Marcus Kühl - Senior Software Developer (APEX)

Q: Where is Marcus based?

Marcus is based in Berlin, Germany and can operate in on-site , hybrid , and remote work models.

Q: What languages does Marcus speak?

Marcus speaks the following languages: German (Native), English (Advanced), Spanish (Intermediate) .

Q: How many years of experience does Marcus have?

Marcus has at least 20 years of experience. During this time, Marcus has worked in at least 8 different roles and for 11 different companies . The average length of individual experience is 2 years and 6 months . Note that Marcus may not have shared all experience and actually has more experience.

Q: What is Marcus's latest experience?

Marcus's most recent position is Senior Software Developer (APEX) at Various .

Q: What companies has Marcus worked for in recent years?

In recent years, Marcus has worked for Various and Digital Funding Platform .

Q: Which industries is Marcus most experienced in?

Marcus is most experienced in industries like Pharmaceutical , Information Technology (IT) , and Government and Public Administration . Marcus also has some experience in Manufacturing , Healthcare , and Telecommunication .

Q: Which business areas is Marcus most experienced in?

Marcus is most experienced in business areas like Information Technology (IT) , Quality Assurance (QA) , and Business Intelligence . Marcus also has some experience in Product Development .

Q: Which industries has Marcus worked in recently?

Marcus has recently worked in industries like Information Technology (IT) and Government and Public Administration .

Q: Which business areas has Marcus worked in recently?

Marcus has recently worked in business areas like Information Technology (IT) and Product Development .

Recommended expert

Berlin, Germany

Experience

May 2025 - Present

10 months

Senior Software Developer (APEX)

Various

Further development and tuning of a mid-sized application for event and participant management
Identification of bottlenecks
Addition of missing foreign keys and indexes
Reprogramming of views and SQL queries in APEX
Report development with Jasper Reports
Mentoring other APEX developers

Jan 2021 - Aug 2024

3 years 8 months

Lead Software Developer (APEX)

Digital Funding Platform

Development of a very large application for online EU funding applications
Development and presentation of a prototype
Making application design decisions in cooperation with the requirements engineers
Development of supporting applications, e.g., for application configuration and management of application processes
Designing key parts of the application, e.g., user guidance, dynamic menu specific to funding applications, configurable uploads, generation of the funding application summary
Customizing the application's CSS layout, introducing suitable classes for global styling
Development of complex views using SQL views
Guiding APEX developers
Point of contact for requirements engineers and business users on feasibility of requirements in APEX

Sep 2020 - Oct 2020

2 months

Consultant

Development of a Pharmacovigilance Intelligence Tracking System

Development of a prototype for a pharmacovigilance application in APEX 20.1
Creating the database and APEX application in the Oracle Cloud
Alert inbound screen with faceted search and file upload for document attachments
Simple impact assessment workflow with signature section
Email sending
Dashboard and calendar
Two-hour presentation of the prototype and basic APEX architecture

Jan 2014 - Jan 2020

6 years 1 month

Senior Software Developer

Roche Basel

Documented DWH reports, e.g., for health authorities
Implementing medical queries in DWH queries, such as event search with MedDRA terms and classification (LLT, PT, HLT, HLGT, SOC), primary path/multipath
Unexpected events based on different labelings such as IB, CDS, EUSPC, or country-specific labeling information
SUSAR cases for specific countries, drugs, events, studies
SMQs (Standard MedDRA Queries) and Algorithmic MedDRA Queries (ABC terms)
SQL tuning and complex regex searches in case narratives
Application development with Oracle Application Express (APEX)
Validations, code reviews, tuning, and documentation
GVP training (Good Pharmacovigilance Practices)
International project (project language English)

Jan 2012 - Dec 2013

2 years

Senior Software Developer, Tester

Siemens AG

Development of various test programs for the European Train Control System (ETCS)
Module, integration, and validation tests
Code reviews and specification reviews
International project (English and German)

Jun 2010 - Mar 2012

1 year 10 months

Senior Software Developer

Roche Basel

Collaborated on the concept and implementation of a new flat table datamart with SCD Type II
Validation documentation (UR, SDS)
Programming of load jobs
View layer generation
PL/SQL packages to support reporting
Migration of various reports and SQL tuning
Reports based on the requirements of the business department

Jan 2010 - Apr 2010

4 months

Senior Software Developer

Kassenärztliche Vereinigung Bayern

Development of an Oracle Application Express application to form audit groups for practice comparisons in the economic efficiency audit
Authentication via MS Active Directory (LDAP)
Proxy user, session state protection and encryption
Generator for online help
SQL tuning
Setup of database jobs to load the required data from the doctor directory
Input validation with Oracle regular expressions
Report development

Jul 2008 - Jun 2009

1 year

Senior Software Developer

T-Mobile

Technical design of data storage and processing for SMS and email delivery and DWH export
Data model extension
Implementation of web services in C++ and PL/SQL
MFC GUI development
Technical documentation and operation manuals

Sep 2006 - Jul 2008

1 year 11 months

Software Developer

Boehringer Ingelheim

Creation of validation documentation such as requirement and software design specifications, installation plans, traceability matrix, etc.
Specification, development and documentation of a reporting application for legacy data using Oracle Application Express 3.0
Analysis of migration scripts from the software vendor and database-level analysis of migration errors
Development of distribution rules in PL/SQL (distribution rules)
Planning and execution of migration tests

Jun 2006 - Sep 2006

4 months

Software Developer

Imaging Solutions AG

Creation of a UML class model
Implementation using internal libraries, librsvg and Cairo plugin
Development of a Gnome virtual file system module
Porting of existing libraries to Linux
Documentation with Doxygen

