Back-End Engineer (PHP)

About us:

iO Software Solutions is a product and engineering hub based in Plovdiv, Bulgaria. Our work spans the full SaaS product lifecycle — from product management and software development to quality assurance, customer support, and customer success. We operate in an international environment, with team members based in Bulgaria, Indonesia, and Kosovo, collaborating closely with our client teams in Austria.

In this role, you’ll contribute to the development of the Invitario platform — an established B2B SaaS solution for managing live, virtual, and hybrid events. Used by enterprise and SME customers across the DACH region, Invitario supports invitations, registrations, participant communication, integrations, and event workflows throughout the whole event lifecycle.

Your Role:

We’re looking for a Back-End PHP Engineer to join our Dev team and contribute to the ongoing development and improvement of the Invitario platform. This is a hands-on engineering role combining new feature development, backend improvements, and the continuous evolution of an established SaaS product. You’ll work with an existing codebase where understanding the bigger picture, making thoughtful technical decisions, and improving code quality are just as important as writing new code.

We’re looking for someone who enjoys understanding how systems work, identifying opportunities for meaningful improvements, and finding practical solutions to real engineering challenges.

You’ll collaborate closely with Backend, Frontend, Product, QA, and Customer Success team members, contributing to technical discussions and helping build a reliable, maintainable platform over time.

Key Responsibilities:

• Design, build, test, and maintain backend services, APIs, and business logic.
• Improve existing backend systems with a focus on reliability, performance, and maintainability.
• Work with databases, data models, migrations, and SQL queries.
• Investigate and resolve bugs, technical issues, and production-related problems.
• Support integrations with internal platform components and external systems.
• Write automated tests and participate in code reviews.
• Collaborate actively with Product, Frontend, QA, and Customer Success teams.

What we’re looking for:

• 3–5 years of professional experience in backend development with PHP.
• Strong working knowledge of PHP 8 (hands-on experience with Symfony and/or Laravel)
• Solid understanding of SQL and relational databases, ideally PostgreSQL.
• Experience designing, building, and maintaining REST APIs.
• Experience writing unit tests, preferably using PHPUnit.
• Strong debugging, analytical, and problem-solving skills.
• A practical approach to code quality, refactoring, and maintainability.
• Ability to work independently, take ownership, and communicate proactively.
• A product-oriented mindset and an interest in understanding the business context behind technical decisions.
• Fluent English, both written and spoken.

Nice to have:

• Experience with Docker-based development workflows.
• Familiarity with TypeScript.
• Understanding of jQuery or legacy frontend components.
• Knowledge of AWS or cloud-based infrastructure.
• Experience working with external integrations and third-party APIs.

What you can expect:

Long-term product involvement: Work on an established B2B SaaS platform rather than moving between short-term client projects.

Meaningful engineering contribution: Take part in technical discussions, improve existing systems, and contribute to the long-term evolution of a profitable product.

Hybrid working & flexibility: Enjoy a hybrid working setup with flexible working hours.

Professional development: Access support for relevant training, certifications, and continuous learning opportunities.

Equipment: Get the hardware and tools you need to perform at your best.

Team events & retreats: Enjoy unique team retreats in Austria and regular team events throughout the year.

Performance & salary reviews: Benefit from a structured performance management process, with regular feedback, development discussions, and salary reviews.

If this sounds like a good fit, we’d be happy to receive your CV in English. Please note that only shortlisted candidates will be contacted regarding the next steps.