the platform, with connections and cache isolated per workspace. Store locations, purchase receiving, sales delivery and product identification are chosen at launch; the interface, stock movements and reports follow those settings.

Result

A keyboard-first workspace for purchasing, stock, sales and accounts, a reports centre across every module, and a platform console that launches new companies.

Technology Laravel · MySQL · Multi-tenancy
Dossier · Project 002

Retail · manufacturing · pharma · hospital · metal

Enterprise ERP Systems

One system for the whole business — built for five very different industries.

Industries
Retail, manufacturing, pharma, hospital, metal
Modules
8 core domains + BI
Result
Up to 35% efficiency gain

Scope

Custom ERP platforms for clients in retail, manufacturing, pharmaceuticals, hospitals and the metal industry — HRM, inventory, financial accounting, CRM, procurement, manufacturing, point of sale and business-intelligence reporting.

Build

PHP on Laravel and Yii, React front ends, and MySQL or Microsoft SQL Server depending on what the client already ran.

Result

Client operational efficiency improved by up to 35% through process automation and fewer manual errors.

Technology PHP · Laravel · Yii · React · MySQL · SQL Server
Dossier · Project 003

BEZA & BIDA — Government of Bangladesh

Government One-Stop Service

Many offices, one window — for investors coming into Bangladesh.

Clients
BEZA · BIDA
Also
NHA · Land Ministry
Users
International investors

Scope

Modules for Project Clearance, Import/Export Permits, Work Permits and Visa Recommendation on the one-stop service platforms of the Bangladesh Economic Zones Authority and the Bangladesh Investment Development Authority — centralising permit and licence processing for international investors.

Also

Contributed to the National Housing Authority’s flat allotment system and the Land Ministry’s e-Mutation project.

Technology PHP · MySQL · Workflow
Dossier · Project 004

Fleet & workshop operations · 500+ vehicles

Wheelhouse

From the road to the service bay — every vehicle, trip, part and invoice in one record.

Fleet
500+ vehicles
Vehicles
Traditional & electric
Modules
11

On the road

A fleet operations platform supporting more than 500 vehicles. I designed the modules for vehicle tracking, maintenance scheduling, fuel-usage analysis, driver scheduling, pool management and the reporting dashboards on top.

In the workshop

Servicing operations for traditional and electric vehicles: service scheduling, parts inventory, invoicing, customer management and a complete service history for every vehicle.

Technology PHP · Laravel · MySQL
Dossier · Project 005

2026 · Pet-care SaaS · clinics, groomers, boarding

Pawfolio

One codebase, shaped per workspace — a vet clinic, a groomer and a boarding kennel each see their own product.

Type
Multi-tenant SaaS
Languages
English & Bangla
Automated tests
740 · 4,630 assertions

Problem

Pet businesses run on paper cards, phone calls and memory: vaccinations go overdue, appointments collide, and invoices are written by hand. Clinics, groomers and boarding kennels need different tools, but none of them wants to run three systems.

Approach

A multi-tenant platform shaped by business type, with six independent tenancy enforcement layers and a test suite whose whole job is trying to break them. Clinical records with vaccinations and per-dose medication schedules, a drag-to-move calendar with a public booking page, server-computed invoices, and reminders that are generated idempotently and sent exactly once.

Result

Eight phases shipped — from health records to a platform console with audited impersonation — in English and Bangla, light and dark, keyboard-navigable, with 740 tests, PHPStan level 6 and PSR-12 clean.

Technology Laravel 12 · Livewire 3 · Tailwind 4 · MySQL · Redis
Dossier · Project 006

2026 · Double-entry accounting

Ledgerline

Every transaction through vouchers, into a ledger that cannot be edited.

Type
Accounting software
Voucher types
11
Automated tests
263 · 927 assertions

Problem

Accounting software earns trust by being impossible to quietly change. The books had to stay consistent across companies, branches and periods, and every figure had to be traceable to its source.

Approach

Vouchers move from draft to approved to posted; posted entries are never edited, only reversed. Month locks and year-end close protect finished periods. Receivables and payables carry FIFO ageing and enforced credit limits, with budgets, fixed-asset depreciation and an audit trail on every model.

Result

General ledger, trial balance, balance sheet, profit and loss, cash, bank, day and journal books — all exportable — backed by 263 automated tests.

Technology Laravel · MySQL · Bootstrap
Dossier · Project 007

2026 · HR, attendance & payroll

Muster

The muster roll, rebuilt: who came in, who is on leave, and what everyone is paid.

Type
HR & payroll platform
Domain model
55+ entities
Clients
Web + employee mobile API

Problem

Attendance lives on a fingerprint device, leave lives on paper, and payroll lives in a spreadsheet that someone rebuilds every month. Getting from a punch at the gate to a correct salary sheet was manual, slow and hard to audit.

Approach

Punches sync automatically from ZKTeco biometric devices, with location-checked attendance for staff in the field. Shifts, working days, holidays, late and early-out rules turn raw punches into attendance; leave moves through configurable multi-layer approvals. Payroll builds salary sheets from salary structures, tax slabs, provident fund, loans, advances and bonuses.

