Open to remote · Relocation with visa sponsorship

Md. Rakib Ahasan

Senior .NET Backend Engineer · Fintech & Payments

I build and scale fintech and enterprise platforms that handle millions of users.

Backend for 50M+ users · 99.9% uptime · API 110s → 9–13s

Contact me Download CV GitHub LinkedIn
Portrait of Md. Rakib Ahasan
01 / measurable impact

Numbers that survived production.

Performance work is only useful when the system, team, and customers feel the difference.

99.9%

Production uptime

50M+ users

500 GB+

Minimal-downtime migration

<2h cutover

~90%

API response-time cut

110s → 9–13s

70%

Less manual reporting

Automated pipelines

4h → 30m

Deployment cycle

Jenkins CI/CD

02 / request path

How I make it fast.

Trace the work from client request to useful response. Hover or tap a node for the optimization lens.

Clear contracts, predictable payloads, and fast feedback at the edge.

before / after
before · hot grid110s
after · tuned path9–13s
03 / operating history

Systems, not job titles.

The through-line is backend ownership: understand the constraint, measure the path, ship the smallest durable fix.

April 2026 — Present

JustGo Technologies Limited

Dhaka, Bangladesh (Hybrid) | Sports membership & club-management platform | .NET 9, SQL Server, Dapper

Software Engineer — Backend

  • →Owned backend delivery across Member Profile, Venue Management, Invoice Management, and Payment modules of a modular .NET platform, keeping API behavior consistent across modules for web and mobile clients.
  • →Integrated Adyen payment methods — ACH, BACS Direct Debit, SEPA Direct Debit, and PayTo — with cart/store-based merchant account and API-key resolution, enabling payments across the UK, US, Europe, and Australia.
  • →Reduced a high-traffic grid API from ~110s to 9–13s (~90% faster) through query-level tuning and caching.
  • →Resolved provider, currency, acquirer, refund-tax, and asynchronous payment-status defects across payment workflows, improving reliability of failed and pending transactions.
  • →Built audit logging and observability — profile-level change tracking, receipt-level logs, and provider-response analysis — speeding up troubleshooting and traceability.
  • →Implemented business-critical validation and workflow logic with xUnit tests for core scenarios, improving accuracy and regression resistance.
Jan 2025 — Mar 2026

DataSoft Systems Bangladesh Ltd. — Client: bKash

Dhaka, Bangladesh | Mission-critical .NET Core applications for 50M+ users

Software Engineer (promoted from Software Developer)

  • →Developed and maintained mission-critical .NET Core applications for bKash, sustaining 99.9% uptime in production for 50M+ users.
  • →Led a 500 GB+ SQL Server → MySQL migration with a <2-hour cutover window (minimal downtime), including full rollback and validation planning.
  • →Automated Excel/PDF reporting pipelines with ASP.NET Core and Jenkins CI/CD, cutting manual effort by 70% and deployment time from 4 hours to 30 minutes.
  • →Owned escalated production incidents through systematic root-cause analysis, eliminating recurring performance degradation during peak business hours.
  • →Designed RBAC for 500+ users, AES-256 encryption for sensitive data, and activity audit trails.
  • →Mentored junior developers on SOLID, code review, and unit testing.
Jan 2022 — Dec 2024

DataSoft Systems Bangladesh Ltd.

Dhaka, Bangladesh | Internal enterprise tools

Software Developer

  • →Delivered 5+ internal operational tools with ASP.NET Core and Blazor, improving business-process visibility across departments.
  • →Optimized SQL queries and stored procedures, reducing report generation from 10 minutes to under 2 minutes (80%).
  • →Built secure RESTful APIs with JWT authentication handling 10K+ daily requests at <200 ms average response time.
  • →Diagnosed and resolved defects across UI, business logic, and database layers.
Jan 2021 — Dec 2021

Self-Employed (Remote)

Remote | Contract backend work

Freelance Software Developer

  • →Delivered ASP.NET / C# backend and SQL Server projects for remote clients, covering API development, schema design, and bug-fix contracts.
04 / projects

Case studies from the hot path.

Problem, approach, result. No theatre—just the engineering decisions that moved the system.

Delivered case/bkash-isms
IS

bKash Integrated Sales Management System (ISMS)

problem

Nationwide sales platform needed to handle 3x peak transaction volume on existing infrastructure.

approach

Index and query-plan optimization across high-traffic paths.

result

Handles 3x peak volume on same infrastructure. Replaced 40-hour monthly manual reconciliation with a 2-hour automated compliance report (~450 person-hours saved/year).