Apr 2005 - Jun 2006

1 year 3 months

Software Developer

Kassenärztliche Vereinigung Bayern

Development of the KVB doctor directory
Development and further development of various other applications
Report development

Mar 2002 - Sep 2002

7 months

Software Developer C++

Heidelberger Druckmaschinen AG

Concept, design and implementation of a CORBA subscription server (observer pattern)
Persistent storage management based on memory-mapped files
Development of several CORBA clients for testing and editing
Functional and load testing
Documentation

Jun 2001 - Jan 2002

8 months

Software Developer (Oracle)

Banken und Sparkassen

Takeover, customization and migration of an Oracle 7.3 batch application
Analysis and documentation of job control for PL/SQL code and database objects
Cleanup of the existing data model
Testing and adapting the new model, ensuring interface consistency
Setting up multiple Oracle instances for development, testing and production
Migration to Oracle 8.1.6
Maintenance of the new production environment
Tuning measures (redo logs, indexes, RBO/CBO)
Support for the euro conversion

Industries Experience

See where this freelancer has spent most of their professional time. Longer bars indicate deeper hands-on experience, while shorter ones reflect targeted or project-based work.

Experienced in Pharmaceutical (9.5 years), Information Technology (4.5 years), Government and Administration (3.5 years), Manufacturing (2.5 years), Healthcare (1.5 years), and Telecommunication (1 year).

Pharmaceutical

Information Technology

Government and Administration

Manufacturing

Healthcare

Telecommunication

Business Areas Experience

The graph below provides a cumulative view of the freelancer's experience across multiple business areas, calculated from completed and active engagements. It highlights the areas where the freelancer has most frequently contributed to planning, execution, and delivery of business outcomes.

Experienced in Information Technology (19.5 years), Quality Assurance (10.5 years), Business Intelligence (9 years), and Product Development (7 years).

Information Technology

Quality Assurance

Business Intelligence

Product Development

Summary

Senior Oracle Developer, Senior APEX Developer

Skills

Oracle Database Oracle 7 – 23
Oracle Cloud Autonomous Database (Oci)
Oracle Application Express - Apex Version 3 To 24.2
Development Of Apex Applications
Tuning Of Apex Applications
Gui Design, If Needed, In Coordination With The Client's Departments
Development Of Very Complex Pages (E.g. Hierarchical Views With Grouping At Different Levels, Reports With Special Layouts, Dynamic Application Menus)
Development Of Report Templates
Development Of Template Components
Restful Data Services
Rest Data Sources (Open Api Definitions, Postman)
User-defined Authentication / Authorization
Single Sign On (Ldap), Social Sign In
Dynamic Actions
Javascript, Css, Html
File Upload/download, Excel Import
Apex Universal Theme
Customization And Development Of Apex Templates
Mail Templates, Email Sending
Sql - Over 20 Years Of Oracle Sql Experience
Setup Of Schemas
Database Links, External Tables, External Functions
Analytic Functions
Hierarchical Queries
Xml/sql Table Mapping
Tuning By Analyzing Execution Plans
Reprogramming Of Sql Queries
Sql Hints
Index Visibility
Functional Indices
Pl/sql - Over 20 Years Of Pl/sql Experience
Sql Generation (E.g., Migration Scripts, Views, Or Programs)
Dynamic Functions Using Cursor Variables
Autonomous Transactions
Exception Handling
Working With Pragmas
Encryption
Courses With Steven Feuerstein

Languages

German

Native

English

Advanced

Spanish

Intermediate

Education

Dipl. Geologist · Geology

Profile

Created

August 2025

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Frequently asked questions

Do you have questions? Here you can find further information.

Where is Marcus based?

Marcus is based in Berlin, Germany and can operate in on-site, hybrid, and remote work models.

What languages does Marcus speak?

Marcus speaks the following languages: German (Native), English (Advanced), Spanish (Intermediate).

How many years of experience does Marcus have?

Marcus has at least 20 years of experience. During this time, Marcus has worked in at least 8 different roles and for 11 different companies. The average length of individual experience is 2 years and 6 months. Note that Marcus may not have shared all experience and actually has more experience.

What roles would Marcus be best suited for?

Based on recent experience, Marcus would be well-suited for roles such as: Senior Software Developer (APEX), Lead Software Developer (APEX), Consultant.

What is Marcus's latest experience?

Marcus's most recent position is Senior Software Developer (APEX) at Various.

What companies has Marcus worked for in recent years?

In recent years, Marcus has worked for Various and Digital Funding Platform.

Which industries is Marcus most experienced in?

Marcus is most experienced in industries like Pharmaceutical, Information Technology (IT), and Government and Public Administration. Marcus also has some experience in Manufacturing, Healthcare, and Telecommunication.

Which business areas is Marcus most experienced in?

Marcus is most experienced in business areas like Information Technology (IT), Quality Assurance (QA), and Business Intelligence. Marcus also has some experience in Product Development.

Which industries has Marcus worked in recently?

Marcus has recently worked in industries like Information Technology (IT) and Government and Public Administration.

Which business areas has Marcus worked in recently?

Marcus has recently worked in business areas like Information Technology (IT) and Product Development.

What is Marcus's education?

Marcus attended education in Geology.

What is the availability of Marcus?

Marcus is immediately available full-time for suitable projects.

What is the rate of Marcus?

Marcus's rate depends on the specific project requirements. Please use the Meet button on the profile to schedule a meeting and discuss the details.