Sergej Tissen - Senior IT Consultant

Q: Where is Sergej based?

Sergej is based in Selva, Spain and can operate in on-site , hybrid , and remote work models.

Q: What languages does Sergej speak?

Sergej speaks the following languages: German (Native), English (Advanced), Russian (Intermediate) .

Q: How many years of experience does Sergej have?

Sergej has at least 18 years of experience. During this time, Sergej has worked in at least 5 different roles and for 7 different companies . The average length of individual experience is 2 years and 3 months . Note that Sergej may not have shared all experience and actually has more experience.

Q: What is Sergej's latest experience?

Sergej's most recent position is Senior IT Consultant at Freelance .

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

In recent years, Sergej has worked for Freelance and codecentric AG .

Q: Which industries is Sergej most experienced in?

Sergej is most experienced in industries like Information Technology (IT) , Professional Services , and Healthcare . Sergej also has some experience in Tourism and Hospitality , Construction , and Education .

Q: Which business areas is Sergej most experienced in?

Sergej is most experienced in business areas like Information Technology (IT) , Product Development , and Project Management .

Q: Which industries has Sergej worked in recently?

Sergej has recently worked in industries like Information Technology (IT) and Professional Services .

Q: Which business areas has Sergej worked in recently?

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

Recommended expert

Selva, Spain

Experience

Jan 2023 - Present

3 years 2 months

Munich, Germany

Senior IT Consultant

Freelance

Oct 2017 - Dec 2022

5 years 3 months

Munich, Germany

Senior IT Consultant

codecentric AG

Architecture and development of a serverless-based platform, built serverless AWS infrastructure, continuous deployment pipelines, and implemented business logic. (React, TypeScript, JavaScript, Node.js, AWS, Java, Kotlin, GraphQL)
Conceived and developed a service to implement requirements from the Digital Supply Act. (Java, Spring Boot, AWS, Kubernetes)
Advised on architecture and developed a microservices platform for internal business applications. (React, TypeScript, AWS, Java, Spring Boot, Kubernetes)

Jan 2016 - Sep 2017

1 year 9 months

Munich, Germany

Senior Fullstack Developer

Jochen Schweizer GmbH

Migrated and enhanced the e-commerce platform in AWS, set up AWS infrastructure for microservices, continuous deployment pipelines, and designed and implemented microservices.
Provided organizational and technical mentoring to apprentices.
Technologies: React, TypeScript, JavaScript, Node.js, AWS, Docker

May 2014 - Nov 2015

1 year 7 months

Munich, Germany

Scrum Master

Allplan GmbH

Led teams developing an online project management portal and a CAD application, introduced and scaled Scrum processes to 16 teams.
Trained and coached on continuous integration adoption.
Provided organizational and technical mentoring to apprentices.
Approaches: Scrum, Kanban, DevOps

Apr 2013 - Apr 2014

1 year 1 month

Berlin, Germany

Technical Project Manager

Aperto AG

Migrated existing web portals to an enterprise web CMS, coordinated a development team, technical conception and led client workshops.
Created and monitored project plans, cost estimation, and proposals.
Technologies: Magnolia CMS (Java), JavaScript

Aug 2010 - Jun 2012

1 year 11 months

Berlin, Germany

Fullstack Developer

Freelance

Developed online registration portals for medical conferences. (Java, Groovy, JavaScript)

Oct 2008 - Jul 2010

1 year 10 months

Berlin, Germany

Fullstack Developer

Lambdalogic GmbH

Developed online registration portals for medical conferences, backend and frontend development, release management, and designed and implemented a generic form editor. (Java, Groovy, JavaScript)

Mar 2007 - Aug 2008

1 year 6 months

Berlin, Germany

Fullstack Developer

Alpha-Spirit

Developed an online e-learning platform for video-based courses. (Java, JavaScript)

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 Information Technology (11 years), Professional Services (8.5 years), Healthcare (3.5 years), Tourism (1.5 years), Construction (1.5 years), and Education (1.5 years).

Information Technology

Professional Services

Healthcare

Tourism

Construction

Education

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 (18 years), Product Development (8.5 years), and Project Management (2.5 years).

Information Technology

Product Development

Project Management

Summary

Fullstack Developer with 15+ years of experience in software development. Specializing in using React, Next.js, and Java to build efficient and scalable web applications. As a certified AWS Solutions Architect and AWS Developer, I have years of experience implementing cloud-native architectures on AWS. I bring a strong foundation in DevOps practices, utilizing tools such as GitLab and AWS CDK, to create resilient and evolvable solutions.

I am a 🇩🇪 German national, currently freelancing from 🇪🇸 Spain.

Skills

Development

React
Typescript
Javascript
Node.js
Graphql
Next.js
Java
Spring Boot

OPS

Ci/cd
Docker
Kubernetes
Gitlab
Akamai
Infrastructure As Code

AWS

Vpc
Ecs
Lambda
S3
Dynamodb
Kinesis
Route53
Codepipeline

Architecture

Serverless
Microservices
Cloud-native
Event-driven
Rest Api Design

Approaches

Scrum
Kanban
Devops
Lean
Safe

Languages

German

Native

English

Advanced

Russian

Intermediate

Education

Oct 2010 - Mar 2013

IPU Berlin

Bachelor of Arts in Psychology · Psychology · Berlin, Germany · 1.4

Oct 2001 - Jun 2005

University of Paderborn

Bachelor of Computer Science · Computer Science · Paderborn, Germany · 1.6

Certifications & licenses

AWS Certified Developer - Associate Level

AWS Certified Solutions Architect - Associate Level

IHK Certified Trainer (Trainer Certificate)

Intensive General English Course (6 months in Sydney)

ScrumMaster Advanced

Profile

Created

November 2022

Last Update

January 2026

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Frequently asked questions

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

Where is Sergej based?

Sergej is based in Selva, Spain and can operate in on-site, hybrid, and remote work models.

What languages does Sergej speak?

Sergej speaks the following languages: German (Native), English (Advanced), Russian (Intermediate).

How many years of experience does Sergej have?

Sergej has at least 18 years of experience. During this time, Sergej has worked in at least 5 different roles and for 7 different companies. The average length of individual experience is 2 years and 3 months. Note that Sergej may not have shared all experience and actually has more experience.

What roles would Sergej be best suited for?

Based on recent experience, Sergej would be well-suited for roles such as: Senior IT Consultant, Senior Fullstack Developer, Scrum Master.

What is Sergej's latest experience?

Sergej's most recent position is Senior IT Consultant at Freelance.

What companies has Sergej worked for in recent years?

In recent years, Sergej has worked for Freelance and codecentric AG.

Which industries is Sergej most experienced in?

Sergej is most experienced in industries like Information Technology (IT), Professional Services, and Healthcare. Sergej also has some experience in Tourism and Hospitality, Construction, and Education.

Which business areas is Sergej most experienced in?

Sergej is most experienced in business areas like Information Technology (IT), Product Development, and Project Management.

Which industries has Sergej worked in recently?

Sergej has recently worked in industries like Information Technology (IT) and Professional Services.

Which business areas has Sergej worked in recently?

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

What is Sergej's education?

Sergej holds a Bachelor in Psychology from IPU Berlin and a Bachelor in Computer Science from University of Paderborn.

Does Sergej have any certificates?

Sergej has 5 certificates. Among them, these include: AWS Certified Developer - Associate Level, AWS Certified Solutions Architect - Associate Level, and IHK Certified Trainer (Trainer Certificate).

What is the availability of Sergej?

Sergej is immediately available full-time for suitable projects.

What is the rate of Sergej?

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