CV Personal Projects Programming Languages Impressum

Stefan Kölle

Senior Software Developer & Software Architect

CV

Senior Software Developer / Senior Software Architect

TENHIL GmbH & Co. KG (08/2022 - Present)

• Developing and managing microservices for various brands.
• Collaborating closely with the Product Owner to create and implement new services.
• Technologies: .NET Core 8, Docker, Azure, Terraform, Uptrends, Sentry, Loki, Quartz.NET.

Senior Software Developer / Senior Software Architect

stellenanzeigen.de GmbH & Co. KG (11/2018 - 07/2022)

• Architecting hosting solutions and migrating services to Azure.
• Implementing a CMS based on Squidex and managing server infrastructure.

Managing Director

Regio-Jobanzeiger GmbH & Co. KG (10/2014 - 12/2017)

Managing Director, CTO

stellenanzeigen.de GmbH & Co. KG (01/2011 - 10/2018)

• Reorganized the company, focusing on performance marketing and core products.
• Implemented the "SmartReach" performance marketing product.
• Significant projects: Multi-brand strategy, founding "Yourfirm" and "Regio Jobanzeiger", integrating "Kalaydo".

CTO, Member of Executive Management

stellenanzeigen.de GmbH & Co. KG (01/2004 - 12/2010)

• Led product management, software development, IT, customer service, and HTML ad creation.
• Introduced agile software development and virtualized all physical servers.

Head of IT / Development

stellenanzeigen.de GmbH & Co. KG (06/2000 - 12/2003)

• Developed a multi-client web frontend and restructured the ad creation process.

Web Developer

IXOS AG (05/1999 - 05/2000)

• Managed web development environment and internal departmental websites.

Education

FH Augsburg - Computer Science (1996 - 1999)

Internships

IXOS AG - Working Student (10/1997 - 04/1999)

• Redesigned the Jukeman website and prepared training rooms for R/3 training.

Personal Projects

Retro Computing

• MiSTer and MiST FPGA Systems for preservation.
• DOS System, Amiga System, and Atari ST System with the environment from the early 90s.

Upgrade of old Atari Mega 4 (2021)

• Gotek Drive
• More RAM
• Alternative TOS ROMs
• SD HDD Adapter

Home Automation (since 2018)

• Arduino/ESP32/Raspberry/Home Automation.
• LED matrix for Date, Time, Weather, and Status messages (Web API).
• Attached Light sensor, DHT22 Temperature Sensor (Web API).
• Every room has its LED matrix.
• dotnet core application (Master on iMac and 4 clients on Raspberry PIs).
• MQTT for message transfer and remote control via Tasmota RF Module (433MHz).
• Evaluation of power meters from washing machine and tumbler.
• Info message when finished on LED matrices.
• MP3 player (e.g., automatic play in the bathroom when the light is on).
• One Raspberry Pi with pilight and RF433 Module for activating remote control power plugs.

Proxmox Server with Various LxC Linux (since 2020)

• pihole
• suricata
• webone
• minecraft bedrock server (multiple instances)
• divoom-rest

Various Docker Systems (since 2016)

• portainer
• nginx
• grafana
• prometheus
• cadvisor
• nodeexporter
• gitae
• stirling-pdf
• stretto
• tubearchivist
• tubesync
• healthchecks
• watchtower

Walk-on Song (2019)

• When someone enters the office, their jingle is played.
• ESP32 scans WiFi, if a known device is found for the first time per day, the jingle is played.
• MP3 Module for playback on attached speaker.

Kids RFID MP3 Player (2018)

• Interactive audio playback system utilizing RFID technology.
• Powered by an Arduino Nano for compact and efficient operation.
• Plays specific audio files when RFID-tagged objects or cards are placed on the device.
• Designed for simplicity and intuitive use, suitable for all ages.
• Customizable: users can upload and assign personalized audio content to RFID tags.
• Ideal for educational and entertainment purposes.

Dotnet Community Activity (2009 - 2011)

• Attended multiple .NET Open Spaces, including Ulm 2009 and Leipzig 2009.
• Developed a schema-less object storage system named StupidDB.
• Contributed to a developer blog with colleagues.
• Actively participated in Coding Dojos at AutoScout24.

Owner & Developer, inseco.de (2003 - 2008)

• Managed approximately 20 clients, primarily from the gastronomy and club sectors.
• Developed a CMS system for maintaining their websites, programmed in PHP and MySQL.
• Included modules for photo galleries, menus, and events.

