Key Responsibilities The Full Stack Engineer builds and runs the digital surfaces the Commercial STO puts in front of Expereo's Customers as well as Commercial and Service Pperations teams, front to back: the React front ends, the service layer those front ends consume, and the integrations that connect them to Salesforce and the wider systems landscape. You will join the Commercial STO, the technology team that owns the systems behind how Expereo quotes, orders, and activates services. A central part of that work is expereoOneNext, the platform that moves request intake, site creation, quoting, order placement, and service activation out of inboxes and spreadsheets and into one place. It is live with its first users and growing, and you will carry features on it from the first conversation with the people who use it to the release that reaches them. This is a hands-on engineering role with a front-end center of gravity and full-stack reach. You are strongest in React and TypeScript, fluent in the Node.js layer between the browser and the backend, and able to deliver a feature end-to-end, including the service and integration parts. You will read and work in C#/.NET at the integration points with the systems around the platform. You own what you ship, in production, and you are the engineer others on the team rely on to get it right.

Front-end delivery

Own the React and TypeScript front ends of the surfaces you work on, from component structure and state management to data fetching, caching, and performance

Turn requirements from commercial and operations users into production-quality experiences that make their daily work faster and less error-prone

Keep the front-end codebase coherent as it grows: shared components, consistent patterns, and a design language that holds across screens

Bring the consumer's view into API design: what the interface needs to look like for the front end to be simple, fast, and correct

End-to-end feature delivery

Implement the service layer each feature needs, REST or GraphQL, working contract-first from OpenAPI specifications

Build and maintain the integrations with Salesforce and other core systems that commercial data flows through, so that what a user enters on the platform arrives correctly where it is needed downstream

Implement authentication and authorization for the features you build, so access is secure by default rather than by exception

Keep the interfaces you introduce versioned and backward-compatible; downstream consumers are never broken silently

Read and work at the C#/.NET integration points with the wider systems landscape when a feature crosses them





Delivery and operations

Own the delivery path for what you ship: configure, deploy, observe, and operate your own surfaces on a managed cloud (AWS), working with the team's DevOps engineers on the shared pipeline rather than waiting on it

Use feature flags as the delivery mechanism: ship behind a default-off flag, prove with real use, remove the flag last

Write tests that give real confidence, not coverage numbers, and drive automated quality gates in CI

Diagnose and resolve production issues on the surfaces you own, so the order and activation flows commercial teams depend on keep working

Maintain living technical documentation: API specs, architecture decision records, and integration guides that let another engineer pick the work up

Collaboration

Work directly with product owners, quote management, service operations, the architect in the Innovation team, and the other engineering teams whose systems the platform connects to

Translate technical constraints and design decisions into plain language for commercial and operations stakeholders

Participate in design reviews, sprint reviews, and technical decision-making; propose approaches and flag risks early

Raise the bar through code review, example implementations, and clear written reasoning about trade-offs, and help onboard other engineers onto the codebase

Requirements Must have

Five plus years of professional software engineering, with production React and TypeScript front ends as your core stack

Node.js and TypeScript services in production, and comfort implementing the layer between the front end and the backend for the features you own

REST and/or GraphQL APIs implemented and consumed in production, with contract-first OpenAPI as a working method

Ownership of the delivery path for what you ship: you configure, deploy, observe, and operate your own work on a managed cloud, with CI/CD as part of how you work rather than someone else's job

Software engineering discipline: testing, code review, Git, feature flags, and reproducible builds. You build things other people can maintain

Ability to work in a mixed-language environment. The systems around the platform include C#/.NET. You do not need to be expert in it, but you need to read it,



understand the integration points, and be willing to write in it

Strong nice to have

Integration experience with Salesforce, including data models, APIs, and keeping two systems consistent

AWS services in practice: Amplify, Lambda, API Gateway, Cognito, S3, or equivalent

OAuth2 and OIDC in practice (Cognito, Okta, or equivalent), including scope models and token lifecycle

C#/.NET backend exposure, enough to contribute at the integration points

Event-driven or asynchronous integration: queues, SQS, EventBridge, Kafka, or similar

Front-end architecture beyond a single application: micro front ends, module federation, or comparable patterns

Also Welcome, Not Required

Experience with DDD, CQS, or event-driven architectural patterns

Comfort producing C4 diagrams, ADRs, and integration guides

Experience building internal tools for sales, quoting, or order management teams

Connectivity, SD-WAN, SASE, or network platform domain background. Not required; useful if you have it

Collaboration and mindset

Product-minded: you think about the person on the other side of the screen, not just the endpoint behind it

End-to-end ownership: you would rather carry a feature from the first component to the last deployment than hand it off halfway

Reliability matters to you: the people using what you build depend on it to do their jobs

Prefer building the right thing simply over building the perfect thing slowly

Contract-first is a value, not just a technique

Curious across the stack: the boundaries of your role are set by what the feature needs, not by the language you started in

Benefits

Part of a team that is engaged and owning the things they do, highly trustable with direct commercial stakes

Direct access to production systems, real data, and decision-makers — no layers of process between your work and its impact

Exposure to cutting-edge technologies and large-scale general networks

A role designed with trajectory in mind — the knowledge you build here is directly applicable to a senior technical execution path

Competitive compensation and local benefits

Hybrid Working

Beyond the Job We're proud of our focus on as Environment, Social and Governance as well as the passion we display for the communities where we live and work.

EEO Statement Expereo is an Equal Opportunities employer who aims to support and celebrate every employee that comes through our doors. We respect and support all of our people regardless of background, religion, nationality, sexual orientation, age, or physical condition.

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📌 Senior Full-Stack Engineer (Barcelona)
🏢 Expereo International
📍 Barcelona