Senior Software Engineer (PHP)

Want to know how a leading workplace experience and facility management company is powered by technology?

At ISS Tech Team, we create smarter workplace experiences through technology. Our Global Technology Solutions team builds digital solutions, from sensors and IoT devices to data, analytics and AI-driven capabilities, that support our ISS A/S operations across Cleaning, Workplace, Food and Technical Services.

With tech hubs in Copenhagen, Warsaw, and Porto, and teams collaborating across more than 30 countries, our ISS Tech team develops our digital solutions that have a real impact on both our customers and our people.

Location: Porto, Portugal

Work regime: Hybrid

The Job Role as Senior Software Engineer (PHP):

We build the platform people use to order and pay for food and services at work. It sounds simple. It is not. Behind it are three apps, a PHP backend that moves real money in real time, native integrations with payment terminals, printers, scales and scanners, and a long list of payment, identity and workplace systems that all have to agree with each other. Every receipt has to be right, in every country, under every local fiscal rule. And it runs in production for some of the largest organisations in the world, so when you ship something, people use it the same day.

We are also changing how we build software. Specs come first. AI coding assistants and agents are part of everyday work, not a side experiment. We care about moving fast and we care just as much about not breaking things, and we are still learning how to do both at once. One thing we are sure of: the fundamentals matter more now, not less. Clean code, good design, clear domain boundaries and solid tests are what separate an AI-assisted team that ships from one that just produces code. If that sounds like the kind of problem you want to be part of, keep reading.

As a Senior Full Stack Developer you will be one of the people the team in Porto looks to when things get hard. You will own features end to end, make the architecture calls on the apps, the backend and the integrations, and take on the thorniest problems around payments, authentication, devices and performance. You will review a lot of code, mentor the people around you, and have a real say in what AI-native, spec-driven engineering looks like here and across our hubs in Copenhagen and Warsaw.

What you’ll do:

• Start from the spec. We write down what we are building before we build it, and you will help turn product ideas into clear specs and acceptance criteria that product, QA and your AI tools can all work from.
• Build with AI as a normal part of your day. Coding assistants and agents help us move faster on implementation, tests, refactoring and docs, and you own the result as if you had typed every line yourself.
• Help us get better at this. Context files, prompt and spec libraries, automated reviews, the guardrails that keep us fast without getting sloppy. We are figuring it out together and your ideas count.
• Keep the fundamentals strong. AI does not replace good engineering, it amplifies it. Clean code, design patterns, domain-driven design, SOLID, sensible boundaries and tests you can trust are what make the AI output worth shipping.
• Work on our Angular and Ionic apps (TypeScript, RxJS, SCSS). Three apps, shared libraries, per-customer configuration, theming, and the local and fiscal rules of every country we run in.
• Make the apps talk to real hardware: barcode scanners, NFC, card readers, printers, scales and POS peripherals through Capacitor and native plugins, and ship them with Android Studio and Xcode.
• Build on our PHP backend: Slim, PHP-DI, JWT middleware, mPDF, the Google API client, and the endpoints behind authentication, payments, printing and push notifications.
• Keep authentication solid: JWT access and refresh tokens, SSO with PKCE, exchanging external tokens for our own, API keys for integrations. This is the part where getting it right matters a lot.
• Shape the data model in MySQL/MariaDB, write the SQL, and ship schema changes and migrations without anyone noticing.
• Look after the Management System (PHP and JavaScript), including the Aptic and platform-specific plugins, configuration and access controls.
• Care about quality the way we do: GitLab CI, ESLint, Jasmine/Karma, Cypress, and a Java API test suite (Maven, REST Assured, JUnit).
• Understand how it all runs: Linux VPSs behind a load balancer, dedicated database server, private networks and a high-availability ingress. You will deploy to it and debug it.
• Lead the technical design of new features and integrations. Write the specs, make the architecture decisions, document the trade-offs, and keep us honest about speed versus maintainability.
• Mentor mid-level and junior developers. Lead code reviews, set the standards, and make the team better than it was when you joined.
• Be the technical go-to for product, architecture, QA and business stakeholders, and for the payment, identity and device vendors we work with.
• When production breaks, lead the fix, find the root cause, and make sure it does not happen again.
• Drive how we use AI and specs as a team: the review rules, the quality gates, which tools and agent workflows are worth adopting, and how to coach others on using them well.

