Project Posting: Senior C++ Legacy Developer for Oracle OSCAR Point of Sale System

Project overview

For a point-of-sale system used internationally, we are looking for a highly experienced freelancer with proven expertise in C++, legacy systems, and the technical takeover of historically grown applications.

The point-of-sale system is based on Oracle OSCAR and is currently operated productively in several European countries. It is a business-critical application with a long history and an established customer base. Strategic further development is not currently planned. The focus is on stability, operational security, knowledge retention, and the ability to analyze errors and make necessary adjustments.

To ensure operational continuity, an external specialist is sought to technically take over the existing solution, understand the development and build environment, and serve as a competent point of contact for analysis, troubleshooting, and hotfix development in the medium term.

The existing point-of-sale system will be decommissioned at the end of 2028. Support must be ensured until then.

Important: In case of acute need, support must begin immediately!

Responsibilities

Technical Familiarization and Knowledge Transfer

Error Analysis and Hotfixes

Regulatory Adjustments

Documentation

Technological Environment

Must-Have Requirements

• Familiarization with an extensive C++ codebase
• Transfer of knowledge from existing developer documentation and workshops
• Analysis of system architecture, modules, and dependencies
• Understanding of database and configuration logic
• Documentation of relevant findings and operational procedures
• Analysis of disruptions in productive systems
• Root cause analysis in C++ code, database, configuration, and scripts
• Development of low-risk hotfixes
• Creation and testing of cumulative patch packages
• Support for rollback and recovery scenarios
• Implementation of mandatory legal or regulatory changes
• Analysis of possible impacts on existing functions and interfaces
• Testing and documentation of adjustments
• Structuring and supplementing technical documentation
• Documentation of build processes, system specifics, and error patterns
• Ensuring sustainable knowledge retention within the organization
• C++
• Oracle OSCAR POS
• Oracle database environment
• Microsoft Visual Studio .NET 2003 (VC7)
• Windows-based build environment
• Batch scripts and command-line builds
• makall Build Process
• FGL components
• Windows DLLs and Libraries
• Single and multiuser environments
• Patch and release management
• At least 10 years of practical experience in C++ development
• Demonstrable experience with the maintenance and takeover of legacy systems
• Very good knowledge of older Microsoft C++ toolchains (VC6, VC7, Visual Studio .NET 2003 or similar)
• Experience with Windows-native development, DLLs, compiler and linker configurations
• Profound knowledge of build processes, batch scripts, and make systems
• Strong skills in debugging, troubleshooting, and root cause analysis
• Experience with database-supported enterprise applications
• Ability for independent familiarization with large and sometimes insufficiently documented codebases
• Very good German language skills, both written and spoken

Nice to have

Framework Conditions

• Experience with POS, cash register, retail, or ERP systems
• Oracle database knowledge
• Experience with FGL or 4GL technologies
• Knowledge of historical Windows development environments
• Experience with POS peripherals (scanners, receipt printers, payment services, etc.)
• Experience with hotfix, patch, and release management
• Experience in knowledge transfer from long-term system developers

Project details

from December 2026

until the end of 2028

initially intensive for familiarization, later on-call as needed

Language: German

Contract Type: Freelancer / Independent Consultant

Financial Framework Conditions: On an hourly rate basis according to effort plus a monthly "retainer" fee

• Start: 2026-12
• Duration: 24 Monate
• Remote: remote
• Location: Mannheim, Deutschland, DE
• Languages: German