09/01/2026 updated
100 % available
Systems Programmer - C/C++ | Win32 | Go
Santiago de Compostela, Spain
Only remote
Self-taught; no formal credentials. Corporate training in security and cloud (ASAP).About me
30 years rescuing legacy systems: Clipper, Xbase++, dBase, Delphi. Lost sources recovered from binaries, DBF-to-MySQL migrations without stopping the business, DOS apps bridged to the web. Now building replacements in Go. Remote worldwide since 2000; client relationships of 18 and 25 years.
C Sharp (Programming Language)C++ (Programming Language)Code GenerationDBasePostgreSQLMySQLXBaseXbase++
C/C++ and Win32 Systems Programming
Over two decades of deep C/C++ and Win32 systems programming, including FFI, callbacks, runtime code generation, driver injection, cryptography, printing, serial I/O, and IPC. Author of ot4xb, a C/C++ FFI and Win32 interop library redistributed inside four commercial third-party libraries, running in banks, hospitals, clinics, courts, schools, and a metro ticketing system.
Go Development
Primary language for all new projects since early 2025.
x86 Assembly and Reverse Engineering
Author of a one-pass runtime x86 assembler inside ot4xb generating callback thunks and managing stack layout at runtime. Hundreds of hours disassembling code with IDA (Free) and walking through Wine sources. Performed lost-source reconstruction by disassembling compiled .obj files and rewriting them in C.
Database Integration (DBF/CDX, ADS, MySQL, SQLite, SQL Server, PostgreSQL)
Native C/COM-level access to multiple database engines. Author of mysql4xb, a C++ component wrapping libmysql for Xbase++. Deep day-to-day MySQL use including full company migration from DBF to MySQL. SQLite wrappers dating back to 2009, deployed in 25,000 UK schools. ADO/COM wrapper for SQL Server and a PostgreSQL wrapper used by other developers.
JavaScript (Vanilla, No Frameworks)
Writing custom JavaScript frameworks since 2001 with no third-party dependencies. Projects include browser-based recreations of DOS UI patterns, JSON-driven control injection for financial institution order applications, attribute-directed HTML fragment engines, and closure-ui custom elements providing desktop-GUI behavior in the browser.
xBase Family (Xbase++, Clipper 5, Harbour, dBase III+)
26 years of Xbase++ experience, including deep knowledge of its internals, file formats, and runtime. Author of ot4xb, the primary C++ bridge library for the Xbase++ ecosystem. Also experienced with Clipper 5, dBase III+, and Harbour, including bridging these environments to Go and modern systems.
Web Backends (PHP, C#, Xbase++/WAA, CGI)
Built internal web applications using Xbase++/WAA, PHP (Concrete5-based microsites and standalone projects, 2012-2020), C# IIS gateways, and CGI-based backends. Designed JSON-only backend architectures that outlived full backend rewrites in other languages.
Email and MIME
Intensive work with RFC822/MIME in an internal mail-management system binding company correspondence to orders, including quarantining original .rfc822 files for reference.
AI-Assisted Development
Daily hands-on AI-assisted development since 2024. Claude Code fully integrated into the development environment end to end. Experience with ChatGPT and Codex. Builds tooling for AI agents, including mkskill for generating agent-ready AGENTS.md and SKILL.md documentation from a single source.
Experience
Professional experience10+ years
Freelancer since1996
Languages
EnglishFluentSpanishNative speaker
Project history
Migrating three Delphi applications to Go for the same client served in 2000-2004, a 25-year client relationship. One of them is the employee clock system first written in Clipper/DOS around 2000, later rewritten in Delphi, now being rewritten in Go.
Around 30 direct clients in 10+ countries, most found through community forums. Bulk of engagements were C++ systems layer work beneath Xbase++ applications. Selected clients include EDM2000 (UK) for a neonatal nutrition application used in UK and Irish hospitals, Groenestein Beheersoftware (NL), LaserPlus (DE/US), TRANSAX (CA), CT-PEN (AT), PSIC/Lusorol (PT), AOKI Sistemas (BR), Softsupply Informatica Ltda (BR), MRTIENDA (MX), JD Software (NL).
Eighteen years with the same client, from first quote to the orderly shutdown of their legacy system. Full-time long-term contractor, de facto employee (daily reports from January 2012). Three weeks on-site in Montreal (May-June 2022). Team of 5 developers (later 2): weekly scrum, mandatory code review, Bitbucket + Crucible + Bamboo CI, later GitLab, Wrike (2013-2022). Work included order-synchronization programs, outgoing email queues, fax and voicemail management, WAV to MP3 conversion (SoX/LAME, 2009). Decommissioning phase: PCL to PDF printing, Elavon/Converge payments, purplship shipping, cloud migration, DBF to MySQL, OWASP Top 10 (2021) security review.