Denis Hamann - Architect & Senior Cloud Developer - NEO OCR

Hamburg, Germany

Experience

Jul 2022 - Present

3 years 1 month

Architect & Senior Cloud Developer - NEO OCR

Santander Consumer Technology Services GmbH

In the financing business, capturing customer documents is a key back-office task. By automatically reading IDs and various forms, significant time savings can be achieved.
Denis led the design and implementation of a cloud-based OCR system for classifying documents in the sales process and structuring them via REST APIs in AWS. His tasks included architecture design, stakeholder communication, and proactive compliance coordination.
Kotlin
Java
Gradle
AWS Lambda
AWS Rekognition
AWS Textract
AWS DynamoDB
AWS DocumentDB
AWS MQ
AWS
MongoDB
Docker
Kubernetes

Jan 2020 - Sep 2022

1 year 9 months

Senior Backend Developer - Order Management - Sourcing

MediaMarktSaturn Group

The existing order management system was a bottleneck for future growth of MMS’s online business. To boost warehouse throughput and lower logistics costs, new features (e.g. Nearest Regional and Round Robin Sourcing) were needed. The new system would handle thousands of delivery commitments per second.
Denis was responsible for designing and implementing a new sourcing microservice in a hexagonal architecture based on Domain-Driven Design patterns. He introduced modern development practices (CI/CD, Clean Code coaching, etc.), collaborated with other teams to align APIs and events, and coordinated with enterprise architects on interface integration across domains.
Kotlin
Java
Spring Boot
Maven
Gradle
Grafana
Google Cloud Platform
MongoDB
Cloud SQL
CloudBuild
PostgreSQL
Docker
Docker Compose
Kubernetes
Microservices
Hexagonal Architecture
Domain Driven Design (DDD)

Oct 2020 - Mar 2021

6 months

MongoDB Specialist - Mongo Cluster Upgrade & Optimization

Techniker Krankenkasse

Denis migrated an existing MongoDB cluster to the latest version, simplified the setup, and added IaC patterns.
MongoDB
Migration
Clustering
Backups
Infrastructure as Code
Sharding
Replicasets

Oct 2019 - Dec 2020

1 year 3 months

Germany

Senior Backend Developer, DevOps - Partner Platform

Otto GmbH & Co KG

OTTO is one of Germany’s largest e-commerce platforms, offering millions of customers a wide range of products from fashion to furniture.
The data management team processes raw product data, enriches it with store-specific info, and makes it available to other teams who present it to customers on Otto.de. Central data distribution provides many benefits but also challenges, like handling large data volumes, sync issues, and timely distribution. The platform is a distributed system of about 30 microservices, each building parts of the product data.
Denis helped build multiple new microservices to support new data sources for the upcoming partner platform. As new partners joined, he led architecture design and service implementation, integrated and redesigned existing platform processes, held talks with platform stakeholders and partner system developers, and integrated services into the AWS environment.
AWS
AWS CLI
AWS CloudWatch
AWS CloudFormation
AWS EC2
AWS IAM
AWS Lambda
AWS S3
Java
Amazon Kinesis
Jenkins
Spring Boot
Spring Data JPA
AWS SQS
AWS SNS
Event Sourcing
AWS ECR
MongoDB
Microservices

Jul 2018 - Sep 2019

1 year 3 months

Germany

Backend Developer, DevOps - MMDB-Switch

Otto GmbH & Co KG

Denis helped develop multiple new microservices to replace a legacy monolith. He took a lead role in architecture design and implementation, including discussions with stakeholders and backend developers, API design and testing, service code implementation, launch validation, and follow-up with other teams.
AWS
AWS S3
Spring Boot
Microservices
IntelliJ IDEA
OAuth 2.0
AWS Lambda
Continuous Deployment
Continuous Integration
Security
Cloud Services
Grafana
Kibana
Elasticsearch
Gradle
Jenkins
MongoDB

