Jens Grassel - Scala Backend Developer for eCommerce

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Bergen, Germany

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Experience

May 2023 - Present

3 years 4 months

Shijou GmbH

Software architecture and backend development for a marketplace solution / eCommerce retail
Used Scala, Python, http4s, Next.js, Elasticsearch, PostgreSQL, AWS

Sep 2022 - May 2023

9 months

Toll Collect

Analysis and processing of sensor data
Quality assurance of algorithms within a cluster solution based on Spark, Kafka and Cassandra
Implementation in Scala and Java
Utilized Docker, Scrum, AWS, Google Cloud, Jira and Confluence

Oct 2021 - Aug 2022

11 months

Fashion Digital GmbH & Co. KG

Backend development with Scala and Akka for the Product Data team in the e-commerce division
Further development of the platform using Kotlin and Cloud Bigtable

May 2021 - Sep 2021

5 months

EWE AG

Ported existing REST services and AWS Lambdas to Akka and Apache Spark
Designed and implemented a new AWS infrastructure and new services
Worked with Python, Flask, RabbitMQ, DocumentDB, AWS, microservices, PL/pgSQL, REST APIs, Docker, Kubernetes, CI/CD, GitLab and Scrum

May 2020 - Apr 2021

1 year

Shijou GmbH

Developed a marketplace solution and e-commerce retail platform
Used Scala, Python, http4s, Next.js, Elasticsearch, PostgreSQL, AWS

Jan 2020 - Apr 2020

4 months

Switzerland

Remote

carIT AG

Project planning and system architecture
Backend development with Java, Jenkins and MySQL
Analyzed and audited code of an auto-auction platform based on Java and Spring
Initiated and planned modernization and merging of multiple sub-platforms
Developed a refactoring concept for the entire IT infrastructure including hosting

Mar 2018 - Dec 2019

1 year 10 months

Remote

Parfümerie Douglas GmbH

Maintained and enhanced the online shop based on Play Frameworks and the Hybris e-commerce platform in Java
Introduced functional programming in Scala for backend teams
Developed new services for data integration tasks

Oct 2017 - May 2018

8 months

Project

Centogene AG

Conceptualized and developed a big-data environment for processing large volumes of laboratory measurement data for biomarker analysis
Integrated raw data into processing pipelines using Flink, Cassandra and Kafka

May 2017 - Dec 2017

8 months

Remote

Recogizer Group

Developed new and extended existing microservices in the IoT data domain as a foundation for ML systems

Sep 2016 - Mar 2017

7 months

Remote

Free2Move (Carjump)

Analyzed and enhanced an existing service architecture
Onboarded and supported new developers
Designed and implemented new services based on given requirements

Mar 2015 - Sep 2016

1 year 7 months

Project

The Zene AG

Developed services and search indexes to provide web and image search via REST APIs for a website and an app
Used Scala, Java and Elasticsearch

Jan 2014 - Jun 2015

1 year 6 months

Product Development

Wegtam GmbH

Developed a data aggregation and analysis tool (Tensei-Data)
Built an enterprise search solution (Wegtam Search Agent) using Java and Elasticsearch
Employed Scala, Akka, Play Framework and SQL

Jun 2012 - Present

14 years 3 months

CTO / Founder

Wegtam GmbH

Founded and led the company
Developed Tensei-Data for data integration and the Wegtam Search Agent for enterprise search
Utilized Scala, Akka, Play, Elasticsearch and PL/pgSQL

Feb 2011 - Oct 2013

2 years 9 months

Technical Director

Telematika GmbH

Directed programming and development efforts
Implemented CRM, DMS, ERP, CMS and e-learning systems

Sep 2008 - Jun 2010

1 year 10 months

Project Management

nexico Consulting GmbH

Led projects and programming teams
Worked on data mining, BI and software development

Nov 2006 - Jun 2010

3 years 8 months

Internet services and software development

Freelancer

Provided programming, web application development and consulting services

Mar 2001 - Mar 2005

4 years 1 month

Trainee

Vinci Energies - Controlmatic GmbH

Worked on automation technology, programming and software development

Industry Experience

See where this freelancer has spent most of their professional time.

