Senior PHP Developer (Freelance)

Location: Valencia (Preferred)

Engagement: 32-40 hours/week freelance

About the Role

We are supporting a fast-growing fintech company that is building a platform to simplify and automate business invoicing. The current team includes the CTO and one senior developer, with a roadmap to scale significantly in the coming years.

To strengthen the team, we are looking for an experienced Senior PHP Developer who can work independently, deliver new features from scratch, and help set the technical foundation for future growth. You’ll collaborate closely with the CTO on a platform built entirely in plain PHP — with strong focus on scalability, performance, and maintainability.

This freelance role offers the opportunity to join early, influence architectural decisions, and prepare the product for scale.

Key Responsibilities

• Develop new modules and extend existing features in plain PHP and MySQL.
• Ensure scalability and performance as the platform grows.
• Work closely with the CTO on technical design, priorities, and implementations.
• Document code and architecture to support maintainability and onboarding of future team members.
• Deliver clean, reusable, and well-structured code.

Must-Have Skills

• 7+ years of PHP experience, with proven ability to build applications without frameworks.
• Strong knowledge of MySQL (data modeling, joins, indexing, query optimization).
• Solid understanding of software architecture and modular code design.
• Proficiency with Git (branching, pull requests, code reviews).
• Professional communication in English (B2+).
• Ability to work independently and deliver end-to-end features.

Nice-to-Have Skills

• Experience in fintech (payments, invoicing, virtual cards).
• Awareness of security best practices.
• Familiarity with CI/CD pipelines or deployment scripting.
• Basic understanding of frontend (HTML, CSS, JavaScript).

Who You Are

• Independent: capable of owning deliverables without daily supervision.
• Collaborative: open to feedback and proactive in communication.
• Pragmatic: balancing speed with quality, knowing when “good enough” is the right choice.
• Ownership-driven: you care about the bigger picture, not just your own code.

What We Offer

• Freelance engagement with a long-term perspective.
• Join a small, agile team at an early stage with room for impact.
• Competitive freelance rate, aligned with senior experience.
• Modern workspace in Valencia with access to Outtask’s international community.