Mahmudul Islam

Software Engineer, backend & full-stack

Mahmudul Islam

I build production web software from the data model to the UI.

Software engineer with an M.Sc. in Computer Science and 5+ years of shipping web applications. I design REST APIs in Python/FastAPI and NestJS on PostgreSQL, build frontends in Next.js, React and SvelteKit, and put LLM and RAG features into live products. Currently at CIVIS.digital in Celle.

Download CV (PDF) Email me

LinkedIn GitHub dev.mahmudislam@gmail.com

Results from recent roles

  • 70 %more users on the SO12 dashboard after I modernised it
  • 80 %faster checkout after the Stripe integration
  • 80 %fewer login support tickets after a central login system
  • 1,800+freelance hours, Top Rated, 100 % job success on Upwork

Experience

  1. 03/2026 – today

    Software Engineer, backend & frontend

    CIVIS.digital GmbH, Celle

    • Integrated LLM and RAG services into the MeinLeistungsCheck chatbot, giving people a quick social-benefits check in plain language.
    • Built a central rule engine that unifies complex benefit calculations for an ESF-funded platform, working closely with social workers as domain experts.
    • Own subscription billing end to end: relational data model, backend logic and UI.
    • Modernised the SO12 dashboard; new features and fixes grew its user base by about 70 %.
    • Introduced automated and end-to-end tests with Jest across several projects.
    • Python
    • NestJS
    • Next.js
    • PostgreSQL
    • Jest
    • Azure
    • LLM/RAG

  2. 01/2025 – 02/2026

    Software Developer

    ICS Sustainable Solutions GmbH, Flensburg

    • Developed and operated Python/FastAPI microservices, including deployment and configuration via GitLab CI.
    • Integrated Stripe via REST, cutting checkout time by 80 %; redesigned the order workflow, raising throughput by 50 %.
    • Built a SvelteKit customer portal with improved search.
    • Python
    • FastAPI
    • PostgreSQL
    • SvelteKit
    • Docker
    • GitLab CI

  3. 01/2024 – 12/2024

    Full-Stack Developer (working student)

    Digital Medical Academy, Stuttgart

    • Built a central login system, reducing recurring support tickets by about 80 %.
    • Replaced a manual process with a serverless, event-driven certificate generation and storage pipeline on Azure.
    • Set up Terraform infrastructure as code, GitHub Actions CI/CD and Datadog monitoring.
    • React
    • Node.js
    • TypeScript
    • Azure Functions
    • Terraform
    • GitHub Actions
    • Datadog

  4. 10/2021 – 09/2022

    Web Developer (student assistant)

    Universität Rostock, Rostock

    • Replaced a hard-coded publication system with a configurable, database-backed web portal that staff maintain without code changes; ran the Linux server stack.
    • PHP
    • MySQL
    • JavaScript
    • Linux
    • Apache

  5. 10/2019 – 10/2023

    Freelance Full-Stack Developer

    Upwork, remote

    • Top Rated with 100 % Job Success across 30+ international clients and 1,800+ hours: web apps, API integrations, data imports and database migrations.
    • PHP
    • Ruby on Rails
    • JavaScript
    • MySQL

Skills

Languages
Python, TypeScript, JavaScript, SQL, PHP, Bash
Backend & APIs
FastAPI, NestJS, Node.js, REST API design, Microservices, RabbitMQ
Frontend
Next.js, React, SvelteKit, HTML/CSS, Responsive UI
AI & LLM
LLM integration, RAG pipelines, Chatbots in production
Databases
PostgreSQL, MySQL, MongoDB, Data modelling, Schema migration
Cloud & DevOps
Docker, Terraform, Azure, AWS, GitLab CI, GitHub Actions, Datadog, Linux
Quality
Jest, End-to-end tests, Code review, Documentation, Git
Integrations
Stripe, Third-party APIs, Event-driven imports

Education

M.Sc. Computer Science

Universität Rostock, 2025

Thesis: reverse engineering existing databases into explicit relational models.

Certificates

  • HackerRank: SQL (Advanced)
  • HackerRank: REST API
  • HackerRank: JavaScript
  • Upwork Top Rated Web Developer

What colleagues say

“Consistently demonstrated exceptional technical ability, strong problem-solving skills, and a deep understanding of modern software development practices.”
Kenneth Liedtke
CEO, ICS Sustainable Solutions GmbH
“He was reliable and competent in always finding solutions and answers.”
Johannes Michael Ossadnik
Research associate, Universität Rostock

Latest writing

All posts

  1. Correlation IDs: following a request across services

    When a request hops through a gateway, a few services and a worker, a shared ID is what lets you reconstruct what happened. Here is a simple way to pass one.

    2 min read

  2. The transactional outbox: saving data and publishing events reliably

    Writing to the database and publishing a message are two separate steps that can fail independently. The outbox pattern turns them into one transaction.

    3 min read

  3. Circuit breakers: failing fast when a dependency is down

    When a downstream service is struggling, waiting on it makes things worse. A circuit breaker stops calling it for a while so both sides can recover.

    3 min read

Get in touch

I read every message and usually reply within a day. Email works best; I am also on LinkedIn.

dev.mahmudislam@gmail.com LinkedIn Download CV (PDF)