PHP is often written off as outdated, a relic of the early web. At Mollie, where PHP powers large parts of our platform, our engineers say the reality is very different.
To separate myth from reality, I spoke with two of our engineers in Lisbon, José Afonso and Francisco Veladas, who joined Mollie with strong assumptions about PHP – only to be surprised by how modern, powerful, and developer-friendly it really is.
“The PHP people picture no longer exists”
José Afonso, Application Engineer II, Merchant Experience domain (Customer IAM team)
“People usually think of frameworks like .NET Core or Spring Boot,” he says. “They associate those ecosystems with dependency injection, ORMs, clean architectures, and strong separation of concerns.”
PHP, he explains, still carries a very different mental image.
“For a lot of people, PHP means the early days of the web. Frontend and backend mixed in the same files, very little structure, very little discipline. That image is deeply ingrained, but it is also very outdated.”
José joined Mollie with experience in other object-oriented, web-focused languages. He expected a learning curve. Instead, he found something familiar.
“Modern PHP has evolved enormously. Everything people consider ‘advanced’ today has existed in PHP for years. At Mollie, we use proper architectures, strong frameworks, and modern tooling. From a technical point of view, it competes with any mainstream backend language.”
One thing that stood out immediately was developer experience.
“PHP is interpreted, which is increasingly rare. You do not wait for compilation. You change code and immediately see the result. That fast feedback loop makes a big difference in day-to-day work.”
Performance used to be the obvious counterargument, José admits. But that, too, has changed.
“With PHP 8 and JIT compilation, that trade-off is no longer what it used to be. You get speed of development without paying the same performance penalty.”
Today, José works on Single Sign-On – a product capability that directly shapes how customers access and manage their Mollie accounts. That feature lives inside his domain’s service, which is part of Mollie's PHP monorepo. It's a practical example of how PHP at scale enables teams to deliver meaningful, customer-facing functionality with confidence.
For José, the transition itself was almost unremarkable.
“The syntax is intuitive. The data types are familiar. The built-in functions are powerful. Coming from other object-oriented languages, I felt at home very quickly.”
What surprised him most was not learning PHP, but unlearning the assumptions around it.
“Working with PHP here really challenged the idea that it has fallen behind. It is still a core language of the web, and it is clearly not going anywhere.”
“I underestimated how much PHP had evolved”
Francisco Veladas, Associate Engineer, Merchant Experience domain (Identity & Security team)
Francisco Veladas’ first encounter with PHP was not especially memorable.
“My exposure to PHP before Mollie was mostly during university,” he recalls. “At the time, it felt quite limited, and I did not really see it as a language I would want to work with professionally.”
That early impression stayed with him for a while.
“When I was interviewing at Mollie, I remember telling friends that I would be working with PHP. In my head, it was a very different language from the modern stacks I was used to seeing discussed.”
Starting at Mollie quickly challenged that view.
“From day one, it became clear that this was not the PHP I remembered. We use modern versions of the language, with up-to-date tooling and practices. That alone changes the experience completely.”
Francisco now works on customer authentication and authorisation infrastructure – systems built entirely in-house that sit at the core of how Mollie's customers interact with the platform. The scale is significant: hundreds of millions of authentication and authorization checks happen every month. PHP enables the team to move quickly without sacrificing the reliability that infrastructure at that scale demands.
What surprised him most was how naturally PHP fit into building large, well-structured systems.
“It allows you to write robust, scalable code in a very clean way. The structure, the patterns, and the overall developer experience feel on par with what you would expect from any contemporary backend language.”
As he grew into the role, Francisco began to see PHP less as a legacy technology and more as a mature one.
“There is a depth to the ecosystem that I had not appreciated before. I keep discovering new capabilities, and I still feel like I am only scratching the surface.”
Looking back, his earlier assumptions now seem incomplete rather than wrong.
“PHP has been part of web development for a long time, and that experience shows. Working with it at Mollie helped me understand why it remains so widely used, and why it continues to be a strong choice for modern web products.”
Why PHP at Mollie works
PHP isn't a legacy language – it's modern, scalable, and developer-friendly. At Mollie, our PHP systems have powered the core of the platform for 20+ years, a testament to their robustness and real-world impact. Engineers benefit from fast feedback loops, clear architectures, and strong tooling, all while building large-scale products that matter.
A dedicated platform domain maintains all of our platform-specific monorepos, handling the infrastructure layer so that application engineers can focus entirely on building features. There's no need to context-switch into infrastructure concerns – that work is owned, maintained, and evolved by specialists. The result is a setup that keeps teams extremely customer-focused, without the distractions that often slow engineering organisations down.
If you're an engineer curious about PHP or looking for a platform that values craftsmanship, Mollie could be the perfect fit.