Timon R.
embedded linux, Java, Backend, BSI Standards
Experience
Administrator
Various Clients
- Setup and maintenance of multiple web servers.
- Configuration of load balancing to distribute traffic across multiple servers.
- Implementation of HTTPS with Let's Encrypt certificates for secure data transmission.
- Setup of automated backups and recovery strategies.
- Optimization of server performance through caching (e.g., Redis, Memcached).
- Security measures like SSH hardening, fail2ban, and regular security audits.
- Tools: Nginx / Caddy as web and proxy servers, Docker for application containerization, monitoring with Grafana.
Administrator
Various Clients
- Building a wired and a Wi-Fi network based on TP-Link Omada.
- Planning and implementing a redundant network architecture to ensure high availability.
- Setting up a Wi-Fi mesh network for seamless handover between wireless repeaters.
- Configuring VLANs to separate different network segments (e.g., employees, guests, IoT devices).
- Implementing QoS rules to prioritize critical applications (e.g., VoIP, video conferences).
- Tools: Raspberry Pi with Ubuntu Server, TP-Link Omada Controller interface, routers, Wi-Fi devices, VLAN configuration via CLI/WEB interface, Wireshark for network analysis.
Backend Developer – Data Exchange Platform
Insurance Group
Generation of a KVNR: Service for creating and securely storing health insurance numbers for insurance customers.
Development of a RESTful API for creating and managing KVNRs.
Implementation of secure storage and transmission of KVNR data in compliance with data protection regulations (e.g., GDPR).
Implementation of efficient validation and error handling to ensure the correctness of generated numbers.
Integration of a logging mechanism to track system operations and ensure auditability.
Creating an integration service: integrating various internal and external services into a unified data solution for data usage and processing.
Designing and implementing a microservice architecture approach to integrate different data sources.
Developing an API gateway solution with Spring Boot to manage communication between internal and external services.
Implementing mechanisms to synchronize and harmonize data from different systems to provide a consistent data view.
Implementing an error handling and retry system to improve the reliability of the integration service.
Implementing a deletion concept for personal data in compliance with data protection regulations (e.g., GDPR).
Tools: Java + Spring Boot, Maven, IntelliJ, Postman, OpenAPI / Swagger, PostgreSQL, OPNsense.
Administrator
Various Clients
- Building a smart home.
- Integrating various devices (e.g., lights, heating, security systems) into a seamless ZigBee mesh network.
- Implementing automation rules (e.g., turning on lights when motion is detected, adjusting heating based on weather data).
- Ensuring data integrity and security through encrypted communication between devices.
- Optimizing energy consumption analysis and control through smart device integration.
- Tools: Linux Raspberry Pi OS, Raspberry Pi as local server infrastructure, Home Assistant as the central platform, Zigbee for wireless device communication, MQTT broker for uninterrupted mesh communication.
Pen Tester Training
- Planning and Scoping
- Information Gathering and Vulnerability Identification
- Attacks and Exploits
- Reporting and Communication
- Tools and Code Analysis
Backend Developer – Event Software
Software solution for accrediting meeting attendees
- Defining interfaces and documenting them with Swagger/OpenAPI for an API-first approach.
- Designing the backend architecture and implementing it.
- Testing and deploying the solution to the cloud.
- Tools: Java/Spring Boot (microservices), Swagger, MinIO, MariaDB, GitHub including build pipelines, Kubernetes.
Backend Developer – Whistleblower Protection Software
lettly.de
- Developing SaaS solutions for various end clients.
- Implementing cryptographic methods, including according to BSI standard TR 02102-1.
- Implementing security and access control concepts in backend systems.
- Implementing a reporting office according to the requirements of the Whistleblower Protection Act (HinSchG).
- Integrating Stripe as a payment provider.
- Tools: Java/Spring Boot (microservices), Swagger, MongoDB, MinIO, MariaDB, GitHub including build pipelines, Kubernetes, Linux.
Backend Developer – Voting Software
ballotly.de
- Developing SaaS solutions for various end clients.
- Implementing cryptographic methods, including those based on BSI standard TR 02102-1 and Common Criteria (CC).
- Implementing business logic according to election regulations.
- Creating a synchronization concept for a distributed architecture.
- Tools: Java/Spring Boot (microservices), Swagger/OpenAPI, Redis, SSE, DDA, MinIO, MariaDB, GitHub including build pipelines, Kubernetes, Linux.
Part-time project
Automotive supplier
- Creating shipping labels. Batch labels are printed on an industrial printer, including outer packaging labels.
- Designing a server-client software architecture for scalability across multiple workstations.
- Developing interfaces to control industrial Zebra label printers.
- Designing and implementing bidirectional data synchronization between the labeling system and the MS SQL database.
- Supporting and maintaining the software.
- Tools: IntelliJ, Java + JavaFX, MS SQL, Linux (Raspberry Pi OS), Raspberry Pi.
Fullstack Developer – Plant Monitoring
Machine and plant engineering
- Enhancing the new platform to support production in a distributed machine landscape.
- Developing and deploying solutions according to machine generations.
- Providing technology consulting for new installations.
- Tools: software architecture (EDA, DDD), Java/Spring Boot, MinIO, MySQL, MongoDB, MQTT, mail proxy & bridges, C#.
Backend Developer - Documentation Tool
In-house development / Various clients
- Service app as a documentation and reference tool for machines, projects, real estate & facility management.
- Template-based process documentation for consistent quality.
- Tools: Java/Spring Boot (Microservices), NodeJS, MongoDB, MinIO, MariaDB, GitLab, Docker & Docker Compose on Linux servers.
App Developer - Quality Assurance
Road Construction and Maintenance
- Networked app for quality control in road and asphalt construction.
- Design and implementation of the infrastructure and the Android app.
- Mathematical modeling of the business logic.
- Tools: Java, Android, BLE, SQLite, GitLab, Confluence.
Fullstack Developer - Process Management
Agriculture and Forestry
- Further development of an in-house platform for process optimization and management in agricultural operations.
- Technology consulting.
- Tools: Software architecture (EDA; DDD), Java 8, Angular, NodeJS, Apache Cassandra, MariaDB.
Vocational training in application development
b.i.b. International College Bielefeld
Focus on fullstack and app development
Summary
Added value in digitalization and software development - from the first idea to the final solution. "I enjoy working with my clients to find the right solutions!" On the web, I'm at home in the backend - interfaces are my strength.
Languages
Education
B.I.B. International College Bielefeld
Vocational training in application development, focusing on full-stack and app development · Application Development · Bielefeld, Germany
Certifications & licenses
Pen-Tester
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