Apr 2018 - Sep 2018

6 months

Germany

Backend Developer, DevOps - AWS Migration

Otto GmbH & Co KG

Denis was part of the migration from an externally hosted infrastructure to AWS, moving about 30 microservices to the Amazon cloud. The project also optimized the architecture by introducing serverless Lambdas and Kinesis. He took on full-stack and DevOps tasks (routing, user management, network peering, etc.) to build the AWS setup from scratch.
Microservices
Java
AWS
Jenkins
MongoDB
AWS S3
AWS CloudFormation
IntelliJ IDEA
REST
Spring Boot
AWS EC2
AWS CloudWatch
AWS Lambda
Amazon Kinesis
Cloud Services
AWS ECR
Kibana
Grafana
Elasticsearch
Python
Bash Script
Apache Kafka
DevOps
Docker
Continuous Delivery
Continuous Integration
Trunk Based Development

Jan 2016 - Mar 2018

1 year 3 months

Germany

Android Developer - yomo

Star Finanz GmbH

Star Finanz GmbH is part of Finanz Informatik and a leading German provider of multibanking online and mobile payment solutions for the Sparkasse group.
Several Sparkassen partnered with Star Finanz to develop YOMO, a mobile app for managing a bank account.
Denis joined as an Android developer to deliver app features and use his mobile expertise to improve product quality. He introduced a test culture with automated unit and UI tests integrated into CI, advised on stress-test approaches, and helped migrate the codebase to Kotlin.
Kotlin
Java
Espresso
Jenkins
Bitbucket
Confluence
JIRA
sympli
Invision
Android
Calabash

Apr 2016 - Dec 2016

9 months

Hamburg, Germany

Mobile Developer

Norddeutscher Rundfunk

Norddeutscher Rundfunk (NDR) is a public broadcaster based in Hamburg, also serving Lower Saxony, Mecklenburg-Vorpommern, and Schleswig-Holstein. It’s part of the ARD network and runs multiple radio and local TV programs.
NDR wanted a modular app platform for radio and TV channels to share code while keeping each channel’s branding. The challenge was large data volumes, sync, and timely updates.
Denis helped deliver needed features by applying his web and native mobile experience for Android and iOS. He introduced a test culture with unit and component tests integrated into CI, improving build processes and quality to launch the first radio app on time.
Angular JS
Typescript
Karma
Jasmin
Calabash
Java
Objective C
nodeJS
Android
iOS
Cordova
Ionic

Apr 2016 - Jun 2016

3 months

Web Developer, Consultant

myDriver

myDriver is a Sixt startup offering B2B and B2C transport services via a platform that connects customers with chauffeur service cars at taxi prices. Bookings are made via app or website and paid cashless.
Denis analyzed ongoing database issues in myDriver’s BI team, advising technically and organizationally. He improved architecture by building a modern single-page app with Angular JS and Bootstrap, leveraging the existing data warehouse. His work greatly boosted database and BI performance.
Angular JS
PHP
PostgreSQL
Bootstrap
RESTful
Apache
SQL

Jul 2015 - Mar 2016

9 months

Consultant, System Architect

Lufthansa Technik

Lufthansa Technik is a leading independent provider of maintenance, repair, and overhaul (MRO) services for aircraft, engines, and components, with 32 companies and over 25,500 employees worldwide.
The VIP & Executive Jet Solutions product line needed a capacity-management app. The existing solution had no workflow management and required heavy support.
After technical and business analysis, Denis led the new implementation. He communicated with stakeholders across departments, refined requirements, evaluated available Lufthansa Technik technologies, and designed an architecture that balanced business needs and tech design. He defined a data migration plan and roadmap.
The result was migrating over 500 users from an old MS Access system to a web-based, LDAP-integrated application, improving IT’s reputation and making Denis a trusted contact for new requirements.
SQL
JavaScript
jQuery
CSS3
HTML
XML
Oracle
Oracle APEX
JIRA
Confluence