Backend engineer — index and query-plan optimization .NET Core SQL Server MySQL jQuery
Delivered case/justgo
JG

JustGo — Sports Membership & Club Management Platform

problem

Enterprise needed a modular platform serving web + mobile clients across multiple domains and regions.

approach

Modular REST API covering membership, organization, booking, venue, invoice, class, and results domains. Multi-region Adyen payment integration with cart/store-based merchant account resolution.

result

Enterprise-scale platform serving web and mobile clients with multi-region payment support across UK, US, Europe, and Australia. Backend engineering contributions: Adyen integration (ACH, BACS, SEPA, PayTo), query optimization, and audit logging.

Backend engineer — Adyen integration, query optimization, audit logging .NET 9 / .NET Framework 4.8.1 SQL Server Dapper Adyen
Completed (Independent Project) case/edunest
EN

EduNest — Multi-Tenant School Management System

problem

Schools need a multi-tenant management platform with strict data isolation and reliable payment reconciliation.

approach

Built a modular monolith with Clean Architecture (Domain, Application, Infrastructure, API layers). Multi-tenant data isolation on shared infrastructure, Redis distributed caching, RabbitMQ async processing, and a payment CSV export with cent-level reconciliation logic.

result

Multi-tenant school management platform with tenant-level isolation, RBAC (super admin/admin/school-level) with JWT authentication, Redis + RabbitMQ for high-volume operations, and cent-level payment accuracy. Private codebase; architecture walkthrough available on request.

Sole designer and developer .NET 10 Blazor MSSQL EF Core Redis RabbitMQ
In progress (personal project) case/slow-query-radar
SQ

Slow Query Radar

problem

Teams needed a consistent way to find and review slow SQL queries and optimize them.

approach

Collects slow-query data from SQL Server Query Store, analyzes execution plans and T-SQL, and produces copy-paste-ready suggestions, with a Blazor UI and a CLI.

result

Read-only by design: it never applies fixes automatically on production. Private codebase; architecture walkthrough available on request.

Author and developer .NET 8 ASP.NET Core Blazor Server Dapper SQL Server Query Store ScriptDom
case study
05 / toolkit

Tools I reach for deliberately.

No progress bars. Context, constraints, and the right abstraction beat a decorative percentage.

C#ASP.NET CoreDapperEntity Framework CoreSQL ServerRedisRabbitMQClean ArchitectureAdyenAzureJenkins

Backend

C#ASP.NET Core (Web API, MVC, Razor Pages).NET 10 / .NET 9 / .NET Framework 4.8Entity Framework CoreDapperLINQSignalR

Frontend

React.jsAngularBlazorJavaScript / TypeScriptjQueryHTML5CSS3

Architecture

MicroservicesClean ArchitectureModular MonolithMulti-TenancyCQRSRESTful API DesignSwagger / OpenAPISOLIDDesign Patterns

Databases & Caching

SQL ServerMySQLPostgreSQLRedisIMemoryCache / Distributed CachingQuery OptimizationIndexingStored ProceduresSchema Design

Messaging

RabbitMQAsynchronous / Message-Based Processing

Cloud & DevOps

Azure (App Service, Azure DevOps Pipelines)DockerJenkinsCI/CDGit

Security & Payments

JWT AuthenticationRBACAES-256 EncryptionAdyen (ACH, BACS, SEPA, PayTo)Payment Gateway IntegrationAudit Logging

Testing & Practices

xUnitUnit TestingTDDCode ReviewAgile / ScrumGitHub Copilot & AI-assisted development
06 / foundations

Education & certifications

Education

B.Sc. in Computer Science and Engineering

Royal University of Dhaka

2015 - 2019 · CGPA 3.70 / 4.00 (Top 10% of cohort)

Certifications

  • Advanced SQL and Database Optimization (2024)
  • ASP.NET Core Development — BITM & freeCodeCamp (2018)
  • In progress: Microsoft Azure Fundamentals (AZ-900)
07 / writing

Writing

Notes on .NET, architecture and backend engineering.

AI Agent-এর জন্য API: শূন্য থেকে শুরু, .NET ডেভেলপারের শেখার নোট

BNdotnetapiaimcp

কখন Repository, MediatR আর CQRS দরকার — আর কখন Overkill

BNdotnetcsharparchitecture

.NET Folder Structure: A to Z

ENdotnetcorecsharpcleancodearchitecture
More on dev.to →
08 / contact

Have a slow system or a hard integration?

Typically replies within 24h. LetΓÇÖs talk about the constraint before the solution.

Email meLinkedInGitHubChat on WhatsAppdev.to
bd.rakibahasan@gmail.comUTC+6 · local timeBased in UTC+6 (Bangladesh) · flexible to overlap with EU, US and Australia time zonesLanguages: English (Professional, C1) · Bengali (Native) · Arabic (Intermediate)

Immediate to 4 weeks ┬╖ UTC+6 · Overlaps EU, US, Australia