Company Description

We Elevate. Digitally.

SQLI is a European player and market leader in customer experience and digital transformation, helping major international brands create value through technology and digital innovation. From strategy to the effective implementationof technological solutions, we design and build robust, high-performance architectures and engaging digital experiences, combining advanced technologies, proven methodologies, and deep expertise.

To strengthen our teams (2,200 employees across 12 countries), we are looking for driven talent who share our values: Creativity, Engagement, and a Future-minded approach.

From our Diegem office, you will operate at the heart of the business, partnering with experienced sales colleagues and key stakeholders across delivery, finance, and operations to shape and close high-impact opportunities.

We’re looking for a Shopify Back-end Developer who takes ownership of the technical backbone of our e-commerce projects.

You don’t just write code, you build robust, scalable solutions that make a real impact. From custom integrations and app development to optimizing performance and architecture, you ensure every Shopify build is ready to perform, scale, and evolve.

Job Description

We are looking for a Senior Shopify Backend Developer to support the delivery of mid to large-scale ecommerce projects, often in headless architectures and involving multiple integrations (ERP, PIM, middleware).

You will play a key role in designing and implementing backend services and Shopify apps, working closely with architects, Product Owners, Business Analysts and frontend teams.

Job Description

• You handle complex problems without overcomplicating things.

You break them down and keep moving forward.

• You take ownership of what you build.

From idea to release, you make sure features actually work in practice.

• You work well within existing systems.

Architecture, integrations and middleware don’t slow you down, you know how to improve them.

• You keep things practical.

No unnecessary complexity, just solid solutions that get the job done.

Shopify Backend Development

• Develop and maintain custom apps on Shopify

• Work extensively with:

  • Admin API (GraphQL)

  • Webhooks (event-driven flows)

  • Metafields & custom data structures

• Implement backend logic using Shopify Functions and Checkout extensibility

Integration & Data Flows

• Design and implement integrations with:

  • ERP systems (SAP, Odoo, MS Dynamics, …)

  • PIM systems

  • POS (kassa systems)

Backend Engineering

• Build scalable backend services using:

  • TypeScript / JavaScript

  • Node.js

  • Work with frameworks such as NestJS or similar structured backend frameworks

Qualifications

Must-have

• 5+ years in backend development

• Proven experience with Shopify APIs & app development

• Experience in:

  • Remix, Polaris, Liquid, Storefront API, Admin API, GraphQL, Shopify APP extensions, Shopify APP, Typescript, Shopify Flow basics, Shopify configuration

• Experience with event-driven architectures (webhooks, async processing)

Nice-to-have

• Experience with NestJS, React Router 7, PHP, Tailwind CSS basics, Hydrogren theming

• Experience in headless commerce architectures

• Exposure to B2B ecommerce (pricing, catalogs, workflows)

• Strong problem solver in complex environments

• Able to design and deliver features end-to-end

• Comfortable working with existing architecture & middleware

• Pragmatic mindset (not over-engineering)

Additional Information

• Highly competitive salary package

• Hospitalization insurance

• Company car with charging card

• Meal allowance & monthly allowance

• Phone subscription and laptop

• Flexible cafeteria plan

• 13th month salary and holiday allowance

• Access to multiple offices across Belgium

• Hybrid working model with 2 to 3 days remote, depending on client meetings and pitches

• International collaboration across 12 countries, working with diverse teams and markets

• A high-performance environment where initiative and ownership are expected and recognized

• Direct exposure to senior stakeholders and decision-makers, both internally and on the client side “