Backend Engineer — PHP / CodeIgniter

About The Role We are looking for a Mid–Senior Backend Engineer with strong PHP experience to develop, maintain, and improve backend services, APIs, and production-critical systems. CodeIgniter is our primary production framework — including legacy versions — and will be the core of your day-to-day work. Some projects may involve Laravel, so familiarity with the framework at a comfortable level would be valuable. You will work hands-on across established production environments, contributing to API development, performance improvements, debugging, reliability, and technical modernization. This is a full-stack-leaning role: approximately 80% of the work is back-end and full-stack development, with about 20% involving front-end responsibilities. The ideal candidate has solid foundational front-end experience with HTML, CSS, JavaScript, Bootstrap, and Vue.js, and is comfortable stepping into front-end work when needed — particularly across back-office applications, CRUD systems, internal dashboards, administrative interfaces, and other business-facing tools — without needing to be a dedicated front-end specialist. The position also includes backup support responsibilities for core backend systems. Key Responsibilities Develop, maintain, and improve backend services and REST APIs.Work confidently within existing and legacy PHP codebases, including maintaining, extending, and refactoring functionality.Design, build, and integrate internal and external APIs.Investigate, debug, and resolve production issues.Profile applications and improve backend performance, reliability, and scalability.Improve test coverage and system reliability, especially around business-critical workflows.Work day to day with relational databases, caching layers, and queue-based systems.Provide backup support for core backend systems when required.Participate in code reviews and contribute to engineering best practices.Document technical decisions, share knowledge, and collaborate closely with a small technical team.Use AI coding agents and modern development tools responsibly as part of the development workflow.Step into front-end work when needed, maintaining, troubleshooting, and enhancing both modern and legacy front-end code across back-office applications, CRUD systems, internal dashboards, and administrative interfaces. Required Skills And Experience 5+ years of professional backend development experience with PHP.Strong hands-on experience with CodeIgniter, including legacy and older production versions — our primary and most important framework.Familiarity with Laravel at a comfortable level is valuable, as some projects may involve working within it.Solid understanding of REST API design, implementation, and integration.Good working knowledge of MySQL, including schema design, query optimization, and performance troubleshooting.Experience with Redis for caching, queues, or related backend use cases.Solid foundational front-end experience with HTML, CSS, JavaScript, Bootstrap, and Vue.js.Familiarity with legacy jQuery, as some existing systems still rely on it.Comfortable owning production systems, including debugging, profiling, incident investigation, and safe incremental refactoring.Experience using Git-based workflows.Exposure to AWS infrastructure and CI/CD pipelines. Technical Stack Languages PHP 7.x–8.x Frameworks CodeIgniter (including legacy versions), Laravel Databases and Data Tools MySQL, Redis Search and Analytics Elasticsearch is a plus Infrastructure and Tooling AWS, GitHub, CI/CD pipelines Front-End HTML, CSS, JavaScript, Bootstrap, Vue.js, legacy jQuery Development Tools AI-assisted coding tools such as Claude Code, Cursor, Copilot, or similar Preferred Qualifications Beneficial but not required: Experience modernizing, migrating, or refactoring legacy systems.Experience introducing automated tests into previously untested codebases.Experience with Elasticsearch tuning, message queues, BigQuery, or ETL workflows.Previous experience in the travel or travel-tech industry. Candidate Profile We Are Looking For Someone Who Is Pragmatic and delivery-focused, with a strong ability to ship safe, incremental improvements.Highly reliable and comfortable taking ownership of production-critical backend systems.Confident working with legacy code, ambiguity, and evolving technical environments.Focused on improving systems rather than rewriting them unnecessarily.A clear communicator who collaborates well in a small team environment.Quality-minded, with an interest in improving tests, observability, documentation, and engineering practices.Curious about modern development workflows, including responsible use of AI coding tools.Comfortable stepping into front-end work when needed, without needing to be a dedicated front-end specialist. What Success Looks Like In this role, success means becoming a trusted owner of important backend systems, delivering reliable improvements to existing services, contributing to API and infrastructure stability, and helping the team modernize systems in a practical and sustainable way. You will be expected to balance delivery speed with production safety, communicate clearly, and make thoughtful technical decisions that improve reliability, maintainability, and long-term system health. Send your CV and a short note about your background to contact@undercode.ro Subject line: Backend Engineer — PHP / CodeIgniter apply for this role