10+ YEARS IN BACKEND

S. M. Sazedul
Haque

Backend Software Engineer — Python, distributed systems, event-driven architecture

I build the systems that hold up when the catalogue is 400 million rows deep. Ten years of Python backends across cross-border e-commerce, fintech, IoT and healthcare — designing event-driven services with DDD and CQRS, running idempotent migrations against live data, and leading teams that ship them.

10+
Years Engineering
400M+
Listings at Scale
8
Companies & Products
85%
API Test Coverage

Where I've Built

Eight roles, mostly remote, mostly Python — from leading a UNICEF platform team in Dhaka to re-engineering eBay compliance pipelines for a Warsaw product team.

Backend Software Engineer at Webinterpret
Dec 2025 — Present Warsaw, Poland · Remote contract

Webinterpret lets eBay sellers go cross-border by translating and listing their inventory on international eBay sites — catalogues ranging from a few million to 400M+ listings.

  • eBay inventory compliance & seller self-service: re-engineered how listings are blocked and unblocked across catalogues of up to 400M+ items. Extended the compliance rules engine, ran a resumable, idempotent backfill (dry-run, canary, throttling) and built VeRO brand self-service for sellers.
  • Churn & retention platform: built subscription-cancellation flows across Users, Finance and CRM services with Chargebee and Salesforce webhooks — multi-service cancellation, retention offers, account pause and trial churn — plus SLA alerts auto-creating Zendesk tickets for Gold/Silver sellers and Grafana churn-funnel dashboards.
  • Seller health score (churn prediction): built a rule-based scoring engine (−100 to +100) over data-warehouse metrics with admin-editable cached weights, daily ranking recalculation and churn-risk signals — price swings, spikes in manually ended listings, volume guardrails. Managers filter by segment and bulk-create Zendesk tickets.
  • Seller-to-agent scheduling: integrated Google Calendar push notifications (incremental sync) and Salesforce agent-assignment webhooks so sellers book topic-based calls with their assigned Customer Care agent; service-to-service auth secured via Vault.
  • GPSR compliance: built services to extract and track sellers' EU General Product Safety Regulation status across eBay marketplaces.
  • Architecture & quality: services communicate through event-driven messaging (RabbitMQ) following DDD, CQRS and the repository pattern; each is backed by unit and integration tests and monitored with Sentry and Grafana.
Python FastAPI Pyramid Django PostgreSQL MongoDB Elasticsearch RabbitMQ SQLAlchemy / Alembic Docker Kubernetes / Helm Vault Grafana Sentry DDD · CQRS Chargebee Salesforce Zendesk
Senior Backend Python Developer at Betafore
Dec 2024 — Dec 2025 Remote contract
  • Worked on Smart Invoice/Documents, a product automating document processing and invoicing workflows.
  • Developed backend services for document parsing, classification and data extraction.
  • Integrated OCR tooling and REST APIs for real-time document validation.
  • Streamlined workflows for a 30% reduction in processing time for invoices and documents.
Python Django PostgreSQL Celery Redis Docker OCR AWS S3
Backend Python Developer at Spartan Development d.o.o
Mar 2024 — Oct 2024 Ljubljana, Slovenia · Remote
  • Developed an eBay-type auction platform with scalable APIs — pagination, filtering, ordering.
  • Managed dynamic vehicle data via JSON schema, with auction notifications over WebSocket.
  • Used Docker for development, Celery and Redis for background tasks.
  • Reached 85% API test coverage with Django's test framework and PyTest.
Python Django Docker Celery WebSocket Swagger PyTest Locust Sentry
Technical Lead, Python at RISE UP LABS
Mar 2022 — Feb 2024 Dhaka, Bangladesh
  • Led a team building enterprise web applications for UNICEF projects on open-source platforms — RapidPro and IoGT, integrating Cranky Uncle.
  • eCook V3: architected and developed an IoT platform to replace angaza.com.
  • Built an Employee Management System with fingerprint device integration, project time tracking and leave management.
Python Django Docker Celery MQTT AWS IoT Lambda · SNS · EC2 MongoDB PostgreSQL
Senior Backend Engineer at MIADVG LLC
Apr 2020 — Jan 2022 Dhaka, Bangladesh
  • Built a complex fintech tax-filing platform, integrating Experian, Plaid and Twilio.
  • Implemented form autocompletion from credit reports and bank transactions, inferring filing type, profession, salary and expenditures.
  • Summarised asset data from credit reports — properties, vehicles, loan statuses.
  • Led the transition from a monolith to microservices, improving scalability and availability.
Python Django FastAPI MongoDB PostgreSQL Elasticsearch Celery Docker Kubernetes Jenkins PyTest Sentry
Senior Software Engineer at Strativ AB
Mar 2019 — Apr 2020 Dhaka, Bangladesh

Healthcare and legal applications, focused on data management, workflows and client efficiency.

  • Dermly: features for a medical app identifying potential cancer from body spots.
  • LegalRoom: a web app for legal firms — client onboarding, case management, lawyer time tracking.
  • Vaccina: a cloud-based medical record system with a scalable backend and third-party integrations for healthcare personnel.
  • Doctify: patient data management workflows, improving usability and information flow.
Python Django PostgreSQL Jenkins BankID Sentry
Senior Python Developer at Zero Gravity Ventures Ltd
Apr 2018 — Mar 2019 Dhaka, Bangladesh
  • Built a synchronisation module between Magento and Odoo for real-time product updates and order processing.
  • Developed a reporting module generating and sending monthly due reports to B2B clients.
  • Enhanced Odoo workflows to improve operational efficiency across business functions.
Python Odoo PostgreSQL ReactJS Sentry
Senior FullStack Developer (Lead) at Maison Mahdil
Jun 2016 — Apr 2018 Dhaka, Bangladesh
  • Developed e-commerce and custom web applications — vivretonquartier, copacabanon.com, Letsfit24 and Simple Life Cars — with Django, REST APIs, ReactJS and React Native.
  • Led delivery through Agile sprints against business objectives.
Python Django PostgreSQL ReactJS React Native

What I Work With

Python first, with the data stores, message brokers and infrastructure that event-driven services need around them.

🐍

Languages & Frameworks

  • Python
  • JavaScript
  • Django
  • FastAPI
  • Pyramid
  • Django Channels
  • ReactJS
🗄️

Data & Messaging

  • PostgreSQL
  • MongoDB
  • Elasticsearch
  • Redis
  • RabbitMQ
  • Celery
  • MQTT
  • WebSocket
☁️

Infrastructure & Cloud

  • Docker
  • Kubernetes / Helm
  • AWS EC2 · RDS · S3
  • AWS IoT Core · Lambda · SNS
  • Vault
  • Firebase
  • Jenkins
🏗️

Architecture & Practice

  • Domain-Driven Design
  • CQRS
  • Event-Driven Microservices
  • Repository Pattern
  • PyTest · Integration Testing
  • Technical Leadership
🔌

Integrations

  • Chargebee
  • Salesforce
  • Zendesk
  • Google Calendar API
  • Experian · Plaid · Twilio
  • Magento · Odoo
  • BankID
📊

Observability

  • Grafana
  • Sentry
  • Locust
  • Swagger / OpenAPI

Academic Background

🎓

B.Sc. in Electronics & Communication Engineering

University of Information Technology & Science — Dhaka, Bangladesh

CGPA 3.33 / 4.00
📐

Diploma in Electronics Engineering

Ahsanullah University of Science & Technology — Dhaka

First Division

Let's talk about
your backend.

Architecture reviews, scaling problems, or a team that needs a hand shipping — happy to hear about it.

Download Full CV (PDF)