Jul 2014 - Mar 2015

9 months

Bamberg, Germany

Developer

Universität Bamberg

The Chair of Computer Science in Cultural Studies researches geogames and their use in education.
The task was to explore ways to create better game boards for geogames using public data. A prototype was needed for evaluation.
Denis researched public data sources, then used OpenStreetMap data to build dynamic game boards. He used Ruby on Rails for the geogame and developed a k-nearest neighbors algorithm to rate boards. He built a web service that used GraphHopper to calculate real walking distances.
The result was a geogame framework for evaluating generated game boards.
SQL
Ruby
jQuery
ActiveRecord
Java
Dijkstra
RESTful
Ruby on Rails
OpenStreetMap
leaflet
GraphHopper
OverpassAPI

Apr 2014 - Sep 2015

1 year 6 months

Consultant, System Architect

Lufthansa Technik

The VIP & Executive Jet Solutions division needed better production planning for parts. Multiple apps existed but none helped decide whether to make or buy a part.
The goal was to assess the existing MS Excel solution and use it as a basis for a new app that would help make the best decision based on resources and production plans.
Denis gathered data from clients and IT, used his manufacturing sector experience to design a two-stage calculation algorithm considering machine load, planned output, and worker availability (e.g. holidays).
The app let the department make data-driven decisions and meet business goals.
SQL
JavaScript
jQuery
Java
C#
Git
Oracle
Oracle APEX
Linux
JIRA
Confluence
Scrum
Icinga

Apr 2014 - Mar 2015

1 year

Mobile Developer

Shinsolutions

Shinsolutions is a startup founded by Denis and a friend, providing white-label apps for offline content delivery.
They aimed to use beacon-like tech to help people find each other in crowds at concerts and festivals.
Denis worked on an app to locate people, focusing on backend communication and Bluetooth interaction. The app helps find lost friends and meet people in unfamiliar places.
Java
Spring
Hibernate
Angular JS
RESTful
Apache
Android

Jul 2013 - Mar 2014

9 months

Mobile Developer

Fewclicks

Fewclicks is a startup in e-commerce expanding its tech to offline stores.
To grow its market, it explored location-based services and beacon technology.
Denis built a proof-of-concept app, analyzed technical options, and liaised with stakeholders. Later, he presented the Android prototype to a clothing chain’s board, winning a contract and leading to a spin-off, Favendo, expanding in the US.
Java
Circular Lateration
BT 4.0/BLE
Android
Ubuntu
Eclipse
IntelliJ

Jul 2013 - Mar 2014

9 months

Bamberg, Germany

Developer

Universität Bamberg

The Chair of Energy-Efficient Systems researches energy use and behavior change methods to save energy.
The task was to develop software that predicts energy consumption classification of unknown households based on given attributes.
Denis used his problem-solving skills to study machine learning algorithms, researched current work, and built a proof of concept with SVM and ANN. He then created a web app using R-Studio.
He designed feature vectors to describe household energy use for training and prediction.
The result was a web service that lets users predict household features (e.g. single household, house size) using a training and a characterization dataset.
SQL
JavaScript
R
Matlab
Machine Learning
SVM
ANN
MSSQL
R-Studio

Jul 2012 - Sep 2013

1 year 3 months

Heilbronn, Germany

Research Assistant

GGS Heilbronn

Denis helped study the influence of shareholders on IT capabilities of S&P 500 companies. He developed custom software and extensive SQL queries to calculate formulas from academic papers.
Tasks included large ETL processes and data aggregation. Denis used his expertise in algorithm optimization and data transformation to enable visual validation of hypotheses discussed in multiple articles.
Java
R
SQL
RESTful webservices
MySQL
Excel

Jul 2012 - Dec 2013

6 months

Germany

Project Manager

Pirelli Deutschland

Pirelli is a multinational tire maker based in Milan, Italy, and the fifth-largest tire producer worldwide, operating in over 160 countries with multiple plants and a broad dealer network.
In Pirelli’s marketing department, Denis was tasked with designing a lounge for premium tire dealers as a project manager.
He managed supplier communication and optimized the delivery process of lounge elements. His experience with challenging clients helped balance company and customer interests.
His work led to a streamlined process and a clear, transparent routine that the sales team could use to offer the lounge as a benefit to Pirelli’s top dealers.
Project Management
MS Project