Result

One system for the whole employee lifecycle — hiring records, increments, promotions and transfers, assets and inventory, notices — with role-based permissions, Excel and PDF exports, bulk imports, database backups, and a Sanctum API that powers an employee app for attendance, leave and notices.

Technology Laravel 11 · MySQL · Sanctum API · ZKTeco · DomPDF
Dossier · Project 008

2026 · SaaS · PWA · Android · AI

Baki Khata

The shop’s paper khata, rebuilt for the phone in every shopkeeper’s pocket.

Type
SaaS · PWA · Android
Language
Bangla-first, English
Automated tests
141

Problem

Small shops in Bangladesh run on credit — baki — tracked in paper notebooks. Balances drift, reminders are awkward to send, and connectivity in many markets comes and goes.

Approach

Phone-number sign-in and a given/received ledger with a stored running balance and full audit log. Entries made offline queue on the device and sync with duplicate-safe retries. Customers get a signed link to view their own ledger and pay through bKash or SSLCommerz. Premium plans add an AI khata-photo digitiser with human review and Bangla voice entry.

Result

A web app, installable PWA and Flutter Android app on one API, with 141 tests covering tenant isolation, ledger arithmetic, payment webhooks and offline-sync deduplication.

Technology Laravel · Alpine.js · Flutter · bKash · AI
Dossier · Project 009

2026 · Multi-tenant SaaS

AgencyOS

A manpower agency’s whole day, from requirement to worker payment.

Type
Multi-tenant SaaS
Tenancy
Fail-closed scoping
Automated tests
376

Problem

Manpower agencies juggle workers, client requirements, placements, invoices and payouts across spreadsheets and phone calls, with money moving through manual bKash and Nagad transfers.

Approach

One flow — worker, requirement, matching, assignment, invoice, payment, worker payment — with tenant scoping that fails closed: without a tenant context, queries refuse to run rather than leak. Contracts, attendance, alerts, reports and exports sit on top.

Result

Subscriptions, a platform admin console and a command-palette search across the agency — with 376 tests, including isolation tests that post real Livewire requests across tenants.

Technology Laravel 12 · Livewire · MySQL · Redis
Dossier · Project 010

2026 · Multi-tenant SaaS

F-Commerce Orders

Everything a social-commerce seller needs to run orders — and nothing they don’t.

Type
Multi-tenant SaaS
Payments
Manual bKash verification
Automated tests
250+

Problem

Many sellers run their business from chat threads and notebooks. They need order tracking, not an ERP.

Approach

A deliberately narrow scope — no payroll, accounting or warehouse modules. Payments are honest about being manual: the customer sends bKash, the seller verifies it in their own account and marks it verified; the app never claims otherwise.

Result

Orders, customers, payments, invoices and WhatsApp messaging in one place, with owner, manager and staff roles and an automated suite that includes tenant-isolation tests.

Technology Laravel · MySQL · Multi-tenancy
Dossier · Project 011

2026 · Business software

Cheque Writer

Millimetre-accurate printing on real cheque leaves.

Type
Business software
Precision
Millimetre positioning
Exports
PDF · Excel · CSV

Problem

Every bank’s cheque layout differs, and every printer feeds paper slightly differently. Writing cheques by hand is slow and error-prone; printing has to land exactly on the lines.

Approach

A drag-and-drop template designer with millimetre coordinates, grid overlay and per-field typography, plus printer calibration with offsets, scaling and a printable test grid. It only fills genuine leaves issued by the bank — it never generates cheques or imitates security features.

Result

Cheque history, a running-balance register, post-dated tracking, bank and payee management and role-based permissions — exportable to Excel, PDF and CSV.

Technology Laravel · MySQL · DomPDF · Chart.js
Dossier · Project 012

2026 · AI platform · SaaS + edge

In development

Sentinel AI

AI CCTV intelligence where video never leaves the building.

Type
AI platform (SaaS + edge)
Clients
Web, edge node, mobile
Automated tests
838 backend · 109 edge

Problem

Expensive and unreliable bandwidth, frequent power interruptions, 8–64 cameras per site, and customers who will not accept a monthly bill measured in terabytes. The architecture had to start from the opposite assumption to the usual one.

Approach

A Python edge node runs detection with a shared ONNX backbone and ByteTrack tracking, assembles events and spools them offline when the link drops. It pairs with the cloud by claim code and talks over an HMAC-signed API. The control plane covers sites and zones, an encrypted camera registry, recording timelines with gap detection, alert escalation ladders and a JSON rule engine with dry-run replay.

Result

Twenty modules — from TOTP authentication and a hash-chained audit trail to visitor passes that verify offline, licence-plate recognition that never opens a barrier unattended, and face recognition that is off by default behind a consent ledger. 838 backend and 109 edge tests run without a model, GPU, camera or network.

Technology Laravel · React · Python · FastAPI · ONNX · Flutter