Home-Network Projects during IT Manager Phase (2000 - 2006)

• Set up a home network with various Linux servers and Windows NT 4.0.
• Implemented a predecessor to the pfSense firewall.
• Managed a FreeBSD server with Apache, Sendmail, and Perl scripts.
• Maintained an NT 4.0 file server.
• Administered Windows 98 and Windows 2000 hosts.
• More info at moonweb.org/network/

Mailbox/Fidonet (1994 - 2000)

• Operated a BBS and Fidonet Node.
• Managed a node in Augsburg with an uplink directly to the NC in Munich.
• Software was running on an OS/2 computer
• Utilized 2x ISDN and 1x MODEM connections.
• Had about 20 subnodes and points.
• Served as the Bavaria HUB/HOST for various old networks.
• Developed several small software tools in Turbo Pascal for DOS.

PC Intro / Game / Software Development (1992 - 1994)

• Released Phobia Welcome Intro (Sourcecode/Picture/Video) for 486 PC in 1994
• Released Tr@anceMission Intros (Sourcecode/Pictures/Videos) in 1992 and 1993
• Developed Turbo Pascal Graphics Library X-Lib Unit (Sourcecode)
• Used Turbo Pascal and inline assembler for Development

Atari ST Software Development (1990 - 1992)

• Completed game 'Atom oh no' in 1992 (GFA Basic)

Programming Languages

BASIC

• Gained initial experience with BASIC on the EPSON HX-20 in 1988 and Atari ST in 1989.
• Developed two small games (Bowling, LiveStyleCity) using OmicronBasic.
• Created games such as AtomOhNo (an Atomix clone) and TOPchangethecolor with GFA-Basic and TOPpack.
• Produced graphic demos on the Atari ST around 1991.
• Developed simple programs using Amiga Basic in 1991.
• Studied BASIC for two years in school (1991-1992), including coding a Snake clone during class.

C

• First encountered C on the Atari ST in 1992, creating simple programs with Pure C, an advanced version of Turbo C.
• Completed one semester of C during studies in 1997.

Assembler

• Began learning Assembler on the Atari ST in 1992, creating simple programs with Pure Assembler, part of the Pure C Pack.
• Developed a small text mode demo with sound using DevPAK.
• Gained experience on PC in 1994, creating four demos using inline assembler in TurboPascal.

PASCAL

• Started with PASCAL on PC in 1993, using TurboPascal 6.0, 7.0, and Borland Pascal 7.0.
• Developed DOSMENU software for DOS PCs and tools for Fidonet.
• Created two games: a Wheel of Fortune clone and a two-player Tetris.
• Studied PASCAL for one year in school (1994) and one semester on UNIX (Solaris) during studies in 1996.

C++

• First used C++ on PC (Windows) in 1997.
• Worked on an R/3 Integration Project during practical work at iXOS Software AG.
• Completed one semester of C++ on UNIX (Solaris) during studies in 1998.

Java

• Began using Java on PC (Windows) in 1998.
• Participated in a Security Hash Team Project at iXOS Software AG, developing the Java frontend.
• Utilized development environments such as Kawa and IBM Visual Age.

ASP-Classic

• Started with ASP-Classic on PC (Windows) in 1999 while working as a web developer at IXOS AG.
• Managed the web development environment and built internal departmental websites.
• Introduced search functions, request systems, and link checkers to optimize web servers.
• Developed a Visual Basic application for generating static web pages.
• Designed and implemented a workflow for maintaining the website using ASP scripts and SQL databases.
• Led the IT and development department at stellenanzeigen.de GmbH & Co. KG from 2000 to 2003, migrating applications from idc/htx to ASP-Classic and developing a multi-client web frontend for newspaper publishers.

PHP

• Developed a website CMS system (activetool.de) for multiple clients from 2003 to 2008.
• Created a PHP Ticketing System and worked with MySQL databases.

.NET Framework

• Gained experience with the .NET Framework between 2004 and 2010 as CTO at stellenanzeigen.de GmbH & Co. KG.
• Led the migration from ASP Classic to the .NET Framework.
• Hosted applications on Windows IIS and used MSSQL as the database.
• Split software into different layers and enabled communication via SOAP web services.
• Introduced TDD and DDD, and engaged with the .NET community through OpenSpaces and CodingDojos.

.NET Core

• Intensively worked with .NET Core starting in 2018 at stellenanzeigen.de GmbH & Co. KG and continued at TENHIL GmbH & Co. KG from 2022.
• Migrated old VB and ASP-Classic applications to modern .NET Core applications.
• Planned and implemented hosting architecture on Azure.
• Introduced a CMS based on Squidex.
• Developed new multi-client microservices for all brands using .NET Core 8, Docker, Terraform, Azure WebApps, Azure Tables, Azure Blobs, Uptrends, Sentry, Loki, and Quartz.NET.
• Created microservices including Jobs Per Mail, JobApply application service, GeoService, Feedexporter, and Salary Data Service.

Impressum

Stefan Kölle
Neumarkter Str. 86c
81673 München

Phone/Fax: +49-(89)-38151811
E-Mail: [email protected]