Apr 2011 - Sep 2011

6 months

Germany

SAP Developer

Pirelli Deutschland

Pirelli wanted to improve the ordering process for its tire dealers by reducing suppliers and getting better prices from a few preferred vendors.
Denis worked as an ABAP developer on a new dynpro for selecting wheel configurations for specific vehicles. This transaction was seamlessly integrated into the POS system.
The SAP transaction used a web view to preview the car with new tires and rims. Using newer tech, Denis gave customers a visually appealing interface despite SAP’s limited options.
The solution was rolled out in all 84 dealerships and reduced the supplier count. Later, procurement closed better deals due to higher volumes.
ABAP
Edifact
Ediwheel
SOAP
Ajax
jQuery

Jul 2010 - Mar 2011

9 months

Germany

Java Developer

Pirelli Deutschland

Pirelli used Cisco software to monitor network hosts but only used a small subset of its features, and license renewal was not cost-effective.
Denis researched SNMP-based host monitoring software. When none fit, he designed and built software from scratch, creating an architecture and algorithm to map hosts to switches in a star hierarchy.
His network infrastructure and Windows-domain knowledge let him combine SNMP data with LDAP info.
The solution integrated into Nagios and let IT locate devices and spot misconnected hosts.
HTML5
CSS3
JavaScript
Java
PHP
SNMP
SQL
ANT
Subversion

Jul 2010 - Mar 2011

9 months

Mobile Developer

Shinsolutions

Shinsolutions, founded by Denis and a friend, delivers white-label app solutions focused on offline content delivery.
The Erbach Castle Association wanted an app for young visitors to connect with local history without giving too much info, so they’d still visit the exhibit.
Denis and his friend built a custom mobile CMS. Denis focused on backend communication and an algorithm to sync only changed files while keeping embedded content. A clear API was key.
The app was featured in a local paper and downloaded by many visitors.
PHP
MySQL
Objective C
RESTful

Jan 2009 - Sep 2010

9 months

Germany

IT Consultant

Pirelli Deutschland

Pirelli needed to report import and export data to the German statistics office per EU rules. Error rates were over 70% and the reporting process and SAP transactions had to be improved.
Denis analyzed the problem and implemented tasks for a better process.
His analytical view identified the most common errors, and he worked with procurement and IT to make changes.
Adjusting SAP transactions reduced manual work and cut the error rate to 3% or less, greatly improving the Intrastat reporting process.
SAP R3

Jul 2009 - Dec 2009

6 months

Germany

Web Developer

Pneumobil

Pneumobil is a Pirelli-owned chain of auto repair and tire shops with 84 locations in Germany, selling and fitting tires and rims.
German regulations require matching the right tires and rims to cars, managed by an MS Access database distributed offline by DVD.
Due to poor performance and outdated data, branches complained about customer advice. The task was to analyze the status quo and build a modern web app.
Denis developed the web app and handled data migration. Because traffic ministry data varied in quality, a migration plan was needed.
A full ETL process was done before moving to the new app, covering quality improvement, transcoding, and extraction.
The final solution replaced the Access database and added a matching feature for slow-selling tires and rims to promote special offers in local papers.
CSS
HTML
ASP.NET
Java
SQL
Windows 2008 Server
MSSQL
MS Access

Jul 2007 - Jun 2008

1 year

Developer

Ralos

Ralos built and supplied solar panels to households.
Denis’s task was to develop software to analyze and display solar energy output. He managed stakeholder communication, working closely with the firmware developer for the modules.
He created software to read solar output over a serial interface and built a web app to display historical data.
The result was a working prototype later integrated into Ralos’s homepage and awarded a local innovation prize.
C++
SQL
PHP
PHP-GD
Visual Studio
PostgreSQL
Curl

Summary

Denis is a very experienced developer with broad experience in IT and implementation projects in both the private and public sectors. He aims for pragmatic, business-focused solutions with as little architectural complexity as possible. He is experienced in backend development and loves solving complex problems in close collaboration with stakeholders. Denis’s way of working is marked by high commitment, goal-oriented thinking, and a relaxed style. He is especially strong at problem solving and working towards goals and deadlines. He prefers working in teams where he can take responsibility and initiative.