Key qualifications:

Must have:

• A degree in Computer Science or similar, or the experience that makes it irrelevant.
• 6+ years building software professionally, at least 3 of them shipping production apps with Angular and TypeScript.
• You already use AI coding assistants or agentic tools every day to build real software, and you know where they shine, where they fall over, and how to review what they produce.
• You have worked spec-first for real: writing specs and acceptance criteria, using them as the contract with product and QA, and feeding them to AI tools as well as to people.
• • Strong software engineering foundations: clean code, design patterns, domain-driven design, SOLID, layered or hexagonal architecture, and the judgement to know when each one applies. We expect you to hold the AI to these standards, not lower them.
• Strong hands-on PHP, ideally with Slim or a similar micro-framework, and solid REST API design.
• Strong relational database skills on MySQL/MariaDB: modelling, SQL, migrations, data transformations.
• Solid understanding of authentication: JWT, OAuth2/OIDC with PKCE, SSO, API keys.
• Experience integrating payment providers or terminals, including the webhook and state-handling side.
• Experience with hybrid mobile (Ionic with Capacitor or Cordova), native plugins and hardware.
• Comfortable with Git, CI/CD, automated testing and code quality tooling.
• You have led technical design and mentored developers before, and people would say you made them better.
• English proficiency, both written and spoken.

Nice have:

• Hands-on with Adyen, PineLabs, NETS or similar, or with POS, printer, scale, NFC or barcode hardware.
• Firebase Cloud Messaging or other push notification services.
• SCIM provisioning and enterprise identity providers.
• Multi-tenant or white-label apps with runtime configuration, theming, internationalisation and fiscal rules across countries.
• Java API test automation (Maven, REST Assured, JUnit).
• Linux servers, load balancers, private networking, high-availability setups.
• You have set up AI-assisted workflows for a team before (context files, prompt libraries, coding agents, automated review or test generation), or built LLM features into a product.
• You know the food service, retail or hospitality world.

Personal skills:

• You take ownership. Ambiguous problem in, working software out, and you stand behind it.
• You explain things clearly, to engineers and to people who have never opened a terminal.
• You enjoy making other people better, through reviews, pairing and honest feedback.
• You are careful where it counts. Payments, security and compliance do not forgive sloppiness.

What ISS Offers You:

We focus on creating an environment where you can grow and perform at your best:

• Permanent contract.
• Competitive compensation package based on your experience, including private health insurance.
• 22 days of annual leave + 3 additional company days to recharge.
• Flexible working hours and a hybrid model that supports balance and collaboration.
• Continuous learning opportunities (technical and behavioral development) to support your growth.
• Modern, well-equipped office in the heart of Porto.
• Free parking for your convenience.
• Access to ISS Tech Communities to connect, learn and share knowledge.
• Free access to the company gym to support your wellbeing.
• Snacks and drinks available at the office.

Why ISS

At ISS, we are more than just a service provider of cleaning, food, workplace and technical services, we are a partner in our customers’ success. By creating exceptional service moments and transforming workplaces into spaces where employees feel valued, engaged and productive, we enhance productivity and help our customers to attract talent and grow their businesses. This begins with our own people through training, career development, and a supportive culture – empowering them to deliver outstanding service. We know that when our people thrive, they create spaces where our customers’ employees and businesses thrive too.

ISS is a Place to Be You.

Be who you are. Become what you want. Be part of something bigger.

Become more. Become ISS.

ISS seeks to BE a place of belonging and CREATE places where every person is welcomed, embraced, and valued for exactly who they are. Places where people feel safe, respected, represented, and supported as their authentic selves.

#LI-Hybrid