Cristian Serje Reyes - Team Lead Mobile Native Apps

Q: Where is Cristian based?

Cristian is based in Munich, Germany .

Q: What languages does Cristian speak?

Cristian speaks the following languages: Spanish (Native), German (Advanced), English (Advanced), Portuguese (Advanced), Italian (Intermediate) .

Q: How many years of experience does Cristian have?

Cristian has at least 19 years of experience. During this time, Cristian has worked in at least 7 different roles and for 6 different companies . The average length of individual experience is 3 years and 8 months . Note that Cristian may not have shared all experience and actually has more experience.

Q: What is Cristian's latest experience?

Cristian's most recent position is Team Lead Mobile Native Apps at Check24 GmbH .

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

In recent years, Cristian has worked for Check24 GmbH .

Q: Which industries is Cristian most experienced in?

Cristian is most experienced in industries like Information Technology (IT) , Banking and Finance , and Telecommunication . Cristian also has some experience in Tourism and Hospitality .

Q: Which business areas is Cristian most experienced in?

Cristian is most experienced in business areas like Information Technology (IT) , Product Development , and Customer Service .

Q: Which industries has Cristian worked in recently?

Cristian has recently worked in industries like Banking and Finance and Information Technology (IT) .

Q: Which business areas has Cristian worked in recently?

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

Recommended expert

Munich, Germany

Experience

Apr 2019 - Present

6 years 11 months

Munich, Germany

Team Lead Mobile Native Apps

Check24 GmbH

Built and managed a high-performing native app team (Android & iOS) from scratch
Modernized the finance application with new features, leveraging Kotlin, Java, and Spring Boot microservices
Introduced and scaled backend services enabling secure, high-traffic financial transactions for millions of users
Improved development efficiency with custom tools for crash reporting, CI/CD pipelines, and release management
Led recruitment, coaching, and mentoring of developers, fostering professional growth and cross-functional collaboration

Aug 2016 - May 2019

2 years 10 months

Munich, Germany

Senior Mobile Engineer

Check24 GmbH

Designed and developed a new Android finance application from scratch
Architected and implemented backend microservices (Java, Spring, REST APIs) powering both iOS & Android apps
Built reusable frameworks to accelerate app development across Check24
Scaled systems to support 5M+ active users securely and reliably

Nov 2011 - Aug 2016

4 years 10 months

Munich, Germany

Senior Software Engineer

Insparx GmbH

Delivered Android features and backend solutions using Java (EJB, JMS) and Python GAE
Designed backend messaging and notification systems with NoSQL and search integrations
Integrated payment providers and external APIs into backend clusters running on JBoss

Mar 2010 - Oct 2011

1 year 8 months

Lisbon, Portugal

Java and Software Senior Developer

TMN - Portugal Telecom Information Systems

Developed business applications in one of the largest Portuguese companies in technology, communication, and information systems, working on different teams with innovative and challenging projects
Designed and implemented the architecture of several projects such as the EasyMessaging system for SMS and MMS, providing services via web for public portals and external systems via SOAP and CGI, and led design and development of projects for internal and external company use using diverse technologies and frameworks

Oct 2008 - Oct 2009

1 year 1 month

Medellín, Colombia

IT Coordinator/Senior Developer

DownUnderGroup SA

Headed the information system area, coordinating IT affairs in the hotel chain and developing applications in C++ and Java
Updated and developed websites, client database, and bookkeeping systems
Checked the work of local and other branch teams
Coordinated a four-person team to maintain different systems
Performed data integrity checks and site modifications using CMS

Jun 2007 - Jul 2008

1 year 2 months

Maringá, Brazil

Software Architect and Developer, Team Leader

SG Sistemas

Developed and led software projects for automation of companies, working with PDAs, web development, and software development
Designed and developed mobile applications with wireless updates compatible with Brazilian mobile networks (Android, iPhone, Symbian, Palm, Blackberry)
Built web applications to check partner information through the database of a Brazilian market chain using SQLServer, MySQL, Tomcat, ActionScript, XML, and Struts
Developed an in-house remote administration app to manage employees remotely using Java, C++ Builder, HTML, and sockets

Oct 2006 - May 2007

8 months

Barranquilla, Colombia

Programmer, Consultant

Sigma

Developed applications specified by customers using Java and C++
Worked on different projects and programming languages
Provided customer technical support
Developed web applications in JSP and reports using iReport

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 (13.5 years), Banking and Finance (9.5 years), Telecommunication (1.5 years), and Tourism (1 year).

Information Technology

Banking and Finance

Telecommunication

Tourism

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 (18.5 years), Product Development (16 years), and Customer Service (0.5 years).

Information Technology

Product Development

Customer Service

Summary

Engineering Team Lead with 15+ years of experience building mobile applications and scalable backend systems used by millions of users across Europe and Latin America. Proven expertise in Native Android development, Java, Backend, Microservices, Cloud and skilled in leading and mentoring cross-functional teams, delivering high-performance solutions, and driving innovation in fintech, telecom, and large-scale consumer platforms.

Skills

Communication And Interpersonal Skills
Backend: Java, Spring Boot, Rest Apis, Microservices, Jms, Ejb, Jboss, Python Gae, C++
Mobile: Android (Kotlin, Java), Ios, Flutter, Hybrid Apps
Cloud & Devops: Aws, Gcp, Docker, Kubernetes, Ci/cd
Databases: Sql (Mysql, Postgresql, Sql Server), Nosql (Mongodb, Redis, Elasticsearch, Solr)
Leadership: Team Building, Mentoring, Agile Methodologies, Cross-functional Collaboration

Languages

Spanish

Native

German

Advanced

English

Advanced

Portuguese

Advanced

Italian

Intermediate

Education

Jan 2003 - Mar 2007

University of the North

Computer Science Engineer · Computer Science · Barranquilla, Colombia

Profile

Created

November 2025

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Frequently asked questions

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

Where is Cristian based?

Cristian is based in Munich, Germany.

What languages does Cristian speak?

Cristian speaks the following languages: Spanish (Native), German (Advanced), English (Advanced), Portuguese (Advanced), Italian (Intermediate).

How many years of experience does Cristian have?

Cristian has at least 19 years of experience. During this time, Cristian has worked in at least 7 different roles and for 6 different companies. The average length of individual experience is 3 years and 8 months. Note that Cristian may not have shared all experience and actually has more experience.

What roles would Cristian be best suited for?

Based on recent experience, Cristian would be well-suited for roles such as: Team Lead Mobile Native Apps, Senior Mobile Engineer, Senior Software Engineer.

What is Cristian's latest experience?

Cristian's most recent position is Team Lead Mobile Native Apps at Check24 GmbH.

What companies has Cristian worked for in recent years?

In recent years, Cristian has worked for Check24 GmbH.

Which industries is Cristian most experienced in?

Cristian is most experienced in industries like Information Technology (IT), Banking and Finance, and Telecommunication. Cristian also has some experience in Tourism and Hospitality.

Which business areas is Cristian most experienced in?

Cristian is most experienced in business areas like Information Technology (IT), Product Development, and Customer Service.

Which industries has Cristian worked in recently?

Cristian has recently worked in industries like Banking and Finance and Information Technology (IT).

Which business areas has Cristian worked in recently?

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

What is Cristian's education?

Cristian attended University of the North for Computer Science.

What is the availability of Cristian?

Cristian is immediately available full-time for suitable projects.

What is the rate of Cristian?

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