Experienced in Information Technology, Retail, Energy, Cosmetics, Professional Services, and Fashion.

Information Technology

Retail

Energy

Cosmetics

Professional Services

Fashion

Business Area Experience

See which departments and functions this freelancer has contributed to most.

Experienced in Information Technology, Product Development, Project Management, Business Intelligence, Quality Assurance, and Research and Development.

Information Technology

Product Development

Project Management

Business Intelligence

Quality Assurance

Research and Development

Skills

Programming Languages: Abap, Ada, Assembly, C, C++, Clojure, Common Lisp, Delphi, Java, Javascript, Kotlin, Lua, Pascal, Perl, Php, Prolog, Python, R, Ruby, Scala, Shell Scripts (Bash, Zsh), Sql (Pl/Pgsql)
Frameworks/Toolkits: Akka, Apache Spark, Apache Zeppelin, Apache Flink, Apache Kafka, D3.Js, Ember.Js, Play, Ruby On Rails, Sbt, Slick
Cloud Providers: Aws, Google Cloud
Database Systems: Apache Cassandra, Cloud Bigtable, Derby, Elasticsearch, H2, Hive, Firebird, Microsoft Sql Server, Mysql, Oracle, Postgresql, Sqlite
Network Knowledge: Advanced
Server Administration: Advanced

Languages

German

Advanced

English

Advanced

Spanish

Advanced

Russian

Advanced

Education

Sep 2002 - Aug 2007

Hochschule Wismar / Universität Rostock

Diploma in Business Informatics · Business Informatics · Wismar, Germany

Statistics

Experience

Total positions 17

Experience in Information Technology 19 y

Avg length 2 y 3 m

Longest experience 14 y 2 m

Global Experience

Countries worked in 1 (Switzerland)

Primary country Switzerland

Expertise

Recent roles Remote, Project, Product Development

Main industries Information Technology, Retail, Energy

Main business areas Information Technology, Product Development, Project Management

Profile

Created

September 2023

Last Update

September 2024

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Frequently asked questions

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Jens is based in Bergen, Germany.

Jens speaks the following languages: German (Advanced), English (Advanced), Spanish (Advanced), Russian (Advanced).

Jens has at least 23 years of experience. During this time, Jens has worked in at least 8 different roles and for 15 different companies. The average length of individual experience is 1 year and 4 months. Note that Jens may not have shared all experience and actually has more experience.

Based on recent experience, Jens would be well-suited for roles such as: Remote, Project, Product Development.

In recent years, Jens has worked for Shijou GmbH, Toll Collect, Fashion Digital GmbH & Co. KG, EWE AG, and Wegtam GmbH.

Jens is most experienced in industries like Information Technology, Retail, and Energy. Jens also has some experience in Cosmetics, Professional Services, and Fashion.

Jens is most experienced in business areas like Information Technology, Product Development, and Project Management. Jens also has some experience in Business Intelligence, Quality Assurance, and Research and Development.

Jens has recently worked in industries like Information Technology, Retail, and Fashion.

Jens has recently worked in business areas like Information Technology, Product Development, and Quality Assurance.

Jens attended Hochschule Wismar / Universität Rostock for Business Informatics.

Jens is immediately available for suitable projects.

Daily Rate Distribution

0 2 4 6 8

<€800 €800-960 €960-1120 €1120-1280 €1440+

The rates shown represent the typical market range for freelancers in this position based on recent contracts on our platform.

Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.

Average rates for similar positions

Rates are based on recent contracts and do not include FRATCH margin.

1000

750

500

250

Daily rate avg. 963 €

The average daily rate is the mean of all daily rates from recent contracts of comparable freelancers on our platform.

1000

750

500

250

Median rate 860 €

The median daily rate is the middle value of all daily rates — half of comparable freelancers charge less, half charge more. Unlike the average, it is barely affected by outliers.

Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.